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<strong>Chemistry</strong> Honors <strong>Notebook</strong><br />

2017-2018<br />

By: Emisael Vega Avila


Reference Tables for Physical Setting/CHEMISTRY<br />

Table A<br />

Standard Temperature and Pressure<br />

Name Value Unit<br />

Standard Pressure 101.3 kPa kilopascal<br />

1 atm atmosphere<br />

Standard Temperature 273 K kelvin<br />

0°C degree Celsius<br />

Table D<br />

Selected Units<br />

Symbol Name Quantity<br />

m meter length<br />

g gram mass<br />

Pa pascal pressure<br />

K kelvin temperature<br />

Table B<br />

Physical Constants for Water<br />

mol<br />

J<br />

mole<br />

joule<br />

amount of<br />

substance<br />

energy, work,<br />

quantity of heat<br />

Heat of Fusion<br />

Heat of Vaporization<br />

Specific Heat Capacity of H 2<br />

O()<br />

Specific Heat Capacity of H 2<br />

O(s)<br />

Specific Heat Capacity of H 2<br />

O(g)<br />

Table C<br />

Selected Prefixes<br />

Factor Prefix Symbol<br />

10 3 kilo- k<br />

334 J/g<br />

2260 J/g<br />

4.18 J/g•K<br />

2.10 J/g•K<br />

2.01 J/g•K<br />

s second time<br />

min minute time<br />

h hour time<br />

d day time<br />

y year time<br />

L liter volume<br />

ppm parts per million concentration<br />

M<br />

molarity<br />

solution<br />

concentration<br />

u atomic mass unit atomic mass<br />

10 –1 deci- d<br />

10 –2 centi- c<br />

10 –3 milli- m<br />

10 –6 micro- μ<br />

10 –9 nano- n<br />

10 –12 pico- p<br />

R1


Table E<br />

Selected Polyatomic Ions<br />

Formula Name Formula Name<br />

H 3<br />

O +<br />

hydronium<br />

CrO 4<br />

2–<br />

chromate<br />

Hg 2<br />

2+<br />

mercury(I)<br />

Cr 2<br />

O 7<br />

2–<br />

dichromate<br />

NH 4<br />

+<br />

C 2<br />

H 3<br />

O<br />

–<br />

2 –}<br />

CH 3<br />

COO<br />

CN –<br />

CO 3<br />

2–<br />

HCO<br />

–<br />

3<br />

C 2<br />

O<br />

2–<br />

4<br />

ClO –<br />

ammonium<br />

acetate<br />

cyanide<br />

carbonate<br />

hydrogen<br />

carbonate<br />

oxalate<br />

hypochlorite<br />

MnO 4<br />

–<br />

NO<br />

–<br />

2<br />

NO<br />

–<br />

3<br />

O<br />

2–<br />

2<br />

OH –<br />

PO 4<br />

3–<br />

SCN –<br />

SO 3<br />

2–<br />

permanganate<br />

nitrite<br />

nitrate<br />

peroxide<br />

hydroxide<br />

phosphate<br />

thiocyanate<br />

sulfite<br />

ClO 2<br />

–<br />

chlorite<br />

SO 4<br />

2–<br />

sulfate<br />

ClO 3<br />

–<br />

chlorate<br />

HSO 4<br />

–<br />

hydrogen sulfate<br />

ClO 4<br />

–<br />

perchlorate<br />

S 2<br />

O 3<br />

2–<br />

thiosulfate<br />

Table F<br />

Solubility Guidelines for Aqueous Solutions<br />

Ions That Form<br />

Soluble Compounds<br />

Group 1 ions<br />

(Li + , Na + , etc.)<br />

ammonium (NH 4 + )<br />

nitrate (NO 3 – )<br />

acetate (C 2<br />

H 3<br />

O 2 – or<br />

CH 3<br />

COO – )<br />

hydrogen carbonate<br />

(HCO 3 – )<br />

chlorate (ClO 3 – )<br />

halides (Cl – , Br – , I – )<br />

Exceptions<br />

when combined with<br />

Ag + , Pb 2+ , or Hg 2<br />

2+<br />

sulfates (SO 4 2– ) when combined with Ag + ,<br />

Ca 2+ , Sr 2+ , Ba 2+ , or Pb 2+<br />

Ions That Form<br />

Insoluble Compounds*<br />

Exceptions<br />

carbonate (CO 3 2– ) when combined with Group 1<br />

ions or ammonium (NH 4 + )<br />

chromate (CrO 4 2– ) when combined with Group 1<br />

ions, Ca 2+ , Mg 2+ , or<br />

ammonium (NH 4 + )<br />

phosphate (PO 4 3– ) when combined with Group 1<br />

ions or ammonium (NH 4 + )<br />

sulfide (S 2– ) when combined with Group 1<br />

ions or ammonium (NH 4 + )<br />

hydroxide (OH – ) when combined with Group 1<br />

ions, Ca 2+ , Ba 2+ , Sr 2+ , or<br />

ammonium (NH 4 + )<br />

*compounds having very low solubility in H 2 O<br />

R2


150.<br />

140.<br />

Table G<br />

Solubility Curves at Standard Pressure<br />

KI<br />

NaNO 3<br />

130.<br />

120.<br />

KNO 3<br />

110.<br />

100.<br />

Solubility (g solute/100. g H 2<br />

O)<br />

90.<br />

80.<br />

70.<br />

60.<br />

HCl<br />

NH 4<br />

Cl<br />

KCl<br />

50.<br />

40.<br />

30.<br />

NaCl<br />

KClO 3<br />

NH 3<br />

20.<br />

10.<br />

SO 2<br />

0<br />

0 10. 20. 30. 40. 50. 60. 70. 80. 90. 100.<br />

Temperature (°C)<br />

R3


Table H<br />

Vapor Pressure of Four Liquids<br />

200.<br />

propanone<br />

ethanol<br />

150.<br />

water<br />

Vapor Pressure (kPa)<br />

100.<br />

101.3 kPa<br />

ethanoic<br />

acid<br />

50.<br />

0<br />

0 25 50. 75 100. 125<br />

R4


Table I<br />

Heats of Reaction at 101.3 kPa and 298 K<br />

Reaction<br />

ΔH (kJ)*<br />

CH 4<br />

(g) + 2O 2<br />

(g) CO 2<br />

(g) + 2H 2<br />

O() –890.4<br />

C 3<br />

H 8<br />

(g) + 5O 2<br />

(g) 3CO 2<br />

(g) + 4H 2<br />

O() –2219.2<br />

2C 8<br />

H 18<br />

() + 25O 2<br />

(g) 16CO 2<br />

(g) + 18H 2<br />

O() –10943<br />

2CH 3<br />

OH() + 3O 2<br />

(g) 2CO 2<br />

(g) + 4H 2<br />

O() –1452<br />

C 2<br />

H 5<br />

OH() + 3O 2<br />

(g) 2CO 2<br />

(g) + 3H 2<br />

O() –1367<br />

C 6<br />

H 12<br />

O 6<br />

(s) + 6O 2<br />

(g) 6CO 2<br />

(g) + 6H 2<br />

O() –2804<br />

2CO(g) + O 2<br />

(g) 2CO 2<br />

(g) –566.0<br />

C(s) + O 2<br />

(g) CO 2<br />

(g) –393.5<br />

4Al(s) + 3O 2<br />

(g) 2Al 2<br />

O 3<br />

(s) –3351<br />

N 2<br />

(g) + O 2<br />

(g) 2NO(g) +182.6<br />

N 2<br />

(g) + 2O 2<br />

(g) 2NO 2<br />

(g) +66.4<br />

2H 2<br />

(g) + O 2<br />

(g) 2H 2<br />

O(g) –483.6<br />

2H 2<br />

(g) + O 2<br />

(g) 2H 2<br />

O() –571.6<br />

N 2<br />

(g) + 3H 2<br />

(g) 2NH 3<br />

(g) –91.8<br />

2C(s) + 3H 2<br />

(g) C 2<br />

H 6<br />

(g) –84.0<br />

2C(s) + 2H 2<br />

(g) C 2<br />

H 4<br />

(g) +52.4<br />

2C(s) + H 2<br />

(g) C 2<br />

H 2<br />

(g) +227.4<br />

H 2<br />

(g) + I 2<br />

(g) 2HI(g) +53.0<br />

KNO 3<br />

(s) H 2 O K + (aq) + NO 3 – (aq) +34.89<br />

NaOH(s) H 2 O Na + (aq) + OH – (aq) –44.51<br />

NH 4<br />

Cl(s) H 2 O NH 4 + (aq) + Cl – (aq) +14.78<br />

NH 4<br />

NO 3<br />

(s) H 2 O NH 4 + (aq) + NO 3 – (aq) +25.69<br />

NaCl(s) H 2 O Na + (aq) + Cl – (aq) +3.88<br />

LiBr(s) H 2 O Li + (aq) + Br – (aq) –48.83<br />

H + (aq) + OH – (aq) H 2<br />

O() –55.8<br />

*The ΔH values are based on molar quantities represented in the equations.<br />

A minus sign indicates an exothermic reaction.<br />

Most<br />

Active<br />

Least<br />

Active<br />

Table J<br />

Activity Series**<br />

Metals Nonmetals Most<br />

Active<br />

Li<br />

Rb<br />

K<br />

Cs<br />

Ba<br />

Sr<br />

Ca<br />

Na<br />

Mg<br />

Al<br />

Ti<br />

Mn<br />

Zn<br />

Cr<br />

Fe<br />

Co<br />

Ni<br />

Sn<br />

Pb<br />

H 2<br />

Cu<br />

Ag<br />

Au<br />

F 2<br />

Cl 2<br />

Br 2<br />

I 2<br />

**Activity Series is based on the hydrogen<br />

standard. H 2 is not a metal.<br />

Least<br />

Active<br />

R5


Table K<br />

Common Acids<br />

Table N<br />

Selected Radioisotopes<br />

HCl(aq)<br />

Formula<br />

HNO 2<br />

(aq)<br />

HNO 3<br />

(aq)<br />

H 2<br />

SO 3<br />

(aq)<br />

H 2<br />

SO 4<br />

(aq)<br />

H 3<br />

PO 4<br />

(aq)<br />

H 2<br />

CO 3<br />

(aq)<br />

or<br />

CO 2<br />

(aq)<br />

CH 3<br />

COOH(aq)<br />

or<br />

HC 2<br />

H 3<br />

O 2<br />

(aq)<br />

Name<br />

hydrochloric acid<br />

nitrous acid<br />

nitric acid<br />

sulfurous acid<br />

sulfuric acid<br />

phosphoric acid<br />

carbonic acid<br />

ethanoic acid<br />

(acetic acid)<br />

Nuclide Half-Life Decay<br />

Mode<br />

Nuclide<br />

Name<br />

198 Au 2.695 d β – gold-198<br />

14 C 5715 y β – carbon-14<br />

37 Ca 182 ms β + calcium-37<br />

60 Co 5.271 y β – cobalt-60<br />

137 Cs 30.2 y β – cesium-137<br />

53 Fe 8.51 min β + iron-53<br />

220 Fr 27.4 s α francium-220<br />

3 H 12.31 y β – hydrogen-3<br />

131 I 8.021 d β – iodine-131<br />

37 K 1.23 s β + potassium-37<br />

42 K 12.36 h β – potassium-42<br />

Table L<br />

Common Bases<br />

85 Kr 10.73 y β – krypton-85<br />

16 N 7.13 s β – nitrogen-16<br />

Formula<br />

NaOH(aq)<br />

KOH(aq)<br />

Ca(OH) 2<br />

(aq)<br />

NH 3<br />

(aq)<br />

Name<br />

sodium hydroxide<br />

potassium hydroxide<br />

calcium hydroxide<br />

aqueous ammonia<br />

19 Ne 17.22 s β + neon-19<br />

32 P 14.28 d β – phosphorus-32<br />

239 Pu 2.410 × 10 4 y α plutonium-239<br />

226 Ra 1599 y α radium-226<br />

222 Rn 3.823 d α radon-222<br />

90 Sr 29.1 y β – strontium-90<br />

Table M<br />

Common Acid–Base Indicators<br />

Approximate<br />

Indicator pH Range Color<br />

for Color Change<br />

Change<br />

methyl orange 3.1–4.4 red to yellow<br />

bromthymol blue 6.0–7.6 yellow to blue<br />

phenolphthalein 8–9 colorless to pink<br />

litmus 4.5–8.3 red to blue<br />

bromcresol green 3.8–5.4 yellow to blue<br />

thymol blue 8.0–9.6 yellow to blue<br />

99 Tc 2.13 × 10 5 y β – technetium-99<br />

232 Th 1.40 × 10 10 y α thorium-232<br />

233 U 1.592 × 10 5 y α uranium-233<br />

235 U 7.04 × 10 8 y α uranium-235<br />

238 U 4.47 × 10 9 y α uranium-238<br />

Source: CRC Handbook of <strong>Chemistry</strong> and Physics, 91 st ed., 2010–2011,<br />

CRC Press<br />

Source: The Merck Index, 14 th ed., 2006, Merck Publishing Group<br />

R6


Table O<br />

Symbols Used in Nuclear <strong>Chemistry</strong><br />

Name Notation Symbol<br />

alpha particle<br />

4<br />

2<br />

He or 4 2 α α<br />

beta particle<br />

0<br />

–1<br />

e or 0<br />

–1 β β–<br />

gamma radiation<br />

0<br />

0<br />

γ γ<br />

neutron<br />

1<br />

0<br />

n n<br />

proton<br />

1<br />

1<br />

H or 1 1 p p<br />

positron<br />

0<br />

+1<br />

e or 0<br />

+1 β β+<br />

Table P<br />

Organic Prefixes<br />

Prefix<br />

meth- 1<br />

eth- 2<br />

prop- 3<br />

but- 4<br />

pent- 5<br />

hex- 6<br />

hept- 7<br />

oct- 8<br />

non- 9<br />

dec- 10<br />

Number of<br />

Carbon Atoms<br />

Table Q<br />

Homologous Series of Hydrocarbons<br />

Name General Examples<br />

Formula Name Structural Formula<br />

R7<br />

alkanes C n<br />

H 2n+2<br />

ethane<br />

alkenes C n<br />

H 2n<br />

ethene<br />

alkynes C n<br />

H 2n–2<br />

ethyne<br />

Note: n = number of carbon atoms<br />

H H<br />

H C C H<br />

H H<br />

H<br />

H<br />

C C<br />

H<br />

H<br />

H C C H


Table R<br />

Organic Functional Groups<br />

Class of<br />

Compound<br />

Functional<br />

Group<br />

General<br />

Formula<br />

Example<br />

halide<br />

(halocarbon)<br />

F (fluoro-)<br />

Cl (chloro-)<br />

Br (bromo-)<br />

I (iodo-)<br />

R X<br />

(X represents<br />

any halogen)<br />

CH 3<br />

CHClCH 3<br />

2-chloropropane<br />

alcohol<br />

OH<br />

R<br />

OH<br />

CH 3<br />

CH 2<br />

CH 2<br />

OH<br />

1-propanol<br />

ether<br />

O<br />

R O R′<br />

CH 3<br />

OCH 2<br />

CH 3<br />

methyl ethyl ether<br />

aldehyde<br />

O<br />

C H<br />

R<br />

O<br />

C H<br />

O<br />

CH 3<br />

CH 2<br />

C H<br />

propanal<br />

ketone<br />

O<br />

C<br />

O<br />

R C R′<br />

O<br />

CH 3<br />

CCH 2<br />

CH 2<br />

CH 3<br />

2-pentanone<br />

organic acid<br />

O<br />

C OH<br />

R<br />

O<br />

C OH<br />

O<br />

CH 3<br />

CH 2<br />

C OH<br />

propanoic acid<br />

ester<br />

O<br />

C O<br />

O<br />

R C O R′<br />

O<br />

CH 3<br />

CH 2<br />

COCH 3<br />

methyl propanoate<br />

amine<br />

N<br />

R<br />

R′<br />

N R′′<br />

CH 3<br />

CH 2<br />

CH 2<br />

NH 2<br />

1-propanamine<br />

amide<br />

O<br />

C NH<br />

R<br />

O R′<br />

C NH<br />

O<br />

CH 3<br />

CH 2<br />

C NH 2<br />

propanamide<br />

Note: R represents a bonded atom or group of atoms.<br />

R8


0<br />

6.941<br />

+1<br />

Li<br />

3<br />

2-1<br />

Na<br />

39.0983<br />

K +1<br />

19<br />

2-8-8-1<br />

85.4678 +1<br />

Rb<br />

Cs<br />

(223)<br />

Fr<br />

87<br />

-18-32-18-8-1<br />

+1<br />

Ra<br />

88<br />

-18-32-18-8-2<br />

39<br />

138.9055<br />

La<br />

57<br />

2-8-18-18-9-2<br />

+2 (227)<br />

Ac<br />

89<br />

-18-32-18-9-2<br />

47.867<br />

Ti<br />

22<br />

2-8-10-2<br />

91.224<br />

Zr<br />

40<br />

2-8-18-10-2<br />

+3 178.49<br />

Hf<br />

72<br />

*18-32-10-2<br />

+3 (261)<br />

Rf<br />

104<br />

+2<br />

+3<br />

+4<br />

+4<br />

+4<br />

50.9415<br />

V<br />

23<br />

2-8-11-2<br />

+2<br />

+3<br />

+4<br />

+5<br />

51.996<br />

Cr<br />

24<br />

2-8-13-1<br />

95.94<br />

Mo<br />

42<br />

2-8-18-13-1<br />

183.84<br />

W<br />

74<br />

-18-32-12-2<br />

+2<br />

+3<br />

+6<br />

+6<br />

+6<br />

54.9380<br />

Mn<br />

25<br />

2-8-13-2<br />

+2<br />

+3<br />

+4<br />

+7<br />

55.845<br />

Fe<br />

26<br />

2-8-14-2<br />

+2<br />

+3 58.9332<br />

Co<br />

27<br />

2-8-15-2<br />

+2<br />

+3<br />

58.693<br />

Ni<br />

28<br />

2-8-16-2<br />

+2<br />

+3 63.546 Cu<br />

2-8-18-1<br />

107.868<br />

Ag<br />

47<br />

2-8-18-18-1<br />

79<br />

+1<br />

+2<br />

+1<br />

65.409<br />

Zn<br />

30<br />

2-8-18-2<br />

10.81<br />

+3 12.011<br />

B<br />

5<br />

2-3<br />

26.98154<br />

Al<br />

13<br />

2-8-3<br />

+2 69.723<br />

Ga<br />

31<br />

2-8-18-3<br />

+3<br />

+3<br />

–4<br />

+2<br />

+4<br />

C<br />

6<br />

2-4<br />

28.0855<br />

Si<br />

14<br />

2-8-4<br />

72.64<br />

Ge<br />

32<br />

2-8-18-4<br />

Pb<br />

–4<br />

+2<br />

+4<br />

+2<br />

+4<br />

74.9216<br />

As<br />

33<br />

2-8-18-5<br />

Sb<br />

–3<br />

+3<br />

15.9994 O<br />

–2 18.9984<br />

8<br />

2-6 2-7<br />

78.96<br />

Se<br />

34<br />

2-8-18-6<br />

127.60<br />

Te<br />

52<br />

2-8-18-18-6<br />

(209)<br />

Po<br />

84<br />

-18-32-18-6<br />

–2<br />

+4<br />

+6<br />

–2<br />

+4<br />

+6<br />

+2<br />

+4<br />

F<br />

79.904<br />

Br<br />

35<br />

2-8-18-7<br />

126.904<br />

l<br />

53<br />

2-8-18-18-7<br />

(210)<br />

At<br />

85<br />

-18-32-18-7<br />

( ? )<br />

Uus<br />

117<br />

4.00260 0<br />

He<br />

2<br />

2<br />

–1 20.180<br />

Ne<br />

10<br />

2-8<br />

0<br />

22.98977<br />

11<br />

2-8-1<br />

1<br />

1.00794 +1<br />

–1<br />

H<br />

1<br />

1<br />

1<br />

37<br />

2-8-18-8-1<br />

–1<br />

+1<br />

+5<br />

–1<br />

+1<br />

+5<br />

+7<br />

83.798<br />

Kr<br />

36<br />

2-8-18-8<br />

131.29<br />

Xe<br />

54<br />

2-8-18-18-8<br />

(222)<br />

Rn<br />

86<br />

-18-32-18-8<br />

0<br />

+2<br />

0<br />

+2<br />

+4<br />

+6<br />

0<br />

132.905<br />

55<br />

2-8-18-18-8-1<br />

Symbol<br />

Relative atomic masses are based<br />

Group on 12 C = 12 (exact)<br />

Group<br />

2<br />

13 14 15 16 17 18<br />

Atomic Number<br />

+1<br />

+1<br />

9.01218 +2<br />

Be<br />

4<br />

2-2<br />

24.305<br />

Mg<br />

12<br />

2-8-2<br />

40.08<br />

Ca<br />

20<br />

2-8-8-2<br />

87.62<br />

Sr<br />

38<br />

2-8-18-8-2<br />

137.33<br />

Ba<br />

56<br />

2-8-18-18-8-2<br />

(226)<br />

+2<br />

+2<br />

+2<br />

+2<br />

3<br />

44.9559<br />

Sc<br />

21<br />

2-8-9-2<br />

88.9059<br />

Y<br />

2-8-18-9-2<br />

+3<br />

+3<br />

4<br />

KEY<br />

92.9064<br />

Nb +3<br />

+5<br />

41<br />

2-8-18-12-1<br />

180.948<br />

Ta<br />

73<br />

-18-32-11-2<br />

(262)<br />

105<br />

5<br />

Periodic Table of the Elements<br />

Atomic Mass<br />

Electron Configuration<br />

+4<br />

Db<br />

+5<br />

6<br />

(266)<br />

Sg<br />

106<br />

12.011 2-4<br />

–4<br />

6<br />

C<br />

+2<br />

+4<br />

(98)<br />

Tc<br />

43<br />

2-8-18-13-2<br />

186.207<br />

Re<br />

75<br />

-18-32-13-2<br />

(272)<br />

Bh<br />

107<br />

7<br />

Group<br />

+4<br />

+6<br />

+7<br />

+4<br />

+6<br />

+7<br />

8<br />

101.07<br />

Ru<br />

44<br />

2-8-18-15-1<br />

190.23<br />

Os<br />

76<br />

-18-32-14-2<br />

(277)<br />

Hs<br />

108<br />

+3<br />

+3<br />

+4<br />

Selected Oxidation States<br />

Note: Numbers in parentheses<br />

are mass numbers of the most<br />

stable or common isotope.<br />

9<br />

102.906<br />

Rh<br />

45<br />

2-8-18-16-1<br />

192.217<br />

Ir<br />

77<br />

-18-32-15-2<br />

(276)<br />

Mt<br />

109<br />

+3<br />

+3<br />

+4<br />

106.42<br />

Pd<br />

46<br />

2-8-18-18<br />

195.08<br />

Pt<br />

78<br />

-18-32-17-1<br />

+2<br />

+4<br />

+2<br />

+4<br />

196.967<br />

Au<br />

-18-32-18-1<br />

(281)<br />

Ds (280) Rg<br />

110<br />

10<br />

29<br />

111<br />

11 12<br />

+1<br />

+3<br />

112.41<br />

Cd<br />

48<br />

2-8-18-18-2<br />

200.59<br />

Hg<br />

80<br />

-18-32-18-2<br />

(285)<br />

Cn<br />

112<br />

+2 114.818<br />

In<br />

+1<br />

+2<br />

49<br />

2-8-18-18-3<br />

204.383<br />

Tl<br />

81<br />

-18-32-18-3<br />

(284)<br />

Uut<br />

113**<br />

+3<br />

+1<br />

+3<br />

118.71<br />

Sn<br />

50<br />

2-8-18-18-4<br />

207.2<br />

82<br />

-18-32-18-4<br />

(289)<br />

Uuq<br />

114<br />

+2<br />

+4<br />

+2<br />

+4<br />

14.0067 –3<br />

–2<br />

N<br />

–1<br />

7<br />

2-5<br />

30.97376<br />

P<br />

15<br />

2-8-5<br />

121.760<br />

51<br />

2-8-18-18-5<br />

208.980<br />

Bi<br />

83<br />

-18-32-18-5<br />

(288)<br />

Uup<br />

115<br />

+1<br />

+2<br />

+3<br />

+4<br />

+5<br />

–3<br />

+3<br />

+5<br />

+5<br />

–3<br />

+3<br />

+5<br />

+3<br />

+5<br />

32.065<br />

S<br />

16<br />

2-8-6<br />

(292)<br />

Uuh<br />

116<br />

–2<br />

+4<br />

+6<br />

35.453<br />

Cl<br />

17<br />

2-8-7<br />

–1<br />

+1<br />

+5<br />

+7<br />

39.948<br />

Ar<br />

18<br />

2-8-8<br />

18<br />

(294)<br />

Uuo<br />

118<br />

140.116<br />

Ce<br />

58<br />

232.038<br />

Th<br />

90<br />

+3<br />

+4<br />

140.908<br />

Pr +3<br />

59<br />

144.24<br />

Nd<br />

60<br />

+4 231.036<br />

Pa +4 238.029 +5<br />

U +3<br />

+4<br />

+5<br />

+6<br />

91<br />

92<br />

+3<br />

(145)<br />

Pm<br />

61<br />

+3<br />

150.36<br />

Sm<br />

62<br />

+2<br />

+3<br />

151.964<br />

Eu<br />

63<br />

+2<br />

+3<br />

157.25<br />

Gd<br />

64<br />

+3<br />

158.925<br />

(237)Np (244) Pu (243) Am (247) Cm +3 (247) Bk +3<br />

+3<br />

+4<br />

+5<br />

+6<br />

93 94<br />

+3<br />

+4<br />

+5<br />

+6<br />

65<br />

+3<br />

+4<br />

+5<br />

+6<br />

95 96 97<br />

Tb<br />

+3<br />

+4<br />

162.500<br />

Dy<br />

66<br />

(251)<br />

+3<br />

164.930<br />

Ho<br />

67<br />

+3<br />

167.259<br />

Er<br />

68<br />

Cf +3 (252) Es (257) Fm<br />

100<br />

98 99<br />

+3<br />

+3<br />

+3<br />

168.934<br />

Tm +3<br />

69<br />

(258)<br />

Md<br />

101<br />

+2<br />

+3<br />

173.04<br />

Yb<br />

70<br />

(259)<br />

No<br />

102<br />

+2<br />

+3<br />

+2<br />

+3<br />

174.9668<br />

Lu<br />

71<br />

(262)<br />

Lr<br />

103<br />

+3<br />

+3<br />

*denotes the presence of (2-8-) for elements 72 and above<br />

**The systematic names and symbols for elements of atomic numbers 113 and above<br />

will be used until the approval of trivial names by IUPAC.<br />

Source: CRC Handbook of <strong>Chemistry</strong> and Physics, 91 st ed., 2010–2011, CRC Press<br />

9<br />

R9<br />

Period<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

7


Table S<br />

Properties of Selected Elements<br />

First<br />

Atomic Symbol Name Ionization<br />

Electro- Melting Boiling* Density** Atomic<br />

Number Energy negativity Point Point (g/cm 3 ) Radius<br />

(kJ/mol) (K) (K) (pm)<br />

1 H hydrogen 1312 2.2 14 20. 0.000082 32<br />

2 He helium 2372 — — 4 0.000164 37<br />

3 Li lithium 520. 1.0 454 1615 0.534 130.<br />

4 Be beryllium 900. 1.6 1560. 2744 1.85 99<br />

5 B boron 801 2.0 2348 4273 2.34 84<br />

6 C carbon 1086 2.6 — — .— 75<br />

7 N nitrogen 1402 3.0 63 77 0.001145 71<br />

8 O oxygen 1314 3.4 54 90. 0.001308 64<br />

9 F fluorine 1681 4.0 53 85 0.001553 60.<br />

10 Ne neon 2081 — 24 27 0.000825 62<br />

11 Na sodium 496 0.9 371 1156 0.97 160.<br />

12 Mg magnesium 738 1.3 923 1363 1.74 140.<br />

13 Al aluminum 578 1.6 933 2792 2.70 124<br />

14 Si silicon 787 1.9 1687 3538 2.3296 114<br />

15 P phosphorus (white) 1012 2.2 317 554 1.823 109<br />

16 S sulfur (monoclinic) 1000. 2.6 388 718 2.00 104<br />

17 Cl chlorine 1251 3.2 172 239 0.002898 100.<br />

18 Ar argon 1521 — 84 87 0.001633 101<br />

19 K potassium 419 0.8 337 1032 0.89 200.<br />

20 Ca calcium 590. 1.0 1115 1757 1.54 174<br />

21 Sc scandium 633 1.4 1814 3109 2.99 159<br />

22 Ti titanium 659 1.5 1941 3560. 4.506 148<br />

23 V vanadium 651 1.6 2183 3680. 6.0 144<br />

24 Cr chromium 653 1.7 2180. 2944 7.15 130.<br />

25 Mn manganese 717 1.6 1519 2334 7.3 129<br />

26 Fe iron 762 1.8 1811 3134 7.87 124<br />

27 Co cobalt 760. 1.9 1768 3200. 8.86 118<br />

28 Ni nickel 737 1.9 1728 3186 8.90 117<br />

29 Cu copper 745 1.9 1358 2835 8.96 122<br />

30 Zn zinc 906 1.7 693 1180. 7.134 120.<br />

31 Ga gallium 579 1.8 303 2477 5.91 123<br />

32 Ge germanium 762 2.0 1211 3106 5.3234 120.<br />

33 As arsenic (gray) 944 2.2 1090. — 5.75 120.<br />

34 Se selenium (gray) 941 2.6 494 958 4.809 118<br />

35 Br bromine 1140. 3.0 266 332 3.1028 117<br />

36 Kr krypton 1351 — 116 120. 0.003425 116<br />

37 Rb rubidium 403 0.8 312 961 1.53 215<br />

38 Sr strontium 549 1.0 1050. 1655 2.64 190.<br />

39 Y yttrium 600. 1.2 1795 3618 4.47 176<br />

40 Zr zirconium 640. 1.3 2128 4682 6.52 164<br />

R10


First<br />

Atomic Symbol Name Ionization<br />

Electro- Melting Boiling* Density** Atomic<br />

Number Energy negativity Point Point (g/cm 3 ) Radius<br />

(kJ/mol) (K) (K) (pm)<br />

41 Nb niobium 652 1.6 2750. 5017 8.57 156<br />

42 Mo molybdenum 684 2.2 2896 4912 10.2 146<br />

43 Tc technetium 702 2.1 2430. 4538 11 138<br />

44 Ru ruthenium 710. 2.2 2606 4423 12.1 136<br />

45 Rh rhodium 720. 2.3 2237 3968 12.4 134<br />

46 Pd palladium 804 2.2 1828 3236 12.0 130.<br />

47 Ag silver 731 1.9 1235 2435 10.5 136<br />

48 Cd cadmium 868 1.7 594 1040. 8.69 140.<br />

49 In indium 558 1.8 430. 2345 7.31 142<br />

50 Sn tin (white) 709 2.0 505 2875 7.287 140.<br />

51 Sb antimony (gray) 831 2.1 904 1860. 6.68 140.<br />

52 Te tellurium 869 2.1 723 1261 6.232 137<br />

53 I iodine 1008 2.7 387 457 4.933 136<br />

54 Xe xenon 1170. 2.6 161 165 0.005366 136<br />

55 Cs cesium 376 0.8 302 944 1.873 238<br />

56 Ba barium 503 0.9 1000. 2170. 3.62 206<br />

57 La lanthanum 538 1.1 1193 3737 6.15 194<br />

Elements 58–71 have been omitted.<br />

72 Hf hafnium 659 1.3 2506 4876 13.3 164<br />

73 Ta tantalum 728 1.5 3290. 5731 16.4 158<br />

74 W tungsten 759 1.7 3695 5828 19.3 150.<br />

75 Re rhenium 756 1.9 3458 5869 20.8 141<br />

76 Os osmium 814 2.2 3306 5285 22.587 136<br />

77 Ir iridium 865 2.2 2719 4701 22.562 132<br />

78 Pt platinum 864 2.2 2041 4098 21.5 130.<br />

79 Au gold 890. 2.4 1337 3129 19.3 130.<br />

80 Hg mercury 1007 1.9 234 630. 13.5336 132<br />

81 Tl thallium 589 1.8 577 1746 11.8 144<br />

82 Pb lead 716 1.8 600. 2022 11.3 145<br />

83 Bi bismuth 703 1.9 544 1837 9.79 150.<br />

84 Po polonium 812 2.0 527 1235 9.20 142<br />

85 At astatine — 2.2 575 — — 148<br />

86 Rn radon 1037 — 202 211 0.009074 146<br />

87 Fr francium 393 0.7 300. — — 242<br />

88 Ra radium 509 0.9 969 — 5 211<br />

89 Ac actinium 499 1.1 1323 3471 10. 201<br />

Elements 90 and above have been omitted.<br />

*boiling point at standard pressure<br />

**density of solids and liquids at room temperature and density of gases at 298 K and 101.3 kPa<br />

— no data available<br />

Source: CRC Handbook for <strong>Chemistry</strong> and Physics, 91 st ed., 2010–2011, CRC Press<br />

R11


Table T<br />

Important Formulas and Equations<br />

d = density<br />

m<br />

Density d = m = mass<br />

V<br />

V = volume<br />

Mole Calculations number of moles =<br />

given mass<br />

gram-formula mass<br />

measured value – accepted value<br />

Percent Error % error = × 100<br />

accepted value<br />

mass of part<br />

Percent Composition % composition by mass = × 100<br />

mass of whole<br />

mass of solute<br />

parts per million = × 1000000<br />

mass of solution<br />

Concentration<br />

molarity =<br />

moles of solute<br />

liter of solution<br />

Combined Gas Law<br />

P<br />

P = pressure<br />

1<br />

V 1<br />

P<br />

= 2<br />

V 2<br />

V = volume<br />

T 1<br />

T 2 T = temperature<br />

M A<br />

= molarity of H + M B<br />

= molarity of OH –<br />

Titration M A<br />

V A<br />

= M B<br />

V B<br />

V A<br />

= volume of acid V B<br />

= volume of base<br />

q = mCΔT q = heat H f<br />

= heat of fusion<br />

Heat q = mH f<br />

m = mass H v<br />

= heat of vaporization<br />

q = mH v<br />

C=specific heat capacity<br />

ΔT = change in temperature<br />

Temperature<br />

K = °C + 273<br />

K = kelvin<br />

°C = degree Celsius<br />

R12


Collier County CHEMISTRY EXAM FORMULA AND RESOURCE PACKET<br />

GENERAL<br />

D m V<br />

[ ExperimentalValue AcceptedVa lue]<br />

% error <br />

x100<br />

AcceptedVa lue<br />

% yield <br />

ExperimentalYield<br />

TheoreticalYield<br />

x100<br />

CONCENTRATIONS<br />

moles of solute<br />

M = Molarity <br />

liters of solution<br />

KEY<br />

P = pressure<br />

V = volume<br />

T = temperature<br />

n = number of moles<br />

m = mass<br />

M = molar mass (grams/mole)<br />

D = density<br />

KE = kinetic energy<br />

Avogadro’s Number = 6.02 x 10 23<br />

GASES, LIQUIDS, SOLUTIONS<br />

m = Molality <br />

M1V1 M2V2<br />

S1<br />

P1<br />

S 2<br />

P 2<br />

ACID/BASE<br />

pH = - log[H + ]<br />

[H + ]=10 -pH<br />

moles of solute<br />

kilograms of solvent<br />

<br />

Gas constant<br />

R 8.314 L kPa L atm L mmHg<br />

0.0821 62.4<br />

K mol K mol K mol<br />

1 atm = 760 mmHg = 760 torr = 101.3 kPa<br />

K = o C + 273<br />

o C = K - 273<br />

STP = Standard Temperature and Pressure = 0 o C<br />

and 1 atm<br />

P V<br />

1 1<br />

<br />

P2V<br />

2<br />

pOH = - log [OH - ]<br />

[OH - ]= 10 -pOH<br />

pH + pOH = 14<br />

Kw = [H + ] x [OH - ] = 1.0 x 10 -14 M 2<br />

V<br />

T<br />

1<br />

1<br />

P<br />

T<br />

1<br />

1<br />

V<br />

<br />

T<br />

P<br />

<br />

T<br />

2<br />

2<br />

2<br />

2<br />

Or V1T2 = V2T1<br />

Or P1T2 = P2T1<br />

THERMOCHEMISTRY<br />

ΔH= mCΔT, where ΔT = T f - T<br />

P1V<br />

1<br />

T<br />

1<br />

<br />

P2V<br />

2<br />

T<br />

2<br />

Or<br />

P1V1T2=P2V2T1<br />

q = mCΔT<br />

PV<br />

nRT<br />

Specific Heat of Water = 4.18 J/g*˚C or 1.0 cal/g*˚C<br />

Specific Heat of Ice = 2.1 J/g*˚C or 0.5 cal/g*˚C<br />

Specific Heat of Steam = 2.0 J/g*˚C or 0.4 cal/g*˚C<br />

P<br />

Total<br />

P<br />

1<br />

P<br />

2<br />

Rate A<br />

Rate B<br />

...<br />

<br />

Molar MassB<br />

Molar MassA<br />

R13


CHEMISTRY EXAM FORMULA AND RESOURCE PACKET<br />

Solubility of Compounds at 25 o C and 1 atm<br />

acetate<br />

bromide<br />

carbonate<br />

chlorate<br />

chloride<br />

hydroxide<br />

iodide<br />

nitrate<br />

oxide<br />

perchlorate<br />

phosphate<br />

sulfate<br />

sulfide<br />

aluminum S S - S S I S S I S I S d<br />

ammonium S S S S S S S S - S S S S<br />

barium S S I S S S S S sS S I I d<br />

calcium S S I S S S S S sS S I sS I<br />

copper(II) S S - S S I S S I S I S I<br />

iron(II) S S I S S I S S I S I S I<br />

iron(III) S S - S S I S S I S I sS d<br />

lithium S S sS S S S S S S S sS S S<br />

magnesium S S I S S I S S I S I S d<br />

potassium S S S S S S S S S S S S S<br />

silver sS I I S I - I S I S I sS I<br />

sodium S S S S S S S S S S S S S<br />

strontium S S I S S S S S S S I I I<br />

zinc S S I S S I S S I S I S I<br />

S=soluble<br />

sS = slightly soluble in water<br />

I = insoluble in water<br />

d = decomposes in water<br />

- = no such compound<br />

R14


CHEMISTRY EXAM FORMULA AND RESOURCE PACKET<br />

Common Polyatomic Ions<br />

1- Charge 2- Charge 3- Charge<br />

Formula Name Formula Name Formula Name<br />

Dihydrogen<br />

Phosphate<br />

Hydrogen<br />

phosphate<br />

Phosphite<br />

Acetate Oxalate Phosphate<br />

Hydrogen<br />

sulfite<br />

Sulfite<br />

Hydrogen<br />

sulfate<br />

Sulfate<br />

Hydrogen<br />

carbonate<br />

Carbonate<br />

Nitrite Chromate 1+ Charge<br />

Nitrate Dichromate Formula Name<br />

Cyanide Silicate Ammonium<br />

Hydroxide<br />

Permanganate<br />

Hypochlorite<br />

Chlorite<br />

Chlorate<br />

Perchlorate<br />

R15


Activity Series of Metals<br />

Name<br />

Symbol<br />

D<br />

Lithium<br />

Li<br />

e<br />

Potassium<br />

K<br />

c<br />

r<br />

Barium<br />

Ba<br />

e<br />

Calcium<br />

Ca<br />

a<br />

Sodium<br />

Na<br />

s<br />

i<br />

Magnesium<br />

Mg<br />

n<br />

Aluminum<br />

Al<br />

g<br />

Zinc<br />

Zn<br />

Iron<br />

Fe<br />

A<br />

c<br />

Nickel<br />

Ni<br />

t<br />

Tin<br />

Sn<br />

i<br />

v<br />

Lead<br />

Pb<br />

i<br />

(Hydrogen)<br />

(H)*<br />

t<br />

Copper<br />

Cu<br />

y<br />

Mercury<br />

Hg<br />

Silver<br />

Ag<br />

Gold<br />

Au<br />

*Metals from Li to Na will replace H from acids and water; from Mg to<br />

Pb they will replace H from acids only.<br />

Decreasing<br />

Activity<br />

Activity Series of Nonmetal (Halogens)<br />

Name<br />

Symbol<br />

Fluorine F 2<br />

Chlorine Cl 2<br />

Bromine Br 2<br />

Iodine I 2<br />

R16


Honors <strong>Chemistry</strong><br />

Class Policies and Grading<br />

The students will receive a Unit Outline at the beginning of each Unit. It will<br />

have information about the assignments that they will do, what it’s grade<br />

classification will be, what action they will need to do to complete the<br />

assignment and when it is due.<br />

The students will receive a Weekly Memo of the activities they will be<br />

responsible for that week. It will serve to inform the students of the learning<br />

goal for the week. It will also give the students any special information<br />

about that week.<br />

The students will also receive daily lectures and assignments that are<br />

designed to teach and re-enforce information related to the learning goal.<br />

This will be time in which new material will be taught and reviewed and will<br />

give the students the opportunity to ask questions regarding the concepts<br />

being taught.<br />

The students will work with a Lab partner and also be in a Lab group, but it<br />

will be up to the individual student to do his or her part of all assignments<br />

and the individual student will ultimately be responsible for all information<br />

presented in the class.<br />

The students will be required to follow all District and School Policies and to<br />

follow all Lab Safety Procedures, which they will be given and will sign,<br />

while performing labs. Students should come to class on time and with the<br />

supplies needed for that class.<br />

The following grading policy will be used.<br />

Assignment Categories<br />

<strong>Notebook</strong><br />

Test/Projects<br />

Labs/Quizzes<br />

Work<br />

The students will be given a teacher generated Mid Term and a District<br />

<strong>Final</strong>.


Unit 1<br />

Measurement Lab<br />

Separation of Mixtures Lab with Lab Write Up<br />

Unit 2<br />

Flame Test Lab<br />

Nuclear Decay Lab<br />

Element Marketing Project<br />

Unit 3<br />

Golden Penny Lab with Lab Write Up<br />

Molecular Geometry<br />

Research Presentation on a Chemical<br />

Mid Term<br />

Unit 4<br />

Double Displacement Lab<br />

Stoichiometry Lab with Lab Write Up<br />

Mole Educational Demonstration Project<br />

Unit 5<br />

Gas Laws Lab with Lab Write Up<br />

States of Matter Lab<br />

Teach a Gas Law Project<br />

Unit 6<br />

Dilutions Lab<br />

Titration Lab<br />

District <strong>Final</strong><br />

1


Unit 1 (22 days)<br />

Chapter 1 Introduction to <strong>Chemistry</strong><br />

Honors <strong>Chemistry</strong><br />

2017/2018 Syllabus<br />

3 days<br />

1.1 The Scope of <strong>Chemistry</strong> 1.3 Thinking Like a Scientist<br />

1.2 <strong>Chemistry</strong> and You 1.4 Problem Solving in <strong>Chemistry</strong><br />

Chapter 2 Matter and Change<br />

2.1 Properties of Matter 2.3 Elements and Compounds<br />

2.2 Mixtures 2.4 Chemical Reactions<br />

Chapter 3 Scientific Measurement<br />

9 days<br />

10 days<br />

3.1 Using and Expressing Measurements 3.3 Solving Conversion Problems<br />

3.2 Units of Measurement<br />

Unit 2 (15 days)<br />

Chapter 4 Atomic Structure<br />

5 days<br />

4.1 Defining the Atom 4.3 Distinguishing Among Atoms<br />

4.2 Structure of the Nuclear Atom<br />

Chapter 5 Electrons in Atoms<br />

5 days<br />

5.1 Revising the Atomic Model 5.2 Electron Arrangement in Atoms<br />

5.3 Atomic Emission Spectrum and the Quantum Mechanical Model<br />

Chapter 6 The Periodic Table<br />

6.1 Organizing the Elements 6.3 Periodic Trends<br />

6.2 Classifying Elements<br />

5 days<br />

Unit 3 (28 days)<br />

Chapter 25 Nuclear <strong>Chemistry</strong><br />

25.1 Nuclear Radiation 25.3 Fission and Fusion<br />

25.2 Nuclear Transformations 25.4 Radiation in Your Life<br />

Chapter 7 Ionic and Metallic Bonding<br />

7.1 Ions 7.3 Bonding in Metals<br />

7.2 Ionic Bonds and Ionic Compounds<br />

Chapter 8 Covalent Bonding<br />

6 days<br />

8 days<br />

8 days<br />

8.1 Molecular Compounds 8.3 Bonding Theories<br />

8.2 The Nature of Covalent Bonding 8.4 Polar Bonds and Molecules<br />

Chapter 9 Chemical Names and Formulas<br />

6 days<br />

9.1 Naming Ions 9.3 Naming & Writing Formulas Molecular Compounds<br />

9.2 Naming and Writing Formulas for Ionic Compounds 9.4 Names for Acids and Bases<br />

Unit 4 (8 days)<br />

Chapter 22 Hydrocarbons Compounds<br />

22.1 Hydrocarbons 22.4 Hydrocarbon Rings<br />

Chapter 23 Functional Groups<br />

4 days<br />

4 days<br />

23.1 Introduction to Functional Groups 23.4 Alcohols, Ethers, and Amines<br />

2


Unit 5 (28 days)<br />

Chapter 10 Chemical Quantities 8 days<br />

10.1 The Mole: A Measurement of Matter 10.3 % Composition & Chem. Formulas<br />

10.2 Mole-Mass and Mole-Volume Relationships<br />

Chapter 11 Chemical Reactions 8 days<br />

11.1 Describing Chemical Reactions 11.3 Reactions in Aqueous Solutions<br />

11.2 Types of Chemical Reactions<br />

Chapter 12 Stoichiometry 12 days<br />

12.1 The Arithmetic of Equations 12.3 Limiting Reagent and % Yield<br />

12.2 Chemical Calculations<br />

Unit 6 (22 days)<br />

Chapter 13 States of Matter 6 days<br />

13.1 The Nature of Gases 13.3 The Nature of Solids<br />

13.2 The Nature of Liquids 13.4 Changes in State<br />

Chapter 14 The Behavior of Gases 10 days<br />

14.1 Properties of Gases 14.3 Ideal Gases<br />

14.2 The Gas Laws 14.4 Gases: Mixtures and Movement<br />

Chapter 15 Water and Aqueous Systems 6 days<br />

15.1 Water and its Properties 15.3 Heterogeneous Aqueous Systems<br />

15.2 Homogeneous Aqueous Systems<br />

Unit 7 (18 days)<br />

Chapter 16 Solutions 8 days<br />

16.1 Properties of Solutions 16.3 Colligative Properties of Solutions<br />

16.2 Concentrations of Solutions 16.4 Calc. Involving Colligative Property<br />

Chapter 17 Thermochemistry 5 days<br />

17.1 The Flow of Energy 17.3 Heat in Changes of State<br />

17.2 Measuring and Expressing Enthalpy Change 17.4 Calculating Heats in Reactions<br />

Chapter 18 Reaction Rates and Equilibrium 5 days<br />

18.1 Rates of Reactions 18.3 Reversible Reaction & Equilibrium<br />

18.2 The Progress of Chemical Reactions 18.5 Free Energy and Entropy<br />

Unit 8 (14 days)<br />

Chapter 19 Acid and Bases 10 days<br />

19.1 Acid-Base Theories 19.4 Neutralization Reactions<br />

19.2 Hydrogen Ions and Acidity 19.5 Salts in Solutions<br />

19.3 Strengths of Acids and Bases<br />

Chapter 20 Oxidation-Reduction Reactions 4 days<br />

20.1 The Meaning of Oxidation and Reduction 20.3 Describing Redox Equations<br />

20.2 Oxidation Numbers<br />

3


Lorenzo Walker Technical High School<br />

MUSTANG LABORATORIES<br />

<strong>Chemistry</strong> Safety<br />

Safety in the MUSTANG LABORATORIES - <strong>Chemistry</strong> Laboratory<br />

Working in the chemistry laboratory is an interesting and rewarding experience. During your labs, you will be actively<br />

involved from beginning to end—from setting some change in motion to drawing some conclusion. In the laboratory, you<br />

will be working with equipment and materials that can cause injury if they are not handled properly.<br />

However, the laboratory is a safe place to work if you are careful. Accidents do not just happen; they are caused—by<br />

carelessness, haste, and disregard of safety rules and practices. Safety rules to be followed in the laboratory are listed<br />

below. Before beginning any lab work, read these rules, learn them, and follow them carefully.<br />

General<br />

1. Be prepared to work when you arrive at the lab. Familiarize yourself with the lab procedures before beginning the lab.<br />

2. Perform only those lab activities assigned by your teacher. Never do anything in the laboratory that is not called for in<br />

the laboratory procedure or by your teacher. Never work alone in the lab. Do not engage in any horseplay.<br />

3. Work areas should be kept clean and tidy at all times. Only lab manuals and notebooks should be brought to the work<br />

area. Other books, purses, brief cases, etc. should be left at your desk or placed in a designated storage area.<br />

4. Clothing should be appropriate for working in the lab. Jackets, ties, and other loose garments should be removed. Open<br />

shoes should not be worn.<br />

5. Long hair should be tied back or covered, especially in the vicinity of open flame.<br />

6. Jewelry that might present a safety hazard, such as dangling necklaces, chains, medallions, or bracelets should not be<br />

worn in the lab.<br />

7. Follow all instructions, both written and oral, carefully.<br />

8. Safety goggles and lab aprons should be worn at all times.<br />

9. Set up apparatus as described in the lab manual or by your teacher. Never use makeshift arrangements.<br />

10. Always use the prescribed instrument (tongs, test tube holder, forceps, etc.) for handling apparatus or equipment.<br />

11. Keep all combustible materials away from open flames.<br />

12. Never touch any substance in the lab unless specifically instructed to do so by your teacher.<br />

13. Never put your face near the mouth of a container that is holding chemicals.<br />

14. Never smell any chemicals unless instructed to do so by your teacher. When testing for odors, use a wafting motion to<br />

direct the odors to your nose.<br />

15. Any activity involving poisonous vapors should be conducted in the fume hood.<br />

16. Dispose of waste materials as instructed by your teacher.<br />

17. Clean up all spills immediately.<br />

18. Clean and wipe dry all work surfaces at the end of class. Wash your hands thoroughly.<br />

19. Know the location of emergency equipment (first aid kit, fire extinguisher, fire shower, fire blanket, etc.) and how to use them.<br />

20. Report all accidents to the teacher immediately.<br />

Handling Chemicals<br />

21. Read and double check labels on reagent bottles before removing any reagent. Take only as much reagent as you<br />

need.<br />

22. Do not return unused reagent to stock bottles.<br />

23. When transferring chemical reagents from one container to another, hold the containers out away from your body.<br />

24. When mixing an acid and water, always add the acid to the water.<br />

25. Avoid touching chemicals with your hands. If chemicals do come in contact with your hands, wash them immediately.<br />

26. Notify your teacher if you have any medical problems that might relate to lab work, such as allergies or asthma.<br />

27. If you will be working with chemicals in the lab, avoid wearing contact lenses. Change to glasses, if possible, or notify<br />

the teacher.<br />

Handling Glassware<br />

28. Glass tubing, especially long pieces, should be carried in a vertical position to minimize the likelihood of breakage and<br />

to avoid stabbing anyone.<br />

29. Never handle broken glass with your bare hands. Use a brush and dustpan to clean up broken glass. Dispose of the<br />

glass as directed by your teacher.<br />

4


30. Always lubricate glassware (tubing, thistle tubes, thermometers, etc.) with water or glycerin before attempting to insert<br />

it into a rubber stopper.<br />

31. Never apply force when inserting or removing glassware from a stopper. Use a twisting motion. If a piece of glassware<br />

becomes "frozen" in a stopper, take it to your teacher.<br />

32. Do not place hot glassware directly on the lab table. Always use an insulating pad of some sort.<br />

33. Allow plenty of time for hot glass to cool before touching it. Hot glass can cause painful burns. (Hot glass looks cool.)<br />

Heating Substances<br />

34. Exercise extreme caution when using a gas burner. Keep your head and clothing away from the flame.<br />

35. Always turn the burner off when it is not in use.<br />

36. Do not bring any substance into contact with a flame unless instructed to do so.<br />

37. Never heat anything without being instructed to do so.<br />

38. Never look into a container that is being heated.<br />

39. When heating a substance in a test tube, make sure that the mouth of the tube is not pointed at yourself or anyone<br />

else.<br />

40. Never leave unattended anything that is being heated or is visibly reacting.<br />

First Aid in the MUSTANG LABORATORIES - <strong>Chemistry</strong> Laboratory<br />

Accidents do not often happen in well-equipped chemistry laboratories if students understand safe laboratory procedures<br />

and are careful in following them. When an occasional accident does occur, it is likely to be a minor one.<br />

The instructor will assist in treating injuries such as minor cuts and burns. However, for some types of injuries, you must<br />

take action immediately. The following information will be helpful to you if an accident occurs.<br />

1. Shock. People who are suffering from any severe injury (for example, a bad burn or major loss of blood) may be in a<br />

state of shock. A person in shock is usually pale and faint. The person may be sweating, with cold, moist skin and a weak,<br />

rapid pulse. Shock is a serious medical condition. Do not allow a person in shock to walk anywhere—even to the campus<br />

security office. While emergency help is being summoned, place the victim face up in a horizontal position, with the feet<br />

raised about 30 centimeters. Loosen any tightly fitting clothing and keep him or her warm.<br />

2. Chemicals in the Eyes. Getting any kind of a chemical into the eyes is undesirable, but certain chemicals are<br />

especially harmful. They can destroy eyesight in a matter of seconds. Because you will be wearing safety goggles at all<br />

times in the lab, the likelihood of this kind of accident is remote. However, if it does happen, flush your eyes with water<br />

immediately. Do NOT attempt to go to the campus office before flushing your eyes. It is important that flushing with water<br />

be continued for a prolonged time—about 15 minutes.<br />

3. Clothing or Hair on Fire. A person whose clothing or hair catches on fire will often run around hysterically in an<br />

unsuccessful effort to get away from the fire. This only provides the fire with more oxygen and makes it burn faster. For<br />

clothing fires, throw yourself to the ground and roll around to extinguish the flames. For hair fires, use a fire blanket to<br />

smother the flames. Notify campus security immediately.<br />

4. Bleeding from a Cut. Most cuts that occur in the chemistry laboratory are minor. For minor cuts, apply pressure to the<br />

wound with a sterile gauze. Notify campus security of all injuries in the lab. If the victim is bleeding badly, raise the<br />

bleeding part, if possible, and apply pressure to the wound with a piece of sterile gauze. While first aid is being given,<br />

someone else should notify the campus security officer.<br />

5. Chemicals in the Mouth. Many chemicals are poisonous to varying degrees. Any chemical taken into the mouth<br />

should be spat out and the mouth rinsed thoroughly with water. Note the name of the chemical and notify the campus<br />

office immediately. If the victim swallows a chemical, note the name of the chemical and notify campus security<br />

immediately.<br />

If necessary, the campus security officer or administrator will contact the Poison Control Center, a hospital emergency<br />

room, or a physician for instructions.<br />

6. Acid or Base Spilled on the Skin.<br />

Flush the skin with water for about 15 minutes. Take the victim to the campus office to report the injury.<br />

7. Breathing Smoke or Chemical Fumes.<br />

All experiments that give off smoke or noxious gases should be conducted in a well-ventilated fume hood. This will make<br />

an accident of this kind unlikely. If smoke or chemical fumes are present in the laboratory, all persons—even those who<br />

do not feel ill—should leave the laboratory immediately. Make certain that all doors to the laboratory are closed after the<br />

last person has left. Since smoke rises, stay low while evacuating a smoke-filled room. Notify campus security<br />

immediately.<br />

5


6<br />

MUSTANG LABORATORIES<br />

COMMITMENT TO SAFETY IN THE LABORATORY<br />

As a student enrolled in <strong>Chemistry</strong> at Lorenzo Walker Technical High<br />

School, I agree to use good laboratory safety practices at all times. I<br />

also agree that I will:<br />

1. Conduct myself in a professional manner, respecting both my personal safety and the safety of<br />

others in the laboratory.<br />

2. Wear proper and approved safety glasses or goggles in the laboratory at all times.<br />

3. Wear sensible clothing and tie back long hair in the laboratory. Understand that open-toed shoes<br />

pose a hazard during laboratory classes and that contact lenses are an added safety risk.<br />

4. Keep my lab area free of clutter during an experiment.<br />

5. Never bring food or drink into the laboratory, nor apply makeup within the laboratory.<br />

6. Be aware of the location of safety equipment such as the fire extinguisher, eye wash station, fire<br />

blanket, first aid kit. Know the location of the nearest telephone and exits.<br />

7. Read the assigned lab prior to coming to the laboratory.<br />

8. Carefully read all labels on all chemical containers before using their contents, remove a small<br />

amount of reagent properly if needed, do not pour back the unused chemicals into the original<br />

container.<br />

9. Dispose of chemicals as directed by the instructor only. At no time will I pour anything down the<br />

sink without prior instruction.<br />

10. Never inhale fumes emitted during an experiment. Use the fume hood when instructed to do so.<br />

11. Report any accident immediately to the instructor, including chemical spills.<br />

12. Dispose of broken glass and sharps only in the designated containers.<br />

13. Clean my work area and all glassware before leaving the laboratory.<br />

14. Wash my hands before leaving the laboratory.<br />

NAME __________________________<br />

Emisael Vega<br />

PERIOD ________________________<br />

5<br />

Veronica Avila<br />

PARENT NAME ____________________________<br />

PARENT NUMBER _________________________<br />

239-200-2336<br />

SIGNATURE ____________________________<br />

DATE ____________________________________<br />

8/17/17


7


Chapter 1<br />

Unit 1<br />

Introduction to <strong>Chemistry</strong><br />

The students will learn why and how to solve problems using<br />

chemistry.<br />

Identify what is science, what clearly is not science, and what superficially<br />

resembles science (but fails to meet the criteria for science).<br />

Students will identify a phenomenon as science or not science.<br />

Science<br />

Observation<br />

Inference<br />

Hypothesis<br />

Identify which questions can be answered through science and which<br />

questions are outside the boundaries of scientific investigation, such as<br />

questions addressed by other ways of knowing, such as art, philosophy, and<br />

religion.<br />

Students will differentiate between problems and/or phenomenon that can and<br />

those that cannot be explained or answered by science.<br />

Students will differentiate between problems and/or phenomenon that can and<br />

those that cannot be explained or answered by science.<br />

Observation<br />

Inference<br />

Hypothesis<br />

Theory<br />

Controlled experiment<br />

Describe how scientific inferences are drawn from scientific observations<br />

and provide examples from the content being studied.<br />

Students will conduct and record observations.<br />

Students will make inferences.<br />

Students will identify a statement as being either an observation or inference.<br />

Students will pose scientific questions and make predictions based on<br />

inferences.<br />

Inference<br />

Observation<br />

Hypothesis<br />

Controlled experiment<br />

Identify sources of information and assess their reliability according to the<br />

strict standards of scientific investigation.<br />

Students will compare and assess the validity of known scientific information<br />

from a variety of sources:<br />

8


Print vs. print<br />

Online vs. online<br />

Print vs. online<br />

Students will conduct an experiment using the scientific method and compare<br />

with other groups.<br />

Controlled experiment<br />

Investigation<br />

Peer Review<br />

Accuracy<br />

Precision<br />

Percentage Error<br />

Chapter 2<br />

Matter and Change<br />

The students will learn what properties are used to describe<br />

matter and how matter can change its form.<br />

Differentiate between physical and chemical properties and physical and<br />

chemical changes of matter.<br />

Students will be able to identify physical and chemical properties of various<br />

substances.<br />

Students will be able to identify indicators of physical and chemical changes.<br />

Students will be able to calculate density.<br />

mass<br />

physical property<br />

volume<br />

chemical property<br />

vapor<br />

extensive property<br />

Chapter 3<br />

mixture<br />

intensive property<br />

solution<br />

element<br />

compound<br />

Scientific Measurements<br />

The students will be able to solve conversion problems using<br />

measurements.<br />

Determine appropriate and consistent standards of measurement for the<br />

data to be collected in a survey or experiment.<br />

Students will participate in activities to collect data using standardized<br />

measurement.<br />

Students will be able to manipulate/convert data collected and apply the data<br />

to scientific situations.<br />

Scientific notation<br />

International System of Units (SI)<br />

Significant figures<br />

Accepted value<br />

Experimental value<br />

Percent error<br />

Dimensional analysis<br />

9


The Learning Goal for this assignment is:<br />

Determine appropiate and consistent standard of measurement for the data to be collected in a survey or experiment.<br />

Notes Section<br />

King Kilo (1000) hecto (100) Deca (10) Base (base meter gram liter) Deci (1/10, .1) Centi (1/100, .01) Mini (1/1000, .001)<br />

Henry<br />

Died<br />

By<br />

Drinking<br />

Choclate<br />

Milk<br />

You get the measurment of the another types by diving them by 10.<br />

The metric sytem measures based on multiples of ten. The prefix are used to show what multiples ten base unit is bieng<br />

multiplied by.<br />

Example<br />

Convert 1600 cm into meters<br />

You but a decimal point in the end of your number if your moving to the left<br />

1600.<br />

Then you move it to decimal points. Because of the metric sytem meter is 2 left away.<br />

16.00<br />

your awnser would be 16 meters.<br />

Convert 11 Dm into ml<br />

1. You put a decimal point in front cause your going to be moving to right.<br />

.11<br />

2. Then you move the decimal point. Because of the metric system you move it right 4 becuse its away from it<br />

1100.<br />

3. After you move the decimal point you ge your answer wich is 1100 ML<br />

Convert 756 ml into k<br />

1. Decimal point is put in the end because your going to be moving left.<br />

756.<br />

2. you move the point 6 to the left because thats how far away it is.<br />

.000756<br />

3. after you move the point you get your answer .000756 K<br />

All in all that i learned from metric conversions is that i was overthinking every thing. I learned it was quite simple all that<br />

is required iin order to do coversition was count to 6 and know right and left.<br />

10


11<br />

To use the Stair-Step method, find the prefix the original measurement starts with. (ex. milligram)<br />

If there is no prefix, then you are starting with a base unit.<br />

Find the step which you wish to make the conversion to. (ex. decigram)<br />

Count the number of steps you moved, and determine in which direction you moved (left or right).<br />

The decimal in your original measurement moves the same number of places as steps you moved and in the<br />

same direction. (ex. milligram to decigram is 2 steps to the left, so 40 milligrams = .40 decigrams)<br />

If the number of steps you move is larger than the number you have, you will have to add zeros to hold the<br />

places. (ex. kilometers to meters is three steps to the right, so 10 kilometers would be equal to 10,000 m)<br />

That’s all there is to it! You need to be able to count to 6, and know your left from your right!<br />

1) Write the equivalent<br />

a) 5 dm =_______m .5 b) 4 mL = .004 ______L c) 8 g = _______mg<br />

8000.<br />

d) 9 mg =_______g .009 e) 2 mL = ______L .002 f) 6 kg = _____g 6000<br />

g) 4 cm =_______m .04 h) 12 mg = ______ .012 g i) 6.5 cm 3 = _______L .0065<br />

j) 7.02 mL =_____cm 7.02 3 k) .03 hg = _______ 30 dg l) 6035 mm _____cm 603.5<br />

m) .32 m = _______cm 32 n) 38.2 g = .0382 _____kg


2. One cereal bar has a mass of 37 g. What is the mass of 6 cereal bars? Is that more than or less<br />

than 1 kg? Explain your answer.<br />

The mass of 6 cereal box is a total of 222 grams. Wen converted to kg it is .222.<br />

It is less than half a kilogram.<br />

3. Wanda needs to move 110 kg of rocks. She can carry l0 hg each trip. How many trips must she<br />

make? Explain your answer.<br />

When 10 hecto grams is converted to kilograms it is 1 . Which means that it would take her 110 trips .<br />

4. Dr. O is playing in her garden again She needs 1 kg of potting soil for her plants. She has 750 g.<br />

How much more does she need? Explain your answer.<br />

When you convert 750 g you get 0.75 kg which means she will need .25 kg to get to a kilo or 250 g<br />

5. Weather satellites orbit Earth at an altitude of 1,400,000 meters. What is this altitude in kilometers?<br />

The altitude in kilometers would be 1400 km .<br />

6. Which unit would you use to measure the capacity? Write milliliter or liter.<br />

a) a bucket __________<br />

Liter<br />

b) a thimble __________<br />

Milliliter<br />

c) a water storage tank__________ LIter<br />

d) a carton of juice__________<br />

Milliliter<br />

7. Circle the more reasonable measure:<br />

a) length of an ant 5mm or 5cm<br />

b) length of an automobile 5 m or 50 m<br />

c) distance from NY to LA 450 km or 4,500 km<br />

d) height of a dining table 75 mm or 75 cm<br />

8. Will a tablecloth that is 155 cm long cover a table that is 1.6 m long? Explain your answer.<br />

The table cloth that is 155 cm long cannot cover because its 1.55 meters long its .05 meter short.<br />

9. A dollar bill is 15.6 cm long. If 200 dollar bills were laid end to end, how many meters long would<br />

the line be?<br />

First you multiply 15.6 times two hundred it is 3120 than converted it would be 31.2 meters long<br />

10. The ceiling in Jan’s living room is 2.5 m high. She has a hanging lamp that hangs down 41 cm.<br />

Her husband is exactly 2 m tall. Will he hit his head on the hanging lamp? Why or why not?<br />

No because the room is 250 cm then we take 41 away and are left with 209 cm. And her husband is 200 cm and<br />

Thier is 9cm in between so he wont hit the lamp.<br />

12


Using SI Units<br />

Match the terms in Column II with the descriptions in Column I. Write the letters of the correct term in<br />

the blank on the left.<br />

Column I Column II<br />

_____ k 1. distance between two points<br />

a. time<br />

_____ e 2. SI unit of length<br />

_____ m 3. tool used to measure length<br />

_____ g 4. units obtained by combining other units<br />

_____ b 5. amount of space occupied by an object<br />

_____ b 6. unit used to express volume<br />

_____ h 7. SI unit of mass<br />

_____ c 8. amount of matter in an object<br />

_____ d 9. mass per unit of volume<br />

_____ o 10. temperature scale of most laboratory thermometers<br />

_____ 1 11. instrument used to measure mass<br />

_____ a 12. interval between two events<br />

_____ j 13. SI unit of temperature<br />

_____ i 14. SI unit of time<br />

_____ n 15. instrument used to measure temperature<br />

b. volume<br />

c. mass<br />

d. density<br />

e. meter<br />

f. kilogram<br />

g. derived<br />

h. liter<br />

i. second<br />

j. Kelvin<br />

k. length<br />

1. balance<br />

m. meterstick<br />

n. thermometer<br />

o. Celsius<br />

Circle the two terms in each group that are related. Explain how the terms are related.<br />

16. Celsius degree, mass, Kelvin _____________________________________________________<br />

The two terms that are related are Celsius degree and kelvin because they<br />

________________________________________________________________________________<br />

both have to do with temperature.<br />

17. balance, second, mass __________________________________________________________<br />

The two terms that are related are balance and mass becuase they are both<br />

________________________________________________________________________________<br />

dealing with mass and wieght.<br />

18. kilogram, liter, cubic centimeter __________________________________________________<br />

The two that are similar are liter and cubic centimeters because they<br />

________________________________________________________________________________<br />

both have to do with volume.<br />

19. time, second, distance __________________________________________________________<br />

The two that are alike are time and seconds becuse sneconds is part of time.<br />

________________________________________________________________________________<br />

20. decimeter, kilometer, Kelvin _____________________________________________________<br />

The two that are related are decimeter and kilometere because they<br />

________________________________________________________________________________<br />

have to do with distances and can be converted to one another.<br />

13


1. How many meters are in one kilometer? __________<br />

1000<br />

2. What part of a liter is one milliliter? __________<br />

.001<br />

3. How many grams are in two dekagrams? __________<br />

20<br />

4. If one gram of water has a volume of one milliliter, what would the mass of one liter of water be in<br />

kilograms?__________<br />

1<br />

5. What part of a meter is a decimeter? __________ 0.1<br />

In the blank at the left, write the term that correctly completes each statement. Choose from the terms<br />

listed below.<br />

Metric SI standard ten<br />

prefixes ten tenth<br />

6. An exact quantity that people agree to use for comparison is a ______________ Standard ten .<br />

7. The system of measurement used worldwide in science is _______________ SI<br />

.<br />

8. SI is based on units of _______________ Ten<br />

.<br />

9. The system of measurement that was based on units of ten was the _______________ Metric system.<br />

10. In SI, _______________ Prefixes are used with the names of the base unit to indicate the multiple of ten<br />

that is being used with the base unit.<br />

11. The prefix deci- means _______________ tenth<br />

.<br />

14


Standards of Measurement<br />

Fill in the missing information in the table below.<br />

S.I prefixes and their meanings<br />

Prefix<br />

Meaning<br />

0.001<br />

0.01<br />

deci- 0.1<br />

10<br />

hecto- 100<br />

1000<br />

Circle the larger unit in each pair of units.<br />

1. millimeter, kilometer 4. centimeter, millimeter<br />

2. decimeter, dekameter 5. hectogram, kilogram<br />

3. hectogram, decigram<br />

6. In SI, the base unit of length is the meter. Use this information to arrange the following units of<br />

measurement in the correct order from smallest to largest.<br />

Write the number 1 (smallest) through 7 - (largest) in the spaces provided.<br />

_____ 7 a. kilometer<br />

_____ 2 b. centimeter<br />

_____ 4 c. meter<br />

_____ 6 e. hectometer<br />

_____ 1 f. millimeter<br />

_____ 3 g. decimeter<br />

_____ 5 d. dekameter<br />

Use your knowledge of the prefixes used in SI to answer the following questions in the spaces<br />

provided.<br />

7. One part of the Olympic games involves an activity called the decathlon. How many events do you<br />

think make up the decathlon?_____________________________________________________<br />

I think its ten because means 10.<br />

8. How many years make up a decade? _______________________________________________<br />

Ten years make a decade. 10<br />

9. How many years make up a century? ______________________________________________<br />

Hundred years make a century. 100<br />

10. What part of a second do you think a millisecond is? __________________________________<br />

its .001<br />

15


The Learning Goal for this assignment is:<br />

Determine approriate and consistent standards of measurements for the data to be collected in a survey or expirement.<br />

Notes Section<br />

You find the mass of an object by weighing it in balance.<br />

In order to get density you have to divide mass by volume.<br />

Density= mass/ volume<br />

Ex: Density = 45g/15cm^3 = 3.0 g/cm^3 this means grams per cubic centimeters.<br />

K H D B d C M<br />

1000 100 10 1 1 .01 .001<br />

10^3 10^2 10^1 10^0 10^-1 10^-2 10^-3<br />

Scientifc Notation<br />

N x 10 ^b<br />

N= Any number between 1 and 10.<br />

A= An exponent can be negative or postive.<br />

Examples;<br />

1687<br />

First you have to move the decimal point over three because the n numer is the one that we are looking for.<br />

1.687<br />

Then you no that it its always going t be multiplies to the tenth.<br />

1.687x 10<br />

Then you will put -3 becasue you moved it 3 times to the left which makes it postive 3.<br />

<strong>Final</strong> awnser:<br />

1.687 x 10^3<br />

Example;<br />

3.5 x 10 ^-4<br />

The awnser will be 0.00035 .<br />

The reason that it is negative exponent you have to move the decimal point to the left 3 .<br />

1. 7,485 6. 1.683<br />

2. 884.2 7. 3.622<br />

3. 0.00002887 8. 0.00001735<br />

4. 0.05893 9. 0.9736<br />

5. 0.006162 10. 0.08558<br />

11. 6.633 X 10−⁴ 16. 1.937 X 10⁴<br />

12. 4.445 X 10−⁴ 17. 3.457 X 10⁴<br />

13. 2.182 X 10−³ 18. 3.948 X 10−⁵<br />

14. 4.695 X 10² 19. 8.945 X 10⁵<br />

15. 7.274 X 10⁵ 20. 6.783 X 10²<br />

16


SCIENTIFIC NOTATION RULES<br />

How to Write Numbers in Scientific Notation<br />

Scientific notation is a standard way of writing very large and very small numbers so that they're<br />

easier to both compare and use in computations. To write in scientific notation, follow the form<br />

N X 10 ᴬ<br />

where N is a number between 1 and 10, but not 10 itself, and A is an integer (positive or negative<br />

number).<br />

RULE #1: Standard Scientific Notation is a number from 1 to 9 followed by a decimal and the<br />

remaining significant figures and an exponent of 10 to hold place value.<br />

Example:<br />

5.43 x 10 2 = 5.43 x 100 = 543<br />

8.65 x 10 – 3 = 8.65 x .001 = 0.00865<br />

****54.3 x 10 1 is not Standard Scientific Notation!!!<br />

RULE #2: When the decimal is moved to the Left the exponent gets Larger, but the value of the<br />

number stays the same. Each place the decimal moves Changes the exponent by one (1). If you<br />

move the decimal to the Right it makes the exponent smaller by one (1) for each place it is moved.<br />

Example:<br />

6000. x 10 0 = 600.0 x 10 1 = 60.00 x 10 2 = 6.000 x 10 3 = 6000<br />

(Note: 10 0 = 1)<br />

All the previous numbers are equal, but only 6.000 x 10 3 is in proper Scientific Notation.<br />

17


RULE #3: To add/subtract in scientific notation, the exponents must first be the same.<br />

Example:<br />

(3.0 x 10 2 ) + (6.4 x 10 3 ); since 6.4 x 10 3 is equal to 64. x 10 2 . Now add.<br />

(3.0 x 10 2 )<br />

+ (64. x 10 2 )<br />

67.0 x 10 2 = 6.70 x 10 3 = 6.7 x 10 3<br />

67.0 x 10 2 is mathematically correct, but a number in standard scientific notation can only<br />

have one number to the left of the decimal, so the decimal is moved to the left one place and<br />

one is added to the exponent.<br />

Following the rules for significant figures, the answer becomes 6.7 x 10 3 .<br />

RULE #4: To multiply, find the product of the numbers, then add the exponents.<br />

Example:<br />

(2.4 x 10 2 ) (5.5 x 10 –4 ) = ? [2.4 x 5.5 = 13.2]; [2 + -4 = -2], so<br />

(2.4 x 10 2 ) (5.5 x 10 –4 ) = 13.2 x 10 –2 = 1.3 x 10 – 1<br />

RULE #5: To divide, find the quotient of the number and subtract the exponents.<br />

Example:<br />

(3.3 x 10 – 6 ) / (9.1 x 10 – 8 ) = ? [3.3 / 9.1 = .36]; [-6 – (-8) = 2], so<br />

(3.3 x 10 – 6 ) / (9.1 x 10 – 8 ) = .36 x 10 2 = 3.6 x 10 1<br />

18


Convert each number from Scientific Notation to real numbers:<br />

1. 7.485 X 10³ 6. 1.683 X 10⁰<br />

7458<br />

1.683<br />

2. 8.842 X 10² 7. 3.622 10⁰<br />

884.2<br />

3.622<br />

3. 2.887 X 10−⁵ 8. 1.735 X 10−⁵<br />

0.00002887<br />

0.00001735<br />

4. 5.893 X 10−² 9. 9.736 X 10−¹<br />

0.05893<br />

0.9736<br />

5. 6.162 X 10−³ 10. 8.558 X 10−²<br />

0.006162 0.08558<br />

Convert each number from a real number to Scientific Notation:<br />

11. 0.0006633 16. 1,937,000<br />

6.633 x^-4<br />

1.937 x 10^6<br />

12. 0.0004445 17. 34,570<br />

4.445 x 10^-4<br />

3.457 x 10^-4<br />

13. 0.002182 18. 0.00003948<br />

2.182 x 10^-3<br />

3.948 x 10^-8<br />

14. 469.5 19. 894,500<br />

4.695 x 10^2<br />

8.948 x 10^5<br />

15. 727,400 20. 678.3<br />

7.274 x 10^5<br />

6.783 x 10^2<br />

19


The Learning Goal for this assignment is:<br />

Determine appropriate and consistent standards of measurement for the data to be collected in a survey or expirement.<br />

Notes Section:<br />

Significant figures<br />

1. non zero digits are always significant<br />

Examples:<br />

1 2 3 4 5 6 7 8 9 are significant numbers<br />

2.Any zero between two significant digits are significant.<br />

Examples ;<br />

101 has 3 significant zeros.<br />

8604 has 44 significant numbers .<br />

13.068 has 5 significant numbers.<br />

8670 only 3 signifcant numbers because of rule number one.<br />

3. A final zero or trailing zeros in the Decimal Portion Only are significant<br />

Examples;<br />

45.60 has 4 significant numbers becasue of rule number 3.<br />

.870 has 3 significant numbers because the zero is after decimal.<br />

.10060 it has 5 significant rules because of the thir rule<br />

Zeros are not significantunless thier is decimal point is not the firts after the decimal but in middle or end only with decimal.<br />

The diffrence between precision and acuarcy the decimal point is longer the number is much more Precise.<br />

When it comes adiition and subtraction figs you have to round the least number of place in the decimal<br />

portion of any number in the portion.<br />

Question Sig Figs Question Add & Subtract Question Multiple & Divide<br />

1 4 1 55.36 1 20,000<br />

2 4 2 84.2 2 94<br />

3 3 3 115.4 3 300<br />

4 3 4 0.8 4 7<br />

5 4 5 245.53 5 62<br />

6 3 6 34.5 6 0.005<br />

7 3 7 74.0 7 4,000<br />

8 2 8 53.287 8 3,900,000<br />

9 2 9 54.876 9 2<br />

10 2 10 40.19 10 30,000,000<br />

11 3 11 7.7 11 1,200<br />

12 2 12 67.170 12 0.2<br />

13 3 13 81.0 13 0.87<br />

14 4 14 73.290 14 0.049<br />

15 4 15 29.789 15 2,000<br />

16 3 16 39.53 16 0.5<br />

17 4 17 70.58 17 1.9<br />

18 2 18 86.6 18 0.05<br />

19 2 19 64.990 19 230<br />

20 1 20 36.0 20 460,000<br />

20


Significant Figures Rules<br />

There are three rules on determining how many significant figures are in a<br />

number:<br />

1. Non-zero digits are always significant.<br />

2. Any zeros between two significant digits are significant.<br />

3. A final zero or trailing zeros in the DECIMAL PORTION ONLY are<br />

significant.<br />

Please remember that, in science, all numbers are based upon measurements (except for a very few<br />

that are defined). Since all measurements are uncertain, we must only use those numbers that are<br />

meaningful.<br />

Not all of the digits have meaning (significance) and, therefore, should not be written down. In<br />

science, only the numbers that have significance (derived from measurement) are written.<br />

Rule 1: Non-zero digits are always significant.<br />

If you measure something and the device you use (ruler, thermometer, triple-beam, balance, etc.)<br />

returns a number to you, then you have made a measurement decision and that ACT of measuring<br />

gives significance to that particular numeral (or digit) in the overall value you obtain.<br />

Hence a number like 46.78 would have four significant figures and 3.94 would have three.<br />

Rule 2: Any zeros between two significant digits are significant.<br />

Suppose you had a number like 409. By the first rule, the 4 and the 9 are significant. However, to<br />

make a measurement decision on the 4 (in the hundred's place) and the 9 (in the one's place), you<br />

HAD to have made a decision on the ten's place. The measurement scale for this number would have<br />

hundreds, tens, and ones marked.<br />

Like the following example:<br />

These are sometimes called "captured zeros."<br />

If a number has a decimal at the end (after the one’s place) then all digits (numbers) are significant<br />

and will be counted.<br />

In the following example the zeros are significant digits and highlighted in blue.<br />

960.<br />

70050.<br />

21


Rule 3: A final zero or trailing zeros in the decimal portion ONLY are<br />

significant.<br />

This rule causes the most confusion among students.<br />

In the following example the zeros are significant digits and highlighted in blue.<br />

0.07030<br />

0.00800<br />

Here are two more examples where the significant zeros are highlighted in blue.<br />

When Zeros are Not Significant Digits<br />

4.7 0 x 10−³<br />

6.5 0 0 x 10⁴<br />

Zero Type # 1 : Space holding zeros in numbers less than one.<br />

In the following example the zeros are NOT significant digits and highlighted in red.<br />

0.09060<br />

0.00400<br />

These zeros serve only as space holders. They are there to put the decimal point in its correct<br />

location.<br />

They DO NOT involve measurement decisions.<br />

Zero Type # 2 : Trailing zeros in a whole number.<br />

In the following example the zeros are NOT significant digits and highlighted in red.<br />

200<br />

25000<br />

For addition and subtraction, look at the decimal portion (i.e., to the right of the decimal point)<br />

of the numbers ONLY. Here is what to do:<br />

1) Count the number of significant figures in the decimal portion of each number in the problem. (The<br />

digits to the left of the decimal place are not used to determine the number of decimal places in the<br />

final answer.)<br />

2) Add or subtract in the normal fashion.<br />

3) Round the answer to the LEAST number of places in the decimal portion of any number in the<br />

problem<br />

The following rule applies for multiplication and division:<br />

The LEAST number of significant figures in any number of the problem determines the number of<br />

significant figures in the answer.<br />

This means you MUST know how to recognize significant figures in order to use this rule.<br />

22


How Many Significant Digits for Each Number?<br />

1) 2359 = ______ 4<br />

2) 2.445 x 10−⁵= ______ 4<br />

3) 2.93 x 10⁴= ______ 3<br />

4) 1.30 x 10−⁷= ______ 3<br />

5) 2604 = ______ 4<br />

6) 9160 = ______ 3<br />

7) 0.0800 = ______ 3<br />

8) 0.84 = ______ 2<br />

9) 0.0080 = ______ 2<br />

10) 0.00040 = ______ 2<br />

11) 0.0520 = ______ 3<br />

12) 0.060 = ______ 2<br />

13) 6.90 x 10−¹= ______ 3<br />

14) 7.200 x 10⁵= ______ 2<br />

15) 5.566 x 10−²= ______ 4<br />

16) 3.88 x 10⁸= ______ 3<br />

17) 3004 = ______ 4<br />

18) 0.021 = ______ 2<br />

19) 240 = ______ 2<br />

20) 500 = ______ 1<br />

23


For addition and subtraction, look at the decimal portion (i.e., to the right of the decimal point) of the<br />

numbers ONLY. Here is what to do:<br />

1) Count the number of significant figures in the decimal portion of each number in the problem. (The<br />

digits to the left of the decimal place are not used to determine the number of decimal places in the<br />

final answer.)<br />

2) Add or subtract in the normal fashion.<br />

3) Round the answer to the LEAST number of places in the decimal portion of any number in the<br />

problem.<br />

Solve the Problems and Round Accordingly...<br />

1) 43.287 + 5.79 + 6.284 = _______ 55.36<br />

55.361<br />

2) 87.54 - 3.3 = _______ 84.2 84.24<br />

3) 99.1498 + 6.5397 + 9.7 = _______ 115.4 115.3895<br />

4) 5.868 - 5.1 = _______ .8 .768<br />

5) 59.9233 + 86.21 + 99.396 = _______ 245.53<br />

245.5293<br />

6) 7.7 + 26.756 = _______ 34.5<br />

34.4366<br />

7) 66.8 + 2.3 + 4.8516 = _______ 74.0 73.951<br />

8) 9.7419 + 43.545 = _______ 53.287<br />

53.2869<br />

9) 4.8976 + 48.4644 + 1.514 = _______ 54.876<br />

54.876<br />

10) 4.335 + 35.85 = _______ 40.19 40.185<br />

11) 9.448 - 1.7 = _______ 7.7<br />

12) 75.826 - 8.6555 = _______ 67.170<br />

13) 57.2 + 23.814 = _______<br />

81.0<br />

14) 77.684 - 4.394 = _______ 73.290<br />

7.748<br />

67.1705<br />

81.014<br />

73.290<br />

15) 26.4496 + 3.339 = _______ 29.789<br />

16) 9.6848 + 29.85 = _______ 39.53<br />

29.7886<br />

39.5348<br />

17) 63.11 + 2.5412 + 4.93 = _______ 70.58<br />

18) 11.2471 + 75.4 = _______ 86.6<br />

19) 73.745 - 8.755 = _______ 64.990<br />

20) 6.5238 + 1.7 + 27.79 = _______ 36.0<br />

86.6471<br />

70.5812<br />

64.990<br />

36.0138<br />

24


25<br />

The following rule applies for multiplication and division:<br />

The LEAST number of significant figures in any number of the problem determines the number of<br />

significant figures in the answer.<br />

This means you MUST know how to recognize significant figures in order to use this rule.<br />

Solve the Problems and Round Accordingly...<br />

1) 0.6 x 65.0 x 602 = __________<br />

20000<br />

23478<br />

2) 720 ÷ 7.7 = __________<br />

94<br />

300<br />

3) 929 x 0.3 = __________<br />

4) 300 ÷ 44.31 = __________<br />

62<br />

5) 608 ÷ 9.8 = __________<br />

6) 0.06 x 0.079 = __________<br />

7<br />

.005<br />

93.50649351<br />

278.7<br />

6.770480704<br />

62.04081633<br />

.00474<br />

7) 0.008 x 72.91 x 7000 = __________<br />

4000<br />

3900000<br />

8) 73.94 x 67 x 780 = __________<br />

9) 0.62 x 0.097 x 40 = __________<br />

2<br />

10) 600 x 10 x 5030 = __________<br />

30000000<br />

4082.96<br />

3864104.4<br />

2.4056<br />

30180000<br />

11) 5200 ÷ 4.46 = __________<br />

1200<br />

1165.919283<br />

12) 0.0052 x 0.4 x 107 = __________<br />

0.2<br />

0.87<br />

13) 0.099 x 8.8 = __________<br />

0.049<br />

14) 0.0095 x 5.2 = __________<br />

1200<br />

15) 8000 ÷ 4.62 = __________<br />

0.22256<br />

0.8712<br />

0.0494<br />

1731.601732<br />

0.05<br />

16) 0.6 x 0.8 = __________<br />

17) 2.84 x 0.66 = __________<br />

1.9<br />

0.05<br />

18) 0.5 x 0.09 = __________<br />

19) 8100 ÷ 34.84 = __________<br />

230<br />

0.48<br />

1.8744<br />

0.045<br />

234.9187935<br />

20) 8.24 x 6.9 x 8100 = __________<br />

460000<br />

460533.6


Dimensional Analysis<br />

This is a way to convert from one unit of a given substance to<br />

another unit using ratios or conversion units. What this video<br />

www.youtube.com/watch?v=aZ3J60GYo6U<br />

Let’ look at a couple of examples:<br />

1. Convert 2.6 qt to mL.<br />

First we need a ratio or conversion unit so that we can go from quarts to milliliters. 1.00 qt = 946 mL<br />

Next write down what you are starting with<br />

2.6 qt<br />

Then make you conversion tree<br />

2.6 qt<br />

Then fill in the units in your ratio so that you can cancel out the original unit and will be left with the<br />

unit you need for the answer. Cross out units, one at a time that are paired, and one on top one on<br />

the bottom.<br />

2.6 qt mL<br />

qt<br />

Now fill in the values from the ratio.<br />

2.6 qt 946 mL<br />

1.00 qt<br />

Now multiply all numbers on the top and multiply all numbers on the bottom and write them as a<br />

fraction.<br />

2.6 qt 946 mL = 2,459.6 mL<br />

1.00 qt 1.00<br />

Now divide the top number by the bottom number and write that number with the unit that was not<br />

crossed out.<br />

26


1qt=32 oz 1gal = 4qts 1.00 qt = 946 mL 1L = 1000mL<br />

2. Convert 8135.6 mL to quarts<br />

8135.6 mL 1 qt<br />

=<br />

8135.6 qt<br />

8.6 qt<br />

8.6000 qt<br />

946 mL<br />

946<br />

3. Convert 115.2 oz to mL<br />

115.2 oz 1 qt 946 mL<br />

32 oz 1qt<br />

=<br />

108979.2 mL 3405.6 mL<br />

32 3406 mL<br />

4. Convert 2.3 g to Liters<br />

2.3 gal 4 qt<br />

1 gal<br />

946 mL<br />

1 qt<br />

1 L<br />

1000 mL<br />

=<br />

8703.2 L<br />

1000<br />

8.7032 L<br />

8.7 L<br />

5. Convert 8.42 L to oz<br />

8.42 L 1000 mL<br />

1 L<br />

1 qt<br />

946 mL<br />

32 oz<br />

1 qt<br />

=<br />

269440 oz<br />

946<br />

284.820296 oz<br />

285 oz<br />

Go to http://science.widener.edu/svb/tutorial/ chose #7 “Converting Volume” and do 5 more in the<br />

space provided.<br />

1. Convert _________ 4.1 qt to _________ mL<br />

4.1 qt 946 mL<br />

1 qt<br />

=<br />

3878 mL<br />

1<br />

3878 ml<br />

3900 ml<br />

2. Convert _________ 0.43 gal to _________<br />

L<br />

0.43 gal 4 qt<br />

946 mL<br />

1 gal<br />

1 qt<br />

1 L<br />

1000 mL<br />

=<br />

1627.12 L<br />

1000<br />

1.62712 L<br />

1.63 L<br />

3. Convert _________ 5.8 qt to _________<br />

mL<br />

5.8 qt 946 mL<br />

1 qt<br />

=<br />

5486.8 mL<br />

1<br />

5486.8 mL<br />

5400 mL<br />

4. Convert _________ 1.98 gal to _________ ml<br />

1.98 gal 4 qt<br />

946 mL<br />

=<br />

7492.32 mL<br />

7492.32 mL<br />

7490 mL<br />

1 gal<br />

1 qt<br />

1<br />

5. Convert _________ 208 Oz to _________ L<br />

208 oz 1 qt<br />

946 mL<br />

32 oz 1 qt<br />

1 L<br />

1000 mL<br />

=<br />

196768 L<br />

32000<br />

6.149 L<br />

6.15 L<br />

27


Chapter 4<br />

Unit 2<br />

Atomic Structure<br />

The students will learn what makes up atoms and how are<br />

atoms of one element different from atoms of another element.<br />

Explore the scientific theory of atoms (also known as atomic theory) by describing<br />

changes in the atomic model over time and why those changes were necessitated by<br />

experimental evidence.<br />

Students will be able to draw/identify each atomic model.<br />

Students will be able to compare/contrast the different atomic models.<br />

Students will be able to describe how results of experimental evidence caused the atomic<br />

model to change.<br />

proton<br />

nucleus<br />

electron<br />

electron cloud<br />

neutron<br />

Explore the scientific theory of atoms (also known as atomic theory) by describing the<br />

structure of atoms in terms of protons, neutrons and electrons, and differentiate among<br />

these particles in terms of their mass, electrical charges and locations within the atom.<br />

<br />

Students will compare/contrast the characteristics of subatomic particles.<br />

atomic number<br />

mass number<br />

isotope<br />

Chapter 5<br />

atomic mass unit (amu)<br />

atomic mass<br />

Electrons in Atoms<br />

The students will be able to describe the arrangement of<br />

electrons in atoms and predict what will happen when<br />

electrons in atoms absorb or release energy.<br />

Describe the quantization of energy at the atomic level.<br />

<br />

<br />

Students will participate in activities to view emission spectrums using a diffraction grating or a<br />

spectroscope.<br />

Students will be able to explain how the spectrum lines relate to electron motion.<br />

energy level<br />

atomic orbital<br />

quantum mechanical model<br />

28


Chapter 6<br />

The Periodic Table<br />

The student will learn what information the periodic table provides and<br />

how periodic trends can be explained.<br />

Relate properties of atoms and their position in the periodic table to the arrangement of<br />

their electrons.<br />

Students will be able to compare and contrast metals, nonmetals, and metalloids.<br />

Students will be able to describe the traits of various families on the periodic table.<br />

Students will be able to explain periodicity.<br />

Students will write/represent electron configuration of various elements.<br />

Students will be able to use a periodic table to calculate the number of p+, e-, and n0.<br />

Students will be able to calculate the average weight of mass<br />

periodic law<br />

halogen<br />

metals<br />

noble gas<br />

nonmetals<br />

transition metal<br />

metalloid<br />

atomic radius<br />

alkali metal<br />

ionization energy<br />

alkaline earth metal<br />

electronegativity<br />

Chapter 25 Nuclear <strong>Chemistry</strong><br />

The students will learn what happens when an unstable nucleus<br />

decays and how nuclear chemistry affects their lives.<br />

Explore the theory of electromagnetism by comparing and contrasting the different<br />

parts of the electromagnetic spectrum in terms of wavelength, frequency, and energy,<br />

and relate them to phenomena and applications.<br />

Students will be able to compare and contrast the different parts of the electromagnetic<br />

spectrum.<br />

Students will be able to apply knowledge of the EMS to real world phenomena.<br />

Students will be able to quantitatively compare the relationship between energy, wavelength,<br />

and frequency of the EMS.<br />

amplitude<br />

electromagnetic radiation<br />

wavelength<br />

photon<br />

frequency<br />

Planck’s constant<br />

hertz<br />

Explain and compare nuclear reactions (radioactive decay, fission and fusion), the<br />

energy changes associated with them and their associated safety issues.<br />

<br />

<br />

<br />

Students will be able to compare and contrast fission and fusion reactions.<br />

Students will be able to complete nuclear decay equations to identify the type of decay.<br />

Students will participate in activities to calculate half-life.<br />

Radioactivity<br />

nuclear radiation<br />

alpha particle<br />

beta particle<br />

gamma ray<br />

positron<br />

½ life<br />

transmutation<br />

fission<br />

fusion<br />

29


The Learning Goal for this assignment is:<br />

Explore the scientific theory of atoms ( also know as atomic theory) by describing changes in the atomic<br />

model over time and why those changes were necessitated by expiramental evidence.<br />

Notes Section<br />

Calculating atomic mass<br />

In order to calculate the atomic mass you must understand the occurences of number due to the percentage. The<br />

first step to understandin how to calculate atomic mas is turning your relative abudance/Amu into a decimal<br />

by makin it zero point and its original numbers. Then after you converted your amu into a decimal you times it by<br />

the mass. Then you repeat the same process with the other set of mass and amu. After you add both of the results<br />

up and then you get your awnser then you put in correct format by looking at the exact number of significant figures<br />

the first set of number had and you put the same amount of signifcant number in your final awnser.<br />

Ex<br />

The element is naturaly occurring isotopes with the masses numbers of 63 and 65. The realtive abudance and the<br />

atomis mass is 69.2 % for mass= 62.93 amu and 30.8% for mass= 64.93 amu. Calculate the atomic mass of<br />

Copper?<br />

First of you must get your first pair first which is :<br />

69.2% = 62.93 amu Repeat process with the other numbers.<br />

30.8=64.93<br />

Next you turn the amu into decimal.<br />

Turn amu into decimal<br />

0.6293 0.6493<br />

Then you multiply the decimal by the mass.<br />

Multiply decimal with mass<br />

69.2 x 0.6293 30.8 x 0.6493<br />

You recieve awnser<br />

you recieve youre awnser<br />

43.54756 19.99844<br />

Then you add both of your awnser together to get final awnser<br />

43.54756 + 19.99844 = 63.546<br />

you put in correct format by looking at the exact number of significant figures<br />

that the mass had and you put the same amount of signifcant number in your final awnser<br />

<strong>Final</strong> awnser : 63.5<br />

http://www.learner.org/interactives/periodic/basics_interactive.html<br />

30


Atoms Are Building Blocks<br />

Atoms are the basis of chemistry. They are the basis for everything in the Universe. You<br />

should start by remembering that matter is composed of atoms. Atoms and the study of<br />

atoms are a world unto themselves. We're going to cover basics like atomic structure<br />

and bonding between atoms.<br />

Smaller Than Atoms?<br />

Are there pieces of matter that are smaller than atoms?<br />

Sure there are. You'll soon be learning that atoms are<br />

composed of pieces like electrons, protons, and neutrons.<br />

But guess what? There are even smaller particles moving<br />

around in atoms. These super-small particles can be found<br />

inside the protons and neutrons. Scientists have many<br />

names for those pieces, but you may have heard of<br />

nucleons and quarks. Nuclear chemists and physicists<br />

work together at particle accelerators to discover the<br />

presence of these tiny, tiny, tiny pieces of matter.<br />

Even though super-tiny atomic particles exist, you only<br />

need to remember the three basic parts of an atom: electrons, protons, and neutrons.<br />

What are electrons, protons, and neutrons? A picture works best to show off the idea.<br />

You have a basic atom. There are three types of pieces in that atom: electrons, protons,<br />

and neutrons. That's all you have to remember. Three things! As you know, there are<br />

almost 120 known elements in the periodic table. Chemists and physicists haven't<br />

stopped there. They are trying to make new ones in labs every day. The thing that<br />

makes each of those elements different is the number of electrons, protons, and<br />

neutrons. The protons and neutrons are always in the center of the atom. Scientists call<br />

the center region of the atom the nucleus. The nucleus in<br />

a cell is a thing. The nucleus in an atom is a place where<br />

you find protons and neutrons. The electrons are always<br />

found whizzing around the center in areas called shells or<br />

orbitals.<br />

You can also see that each piece has either a "+", "-", or a<br />

"0." That symbol refers to the charge of the particle. Have<br />

you ever heard about getting a shock from a socket, static<br />

electricity, or lightning? Those are all different types of<br />

electric charges. Those charges are also found in tiny particles of matter. The electron<br />

always has a "-", or negative, charge. The proton always has a "+", or positive, charge. If<br />

the charge of an entire atom is "0", or neutral, there are equal numbers of positive and<br />

negative pieces. Neutral means there are equal numbers of electrons and protons. The<br />

third particle is the neutron. It has a neutral charge, also known as a charge of zero. All<br />

atoms have equal numbers of protons and electrons so that they are neutral. If there are<br />

more positive protons or negative electrons in an atom, you have a special atom called<br />

an ion.<br />

31


Looking at Ions<br />

We haven’t talked about ions before, so let’s get down to basics. The<br />

atomic number of an element, also called a proton number, tells you the<br />

number of protons or positive particles in an atom. A normal atom has a<br />

neutral charge with equal numbers of positive and negative particles.<br />

That means an atom with a neutral charge is one where the number of<br />

electrons is equal to the atomic number. Ions are atoms with extra<br />

electrons or missing electrons. When you are missing an electron or<br />

two, you have a positive charge. When you have an extra electron<br />

or two, you have a negative charge.<br />

What do you do if you are a sodium (Na) atom? You have eleven<br />

electrons — one too many to have an entire shell filled. You need to<br />

find another element that will take that electron away from you. When you lose that<br />

electron, you will you’ll have full shells. Whenever an atom has full shells, we say it is<br />

"happy." Let's look at chlorine (Cl). Chlorine has seventeen electrons and only needs<br />

one more to fill its third shell and be "happy." Chlorine will take your extra sodium<br />

electron and leave you with 10 electrons inside of two filled shells. You are now a happy<br />

atom too. You are also an ion and missing one electron. That missing electron gives you<br />

a positive charge. You are still the element sodium, but you are now a sodium ion (Na + ).<br />

You have one less electron than your atomic number.<br />

Ion Characteristics<br />

So now you've become a sodium ion. You have ten electrons.<br />

That's the same number of electrons as neon (Ne). But you<br />

aren't neon. Since you're missing an electron, you aren't really<br />

a complete sodium atom either. As an ion you are now<br />

something completely new. Your whole goal as an atom was<br />

to become a "happy atom" with completely filled electron<br />

shells. Now you have those filled shells. You have a lower<br />

energy. You lost an electron and you are "happy." So what<br />

makes you interesting to other atoms? Now that you have<br />

given up the electron, you are quite electrically attractive.<br />

Other electrically charged atoms (ions) of the opposite charge<br />

(negative) are now looking at you and seeing a good partner to<br />

bond with. That's where the chlorine comes in. It's not only chlorine. Almost any ion with<br />

a negative charge will be interested in bonding with you.<br />

32


Electrovalence<br />

Don't get worried about the big word. Electrovalence is just another word for something<br />

that has given up or taken electrons and become an ion. If you look at the periodic table,<br />

you might notice that elements on the left side usually become positively charged ions<br />

(cations) and elements on the right side get a negative charge (anions). That trend<br />

means that the left side has a positive valence and the right side has a negative<br />

valence. Valence is a measure of how much an atom wants to bond with other atoms. It<br />

is also a measure of how many electrons are excited about bonding with other atoms.<br />

There are two main types of bonding, covalent and electrovalent. You may have heard<br />

of the term "ionic bonds." Ionic bonds are electrovalent bonds. They are just groups of<br />

charged ions held together by electric forces. When in the presence of other ions, the<br />

electrovalent bonds are weaker because of outside electrical forces and attractions.<br />

Sodium and chlorine ions alone have a very strong bond, but as soon as you put those<br />

ions in a solution with H + (Hydrogen ion), OH - (Hydroxide), F - (Fluorine ion) or Mg ++<br />

(Magnesium ion), there are charged distractions that break the Na-Cl bond.<br />

Look at sodium chloride (NaCl) one more time. Salt is a very strong bond when it is<br />

sitting on your table. It would be nearly impossible to break those ionic/electrovalent<br />

bonds. However, if you put that salt into some water (H2O), the bonds break very<br />

quickly. It happens easily because of the electrical attraction of the water. Now you have<br />

sodium (Na + ) and chlorine (Cl - ) ions floating around the solution. You should remember<br />

that ionic bonds are normally strong, but they are very weak in water.<br />

33


Neutron Madness<br />

We have already learned that ions are atoms that are<br />

either missing or have extra electrons. Let's say an atom<br />

is missing a neutron or has an extra neutron. That type of<br />

atom is called an isotope. An atom is still the same<br />

element if it is missing an electron. The same goes for<br />

isotopes. They are still the same element. They are just a<br />

little different from every other atom of the same element.<br />

For example, there are a lot of carbon (C) atoms in the<br />

Universe. The normal ones are carbon-12. Those atoms have 6 neutrons. There are a<br />

few straggler atoms that don't have 6. Those odd ones may have 7 or even 8 neutrons.<br />

As you learn more about chemistry, you will probably hear about carbon-14. Carbon-14<br />

actually has 8 neutrons (2 extra). C-14 is considered an isotope of the element carbon.<br />

Messing with the Mass<br />

If you have looked at a periodic table, you may have noticed that the atomic mass of<br />

an element is rarely an even number. That happens because of the isotopes. If you are<br />

an atom with an extra electron, it's no big deal. Electrons don't have much of a mass<br />

when compared to a neutron or proton.<br />

Atomic masses are calculated by figuring out the<br />

amounts of each type of atom and isotope there are in<br />

the Universe. For carbon, there are a lot of C-12, a<br />

couple of C-13, and a few C-14 atoms. When you<br />

average out all of the masses, you get a number that is a<br />

little bit higher than 12 (the weight of a C-12 atom). The<br />

average atomic mass for the element is actually 12.011.<br />

Since you never really know which carbon atom you are<br />

using in calculations, you should use the average mass<br />

of an atom.<br />

Bromine (Br), at atomic number 35, has a greater variety of isotopes. The atomic mass<br />

of bromine (Br) is 79.90. There are two main isotopes at 79 and 81, which average out<br />

to the 79.90amu value. The 79 has 44 neutrons and the 81 has 46 neutrons. While it<br />

won't change the average atomic mass, scientists have made bromine isotopes with<br />

masses from 68 to 97. It's all about the number of neutrons. As you move to higher<br />

atomic numbers in the periodic table, you will probably find even more isotopes for<br />

each element.<br />

34


Summary<br />

Atoms are the most important part in chemistry and for evrthing in the universe. Matter is composed<br />

of by atoms which is anaything that takes up space. They consist of protons which are postively charged,<br />

and electrons which are negativitly charged and nuetrons which arent postive nor negative it is<br />

completely the opposite it has no charge. The nucleus in an atom is a place where the protons and neutrons<br />

are located at . The electrons are always found going around in a circle, in the center in areas named shells<br />

or orbitals. We have periodic table which consist of 120 elements which areall unique due to the fact that they<br />

each have diffrent number of electrons, proton and nuetrons. All atoms have equal amount of protons and<br />

electrons so that thier would be nuetral. An if thier is more postive protons or negative electrons then you have<br />

an ion.<br />

Normal atoms have a nuetral charge with an equal number of postive protons and negative electrons<br />

particles. This demonstrates tha an atoms with a nuetral charge in which the number of electrons and<br />

protons is equal to the atomic number. Ions are atom in which extra electrons or are missing electrons.<br />

When you are missing electrons the atom is goin to be postive and if thier is extra it is going to be<br />

negative. Ion are something completly diffrent from the rest and are completley new. Thier goal as an atom<br />

is to become a happy atom with completely filled electron layer . So if thier is to little in the outer most layer<br />

you get rid of them or if you near the octect rule you get the amount they need.<br />

You lose or gain an electron and they become happy atom. After the atom has given up the electron it is<br />

quite electrically attractive while on they other handelectrically charged atoms or postiveley charges if<br />

recieve.<br />

Electrovalence is just another name for something that has given up or taken electrons and has become<br />

an ion.The periodic table has elements on the left side which become positively charged ions which are<br />

called cations and elements on the right side are negatively charge which are called anions. That trend<br />

means that the left side of the periodic table has positive valence and the right side of the periodic table<br />

has negative valence. Valence is basically a measure of how much an atom wants to come togethere<br />

with other atoms.It is also a measure how many elctrons are happy to bond with other atoms.<br />

Their is two important parts of bonding covalent and electrovalent. Ionic bond are basically electrovalent<br />

bonds.There are just a group of charged ions that are held togethere by electric forces.<br />

When thier is more ions near the electrovalent bond it weakens the bond to due the reason that the<br />

outside force and is atracting. According to the text it states Salt is a very strong bond which is<br />

impossible to break the electrovalent bonds. If you put that salt into water the bonds<br />

diintegrates quickly. It happens easily because of the electrical attraction of the water. From this<br />

we can conclude that ionic bond are very strong but are very fragile and weak in water.<br />

When an atom is missing a neutron or has an extra neutron this specific type of atom is named an isotope.<br />

This atom is still the same element if it is missing an electron which also connects with istopes<br />

They will always be the exact same element. They are just sliglhtyly a bit different from every other atom<br />

of the same element<br />

35


Create groups for these Scientist and explain your groupings<br />

(use the information you got from your research)<br />

Group 1<br />

Atoine Henri Becquerel<br />

Democritus<br />

John Dalton<br />

Group 2<br />

Niels Bohr<br />

Louis de Barogilie<br />

Group 3<br />

Glen Seaborg<br />

Marie & Pierre Currie<br />

Dmitri Mendeleev<br />

Lother Meyer<br />

J W Dobereiner<br />

Group 4<br />

Eugene Goldstein<br />

JJ Thomson<br />

James Chadwick<br />

Erwin Shnodinger<br />

Robert Milikan<br />

Ernest Rutherford<br />

Hantaro Nagaoka<br />

1.<br />

I choose this grouping because its the begining of atomic theory. For example democritus was the one who started and<br />

he talks about how atoms make everthing and are indivisble . Then Atoine talks abou the basic rules matter cannot<br />

created nor destroyed and matter is made of atoms. Which also implies with atoms because nothing can change them either.<br />

Then john Dalton introduces atom. Overall I grouped thes scientis because they touch open atoms.<br />

2.<br />

I Choose this grouping because they both have something to dothe quatum theory . Niels bohr couldnt of created<br />

his model that showed electrons move around nuclues in specific energy levels the atom without the quantum theory.<br />

While on the other hand Louis de Barogilie he contributed largely to quantum theory and by saying electrons they act as waves.<br />

All in all they both touch open the quatum.<br />

3.<br />

I selected the third groupind due to the fact the touch open on the periodic table. For example Glen seaborg & Dmitri mendleeve<br />

dicovered new elements. As well Glen made groupings in the periodic table and J w dobereiner. As i stated before Dmitri<br />

he also created the priodic along with Lothar meyer. On the other hand Marie and Pierre Curie found out that elements emmit<br />

radiation without a source of energy. Basically they all have to do with the periodic table or the elemts within it.<br />

4<br />

I choose grouped these scientist in group because they all touch open the things of an atom. ( electrons, protons, nuetrons)<br />

Hantero nagaoke dicovered that thier was electrons ( negative) sorounding nuclues. On the other hand Eugene discovered<br />

important properties of the electrons. Both JJ thomson and Ernest rutherford touch opon the negative and postive charges<br />

of the atoms but ruther says that central has positive nucleus with negative electrons orbiting it whil ernst only discovered the<br />

postive/ negative. While james chadwick discovered the nuetron which are not postive nor negative. The last two focused on<br />

specific stuff Robert Milkar worked on how specify the size of the electron's charge and Erwin focused on using a mathmatics<br />

locating a precise spots where electrons were located around nuclues. To tie it all together they all touch on diffrent parts of the<br />

atom.<br />

36


Research the Scientist and summarize their contributions to the Atomic Theory<br />

You must have 2 to 3 complete sentences for each Scientist<br />

Antoine Henri Becquerel<br />

He determined the Law of conservation of matter through countless of expirements .<br />

The law states that matter cannot created nor destroyed.<br />

Niels Bohr<br />

He developed the orbit model of the atom based on the quantum theory. The model shows that electrons can only move<br />

around nucleus but in certain energy levels.<br />

Louis de Barogilie<br />

He contributed largely to quantum theory. He proposed that electrons behave as waves and that particles<br />

dont move in aregular orbit. It was called bregolis hypothesis.<br />

Glenn Seaborg<br />

He was involved in the synthesis disovery of the ten transuranuim elements (atomic number biger 92). which eventualy<br />

led him to development of the actonide conceptand the arangement of the metalic elements<br />

Hantaro Nagaoka<br />

He proposed an alternative planetary model of the atom. In which a postulate charged in the centerv sorounded by<br />

electrons. He also rejected JJ thomas model.<br />

Democritus<br />

He Proposed the idea of the atomic theory basically means he started atomic theory. It implies that everthing is made<br />

of atoms and which are physically indivisable.<br />

Marie and Pierre Curie<br />

They discovered radioctivity when they were expereminting with uranium. Then they found out that it emitted radiation<br />

without external source of energy.<br />

Eugene Goldstein<br />

He discovered several important properties which contributed to the electron. He noticed that particles were attracted to<br />

the electrons . It was protons later discoveres by his students.<br />

Dmitri Mendeleev<br />

He created the the periodic table arranged by elements according to thier atomic mass. Which eventually leaded him<br />

to discover more 8 more elements.<br />

J.J. Thomson<br />

Was the first person to suggest the theory of the atom containing positive and negative particles called electrons.<br />

He also showed the hydrogen atom has one electron. Dicovered first subamatic particle<br />

James Chadwick<br />

He discovered the Neutrons in atoms. He also located where they were ; in the center of an atom. They had neither a<br />

positive nor negative charge he said.<br />

Erwin Shrodinger<br />

He expanded upon the Bohr model of the atom. He used mathmatical procces to find th likely hood of where an<br />

electron was at.<br />

John Dalton<br />

He suggested the existence of the atom. It took almost alot before the atom was considered as a fundamental<br />

chemical object.<br />

Lothar Meyer<br />

He was one of the creators in developing the first periodic table of chemical elements. Both Mendeleev and<br />

Meyer worked togethere.<br />

Robert Millikan<br />

Millikan worked on an oil-drop experiment in which he measured the charge on a single electron.. Millikan's contribution<br />

to the hypothesis of thomas was to specify the size of the electron's charge<br />

J.W. Dobereiner<br />

Döbereiner said that thier trends in certain properties of selected groups of elements.<br />

Which he created Dobreiner traids.<br />

Ernest Rutherford<br />

Rutherford’s atomic theory was that an atom had a central positive nucleus with negative electrons orbiting it.<br />

He developed this theory with his gold foil experiment.<br />

37


38


39<br />

Electron Configuration<br />

Color the sublevel:<br />

s = Red<br />

d = Green<br />

p = Blue<br />

f = Orange<br />

Write in sublevels<br />

Write period, sublevel and super scripts.<br />

Ctrl Shift =<br />

gives you super scripts


The Learning Goal for this assignment is:<br />

Explore the scientific theory of atoms ( also know as atomic theory) by describing changes in the atomic model over time<br />

and why those changes were necessitated by expiramental evidence.<br />

40<br />

www.youtube.com/watch?v=jtYzEzykFdg<br />

www.youtube.com/watch?<br />

annotation_id=annotation_2076&feature=iv&src_vid=jtYzEzykFdg&v=cOlac8ruD_0<br />

www.youtube.com/watch?<br />

annotation_id=annotation_570977&feature=iv&src_vid=cOlac8ruD_0&v=lR2vqHZWb5A<br />

Notes Section<br />

Aufubaul= No^e<br />

N= Energy level<br />

0= orbital Type S P D F<br />

e= Number of electrons whithin orbital shell<br />

EX<br />

1s^1<br />

The one before the s is the number based on the row of the element is in. The s is which color of the sub level. While<br />

the 1 after is the number it is within the sublevel it is.<br />

Find AS^33<br />

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^3<br />

The reason why the 4s^2 is 3d is because of the formula d=n-1<br />

Or also in cases f=n-2<br />

The abriviated one is much easier but only do if asked to do it in that form.<br />

Always include the last completed noble gas .<br />

Volance electrons can form the octect rule electrons in the outermost energy level.<br />

Ex<br />

[Ar] 4s^2 3d^8<br />

The Ar stand for the last completed noble gas.<br />

4s^2 and 3d68 are the rest of the numbers afterthe last complted noble gas to get to the element you want you want to<br />

get to.<br />

Octet rule<br />

!st Energy level<br />

2nd Energy level<br />

3 Energy level<br />

4th Energy level<br />

We would always say that only eight will fit in the second and the outher energy levels only.But also 18 can fit in the sencond<br />

and the other outermost energy levels because the third row in the periodic table ends with 18 .<br />

Valance elctrons<br />

valance electrons have - or + only.<br />

Ex<br />

K= Potassium has one volance electron +1 because of the<br />

Sr= Stroonium has 2 valance elctrons +2 because of the colum<br />

Al= Has aluminum has three valance elctron because of the colum and also because the D is exclude.<br />

Cl= Chlorine is 1- because its going to get one electron since its just needs one more to get 8 . Since chlorine has 7 valance<br />

electrons it is inthe 17th group so you subtract 17- 10 because d is not considred. Then you get 7.


Electron Configuration<br />

In order to write the electron configuration for an atom you must know the 3 rules of<br />

electron configurations.<br />

1. Aufbau<br />

Notation<br />

nO e<br />

where<br />

n is the energy level<br />

O is the orbital type (s, p, d, or f)<br />

e is the number of electrons in that orbital shell<br />

Principle<br />

electrons will first occupy orbitals of the lowest energy level<br />

2. Hund rule<br />

when electrons occupy orbitals of equal energy, one electron enters each orbital until<br />

all the orbitals contain one electron with the same spin.<br />

3. Pauli exclusion principle<br />

an orbital contains a maximum of 2 electrons and<br />

paired electrons will have opposite spin<br />

41


In the space below, write the unabbreviated electron configurations of the following elements:<br />

1) sodium 1s^2 ________________________________________________<br />

2s^2 2p^6 3s^1<br />

2) iron 1s^2 ________________________________________________<br />

2s^2 2p^6 3s^2 3p^6 4s^2 3d^6<br />

3) bromine 1s^2 ________________________________________________<br />

2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^5<br />

4) barium ________________________________________________<br />

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2<br />

5) neptunium 1s^2 ________________________________________________<br />

2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 4f^14 5d^10 5p^4<br />

In the space below, write the abbreviated electron configurations of the following elements:<br />

6) cobalt ________________________________________________<br />

[Ar] 4s^2 3d^7<br />

7) silver ________________________________________________<br />

[Kr] 5s^2 4d^9<br />

8) tellurium ________________________________________________<br />

[Kr] 5s^2 4d^10 5p^4<br />

9) radium ________________________________________________<br />

[Rn] 7s^2<br />

10) lawrencium ________________________________________________<br />

[Rn] 7s^2 5f^14 6d^1<br />

Determine what elements are denoted by the following electron configurations:<br />

11) 1s²s²2p⁶3s²3p⁴ ____________________<br />

Sulfur<br />

12) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹ ____________________<br />

Rubidium<br />

13) [Kr] 5s²4d¹⁰5p³ ____________________<br />

Antimony<br />

14) [Xe] 6s²4f¹⁴5d⁶ ____________________<br />

Osmium<br />

15) [Rn] 7s²5f¹¹ ____________________<br />

Einsteinium<br />

Identify the element or determine that it is not a valid electron configuration:<br />

16) 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p⁵ ____________________<br />

Not valid its 3d^10 instead of 4d<br />

17) 1s²2s²2p⁶3s³3d⁵ ____________________<br />

Not valid Forgot about D<br />

18) [Ra] 7s²5f⁸ ____________________<br />

Not valid because Ra is not a noble gas<br />

19) [Kr] 5s²4d¹⁰5p⁵ ____________________<br />

Valid<br />

20) [Xe] ____________________<br />

No valid cannot be both<br />

1)sodium 1s 2 2s 2 2p 6 3s 1 2)iron 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6<br />

3)bromine 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 4)barium 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2<br />

5)neptunium 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 2 5f 5 6)cobalt [Ar] 4s 2 3d 7<br />

7)silver [Kr] 5s 2 4d 9 8)tellurium[Kr] 5s 2 4d 10 5p 4<br />

9)radium [Rn] 7s 2 10)lawrencium[Rn] 7s 2 5f 14 6d 1<br />

1s 2 2s 2 2p 6 3s 2 3p 4 sulfur 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 rubidium<br />

[Kr] 5s 2 4d 10 5p 3 antimony [Xe] 6s 2 4f 14 5d 6 osmium<br />

[Rn] 7s 2 5f 11 einsteinium 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 4d 10 4p 5 not valid (take a look at “4d”)<br />

1s 2 2s 2 2p 6 3s 3 3d 5 not valid (3p comes after 3s) [Ra] 7s 2 5f 8 not valid (radium isn’t a noble gas)<br />

[Kr] 5s 2 4d 10 5p 5 valid iodine<br />

20)[Xe] not valid (an element can’t be its own electron configuration)<br />

42


Ca= Calcium<br />

Ni=nickel<br />

C=carbon<br />

Xe=xenon<br />

S= sulfur<br />

U=uranium<br />

There is error in d because it can go to 4p due to<br />

the reason 3d is not completely filled.<br />

2<br />

1s<br />

1<br />

1s<br />

2<br />

2s<br />

1<br />

2p<br />

[Ne] 1<br />

3s<br />

[Ar] 2 2 2 2 2 2 2 2 2<br />

4s 3d10 4p<br />

[Ar] 2 - 1 - 1 - 1 - 1 - -<br />

4s 3d<br />

[Se] 2<br />

-<br />

1<br />

-<br />

1<br />

-<br />

1<br />

-<br />

3s 3p<br />

There is an error because the a box cannot have to error going to<br />

same position cause it throws it off balance.<br />

[He]<br />

-<br />

2 1<br />

-<br />

1<br />

2s 2p<br />

- -<br />

[Ar] 2<br />

-<br />

2<br />

-<br />

1<br />

-<br />

1<br />

-<br />

1<br />

- -<br />

1<br />

4s<br />

3d<br />

[xe] 2<br />

-<br />

2<br />

-<br />

2<br />

-<br />

2<br />

-<br />

2<br />

-<br />

2<br />

- -<br />

2<br />

-<br />

2 2<br />

-<br />

2<br />

-<br />

2<br />

-<br />

1<br />

-<br />

1<br />

6s 4f 5d<br />

-<br />

[Rn] 2<br />

-<br />

1<br />

-<br />

1<br />

-<br />

1<br />

-<br />

1<br />

-<br />

1<br />

-<br />

1<br />

- -<br />

7s<br />

[He] 2<br />

-<br />

2<br />

-<br />

1<br />

-<br />

1<br />

-<br />

2s 2p<br />

5f<br />

[Ar] 1 -4s<br />

43


Name ____________________<br />

Go to the web site www.darvill.clara.net/emag<br />

1. Click on “How the waves fit into the spectrum” and fill in this table:<br />

>: look out for the<br />

RED words on the web site!<br />

frequency<br />

Low __________, Long wavelength<br />

wave length<br />

High frequency, Short ______________<br />

Radio Waves<br />

micro waves infra red visible light ultra violet x-rays<br />

Gamma rays<br />

2. Click on “Radio waves”. They are used for _______________________<br />

communications<br />

3. Click on “Microwaves”. They are used for cooking, mobile _________, phones _______ wifi cameras and _________. radar<br />

4. Click on “Infra-red”. These waves are given off by _____ hot _________. objects They are used for remote controls,<br />

cameras in police ____________ helicopters , and alarm systems.<br />

5. Click on “Visible Light”. This is used in ___ dvd players and _______ laser printers, and for seeing where we’re going.<br />

6. “UV” stands for “ ultra ________ ___________”. violet This can damage the _________ retina in your eyes, and cause<br />

sunburn and even _______ skin cancer. Its uses include detecting forged ______ bank _______. notes<br />

7. X-rays are used to see inside people, and for _________ airport security.<br />

8. Gamma rays are given off by some ________________ radioactive substances. We can use them to kill ________ cancer cells,<br />

which is called R_______________ adiotherapy .<br />

9. My Quiz score is ____%. 100<br />

44


10. Name ________________________________<br />

Go to the web site www.darvill.clara.net/emag<br />

Name How they’re made Uses Dangers<br />

Gamma rays<br />

x-rays<br />

Ultra violet<br />

Visible light<br />

Infra red<br />

MIcro waves<br />

Radio waves<br />

They are created by the<br />

disenigration of radioactive<br />

subtances. When a nuclues decay<br />

into a more stable creates an<br />

excited state which is gamma rays .<br />

They are made by stars and<br />

some strong nebula .<br />

They are created by<br />

specila lamps.It is given off<br />

by the sun in large quantities<br />

They are made by anything<br />

thats hot enough to glow.<br />

Infra Red waves are made by<br />

stars, lamps, flames and and<br />

hot object.<br />

They are made made by<br />

various types of transmitter<br />

They are used to kill cancer cell. Also<br />

they are usedfor thing we need in<br />

everday life which is food. They<br />

sterlise ood so it can last longer as<br />

well as sterlise medicine<br />

They are use to see inside<br />

people. They are also used in<br />

airports for security use.<br />

Astronomers also use them.<br />

To see space objects<br />

They are used for various<br />

things such as sun tan,<br />

decting forged bank notes,<br />

kill microbes and produce vitamin D.<br />

They are use for allowing<br />

to see things. Disc which<br />

reflect light.<br />

They are used for remote<br />

controls for TVs , video recorders,<br />

and help heal sports injuries. Also<br />

see in the dark<br />

They are used in phones, wifi<br />

speed cameras and radars.<br />

They are made by transmitter, depending<br />

on the wavelength, and by stars, They are used for communications<br />

sparks and lightning.<br />

of diffrent frequencies.<br />

Some dangerous of gamma rays<br />

are causing cell damage<br />

which can lead to variety of<br />

cancers.They also cause mutation<br />

in growin tissue which unborns a<br />

re weak to.<br />

Some dangers of x-ray<br />

are that they can can<br />

cause cell damage and<br />

cancer ,<br />

Some dangerous are<br />

damage to eyes<br />

and sunburn even skin<br />

cancer<br />

The danger<br />

is causing damage<br />

to retina in your eye.<br />

The danger to people<br />

is overheating<br />

Long exporsure to<br />

microwaves cause<br />

caractar in eye<br />

They can cuase cancer<br />

if thier large dose.<br />

_____ Frequency _____ frequency,<br />

Short wavelength ______ Wavelength<br />

long<br />

high<br />

Low<br />

45


The Learning Goal for this Assignment is<br />

Restate properties of atoms and their postioms in the periodic table to the arragment of thier electrons.<br />

Alkali Metals<br />

They are a group in the periodic table consisting of the chemical elements lithium, sodium, pottasium, rubidium, caesium<br />

and francium. This group lies in th s-block of the periodoc table of elements as all alakli elements as they all have thier<br />

outermost electron in the s-orbital<br />

Alkali Earth Metals<br />

They are six chemical elements in group 2 of the periodic table. They all have similar properties such as<br />

bieng shiny, silvery white, somewhat reactive metals at standard temperature and presure.<br />

Beryllium, magnesium, calcium, stronium, barium, radium<br />

Transitional Metals<br />

Transitional metal elements are elements whose atoms has a partially filled d sub-shell or which can give rise to cations<br />

with an incomplete d sub-shell. They are from partial of group 3 through group 12.<br />

Inter Transitional Metals<br />

They are one of a group of chemical elements on the periodic table. They are normally shown in two rows below<br />

all the other elements on the periodic tablel They iclude elements 57 through 71 and 89 through 103.<br />

They have 3 complete outermost electron shells and are all metals. Sometimes are malleable and ductile.<br />

Metals<br />

I<br />

It is an element that is typically hard,shiny, and is a good at conducting electricity and thermal cundictivity. They are<br />

malleable they can be hammered without breaking and are as well fussible. 91 of the 118 elements are metals.<br />

Metalloids<br />

metalloid is any chemical element which has properties in between of metals and nonmetals or that has a<br />

mixture of them. Typical metalloids have a metallic appearance, but they are brittle and are okay conductors of<br />

electricity. They behave mostly as nonmetals<br />

Non Metals<br />

Thwy mostly lacks metallic. Nonmetals tend to be easily vaporized have low elasticity and are good insulators of heat<br />

and electricity. They have high ionization energy and electronegativity . Seventeen elements are non metals which are<br />

mostly gases.<br />

Noble Gases<br />

They make up a group of chemical elements with similar properties which are that they are all odorless, colorless,<br />

monatomic gases with very low chemical reactivity. The seven noble gases are helium, neon, argon,<br />

krypton , xenon, tradon. and Oganesson.<br />

46


Using Wikipedia, define the 8 categories of elements on the<br />

left page.<br />

Color your periodic table similar to the one on<br />

pages 168—169 of your book.<br />

alkali metals<br />

alkaline metals<br />

other metals<br />

transitional metals<br />

lanthanoids<br />

metalloids<br />

non metals<br />

halogens<br />

noble gases<br />

unknown elements<br />

actinoids<br />

47


Atomic Size<br />

Define Atomic Size:<br />

The atomic size is the distance from the nuclues to outermost energy layer. It the atomic<br />

radius . When comparing<br />

Explanation:<br />

The trend of the group is increading from the top to the bottom because the bottom has more energy levels.<br />

For example<br />

If the nuclues is bigger The nuclues is more charge the shorter. it is going to be<br />

If you have more protons its going to have a higher energy.<br />

Krypotn has biggers charge its going to pull in closer.<br />

This is counter intutive<br />

is the actual oposite is the bigger it is the smallet it actually is.<br />

48


Define Ionization Energy:<br />

Ionization Energy<br />

Ionization is the nergy neede to completley remobve an electron from the atom or ion. Ionaxition energy increase<br />

moving left to right accros the tabele and decreases moving down a group.<br />

Explanation:<br />

The larger the charge it is the easier to take the elctron away and it is closer to the left and going up it is easier to<br />

take it away.<br />

Weak magnet vs strong magnet.<br />

We look at two things<br />

Charge and energy level<br />

The closer to the nuclues the higher inozation.<br />

It easier to take an elctron from a small nuclues and greater distnace.<br />

49


Electronegativity<br />

Define Electronegativity:<br />

Electronegativity is teh measuremnet of how readily an atom forms a chemical bond. Electronegativity increase<br />

moving to the left to right across a period and decrease moving down a group.<br />

Explanation:<br />

Ectronegativity describes the frequency of an atom to attract<br />

electrons towards it. An atom's electronegativity is affected by<br />

atomic number and the distance at which its valence electrons are postion from the nuclues.<br />

IT is the amount of force it has to take it from another.<br />

Were going tohave to look at charge and energy levels<br />

YOu have to have enough energy level to take it away so it need to be closer.<br />

The charge has to take it away from the nuclues increases in charge so does the electro negativity.<br />

The arrow goes up because it is easier to take something away you have one energy level.<br />

50


51<br />

Define Ion Size:<br />

Ion Size<br />

Ion size is the measurement of the size of an atoms relataed ion. It is measured by from the<br />

center of the nuclues to the outermost used up electron cloud. It consist of cation and avions.<br />

Explanation:<br />

THey are all going to lose one due to the fact that the go down an energy level. Each have to have one less<br />

energy level which make the arrow go down and lose electrons. EVerthinh 14 and less are cat ion<br />

which measn the are postive because they gave up an electron .Evrthing over 14 isanvion an they are all negative<br />

because they are recieving . Non metalic gain electrons metalic lose elctrons.


Learning Goal for this section:<br />

Explain and compare nucluear reactions ( radioactive decay,fission and fusion), the energy changes associated with<br />

them and their asscociated safety issues.<br />

Notes Section:<br />

lpha looks like the nuclues of a heluim particle. Becaus they both have 2 protons and two nuetrons<br />

aughter is what we eject the aftter alpha particle. It pushes the nuclues 2 meters in air due to the<br />

eason it doesnt have Enough energy. It ejects because it is trying to become a stable atom,<br />

hanges becasue of the condition of the nuclues. We use the periodic table to determine the new<br />

thing which woulld have two less.Polumiom will give off two and become lead to beacome stable. It<br />

s not necasary to get stable only accurs sometimes.<br />

eta have the mass of electron it has very small amount of mass.It is negative. We wil take give<br />

wyay aelectrons so it becomes a proton . Its basically another way to make it nueatral. Cannot cau<br />

oves little further then beta.The betta goes up by 1.<br />

or example<br />

ranium becomes neptium becuse uranium adds one to become NP.<br />

roton give its postive charge to become nuertral. It makes it less table which makes it transform.<br />

Beta particles decay<br />

e+<br />

IN this situation the proton gives off it postive charge by going up one because the postive gives<br />

away to become nuetral.<br />

WHile E- it goes down 1<br />

Gamma radiation has to go through a transformation such as alpha particle decay or beta decay<br />

cause gamma radiation but slighty sometimes it does not<br />

Half life;<br />

After two days you would have half the mass due to the fact that it goes through a two day procce<br />

Mon=100g<br />

tues-less<br />

wen-less]'<br />

thur=25g<br />

sat-less<br />

sun-12.5.g<br />

52


The Nucleus<br />

A typical model of the atom is called the Bohr Model, in<br />

honor of Niels Bohr who proposed the structure in 1913. The Bohr atom consists of a central nucleus<br />

composed of neutrons and protons, which is surrounded by electrons which “orbit” around the nucleus.<br />

Protons carry a positive charge of one and have a mass of about 1 atomic mass unit or amu (1 amu =1.7x10-<br />

27 kg, a very, very small number). Neutrons are electrically “neutral” and also have a mass of about 1 amu. In<br />

contrast electron carry a negative charge and have mass of only 0.00055 amu. The number of protons in a<br />

nucleus determines the element of the atom. For example, the number of protons in uranium is 92 and the<br />

number in neon is 10. The proton number is often referred to as Z.<br />

Atoms with different numbers of protons are called elements, and are arranged in the periodic table with<br />

increasing Z.<br />

Atoms in nature are electrically neutral so the number of electrons orbiting the nucleus equals the number of<br />

protons in the nucleus.<br />

Neutrons make up the remaining mass of the nucleus and provide a means to “glue” the protons in place.<br />

Without neutrons, the nucleus would split apart because the positive protons would repel each other. Elements<br />

can have nucleii with different numbers of neutrons in them. For example hydrogen, which normally only has<br />

one proton in the nucleus, can have a neutron added to its nucleus to from deuterium, ir have two neutrons<br />

added to create tritium, which is radioactive. Atoms of the same element which vary in neutron number are<br />

called isotopes. Some elements have many stable isotopes (tin has 10) while others have only one or two. We<br />

express isotopes with the nomenclature Neon-20 or 20 Ne 10, with twenty representing the total number of<br />

neutrons and protons in the atom, often referred to as A, and 10 representing the number of protons (Z).<br />

Alpha Particle<br />

Decay<br />

Alpha decay is a radioactive process in which a<br />

particle with two neutrons and two protons is<br />

ejected from the nucleus of a radioactive atom. The particle is identical to the nucleus of a helium atom.<br />

Alpha decay only occurs in very heavy elements such as uranium, thorium and radium. The nuclei of these<br />

atoms are very “neutron rich” (i.e. have a lot more neutrons in their nucleus than they do protons) which makes<br />

emission of the alpha particle possible.<br />

After an atom ejects an alpha particle, a new parent atom is formed which has two less neutrons and two less<br />

protons. Thus, when uranium-238 (which has a Z of 92) decays by alpha emission, thorium-234 is created<br />

(which has a Z of 90).<br />

Because alpha particles contain two protons, they have a positive charge of two. Further, alpha particles are<br />

very heavy and very energetic compared to other common types of radiation. These characteristics allow alpha<br />

particles to interact readily with materials they encounter, including air, causing many ionizations in a very short<br />

distance. Typical alpha particles will travel no more than a few centimeters in air and are stopped by a sheet of<br />

paper.<br />

53


Beta Particle Decay<br />

Beta decay is a radioactive process in which an electron is emitted from the nucleus of a radioactive<br />

atom Because this electron is from the nucleus of the atom, it is called a beta particle to distinguish it<br />

from the electrons which orbit the atom.<br />

Like alpha decay, beta decay occurs in isotopes which are “neutron rich” (i.e. have a lot more<br />

neutrons in their nucleus than they do protons). Atoms which undergo beta decay are located below<br />

the line of stable elements on the chart of the nuclides, and are typically produced in nuclear reactors.<br />

When a nucleus ejects a beta particle, one of the neutrons in the nucleus is transformed into a proton.<br />

Since the number of protons in the nucleus has changed, a new daughter atom is formed which has<br />

one less neutron but one more proton than the parent. For example, when rhenium-187 decays<br />

(which has a Z of 75) by beta decay, osmium-187 is created (which has a Z of 76). Beta particles<br />

have a single negative charge and weigh only a small fraction of a neutron or proton. As a result, beta<br />

particles interact less readily with material than alpha particles. Depending on the beta particles<br />

energy (which depends on the radioactive atom), beta particles will travel up to several meters in air,<br />

and are stopped by thin layers of metal or plastic.<br />

Positron emission or beta plus decay (β+ decay) is a subtype of radioactive decay called beta decay,<br />

in which a proton inside a radionuclide nucleus is converted into a neutron while releasing a positron<br />

and an electron neutrino (νe). Positron emission is mediated by the weak force.<br />

An example of positron emission (β+ decay) is shown with magnesium-23 decaying into sodium-23:<br />

23 Mg12 → 23 Na11 + e +<br />

Because positron emission decreases proton number relative to neutron number, positron decay<br />

happens typically in large "proton-rich" radionuclides. Positron decay results in nuclear transmutation,<br />

changing an atom of one chemical element into an atom of an element with an atomic number that is<br />

less by one unit.<br />

Positron emission should not be confused with electron emission or beta minus decay (β− decay),<br />

which occurs when a neutron turns into a proton and the nucleus emits an electron and an<br />

antineutrino.<br />

54


Gamma<br />

Radiation<br />

After a decay reaction, the nucleus is often in an<br />

“excited” state. This means that the decay has<br />

resulted in producing a nucleus which still has<br />

excess energy to get rid of. Rather than emitting another beta or alpha particle, this energy is lost by<br />

emitting a pulse of electromagnetic radiation called a gamma ray. The gamma ray is identical in<br />

nature to light or microwaves, but of very high energy.<br />

Like all forms of electromagnetic radiation, the gamma ray has no mass and no charge. Gamma rays<br />

interact with material by colliding with the electrons in the shells of atoms. They lose their energy<br />

slowly in material, being able to travel significant distances before stopping. Depending on their initial<br />

energy, gamma rays can travel from 1 to hundreds of meters in air and can easily go right through<br />

people.<br />

It is important to note that most alpha and beta emitters also emit gamma rays as part of their decay<br />

process. However, their is no such thing as a “pure” gamma emitter. Important gamma emitters<br />

including technetium-99m which is used in nuclear medicine, and cesium-137 which is used for<br />

calibration of nuclear instruments.<br />

Half Life<br />

Half-life is the time required for the quantity of a<br />

radioactive material to be reduced to one-half its<br />

original value.<br />

All radionuclides have a particular half-life, some<br />

of which a very long, while other are extremely<br />

short. For example, uranium-238 has such a<br />

long half life, 4.5x109 years, that only a small fraction has decayed since the earth was formed. In<br />

contrast, carbon-11 has a half-life of only 20 minutes. Since this nuclide has medical applications, it<br />

has to be created where it is being used so that enough will be present to conduct medical studies.<br />

55


Inside the sun, fusion reactions take place at very high temperatures and enormous gravitational<br />

pressures.<br />

The foundation of nuclear energy is harnessing the power of atoms. Both fission and fusion are<br />

nuclear processes by which atoms are altered to create energy, but what is the difference between<br />

the two? Simply put, fission is the division of one atom into two, and fusion is the combination of two<br />

lighter atoms into a larger one. They are opposing processes, and therefore very different.<br />

Nuclear Fission<br />

The word fission means "a splitting or breaking<br />

up into parts". Nuclear fission releases heat<br />

energy by splitting atoms. The surprising<br />

discovery that it was possible to make a<br />

nucleus divide was based on Albert Einstein’s<br />

prediction that mass could be changed into<br />

energy using the Theory of Relativity<br />

E=MC 2 . In 1939, scientist began experiments,<br />

and one year later Enrico Fermi built the first<br />

nuclear reactor.<br />

Nuclear fission takes place when a large,<br />

somewhat unstable isotope (atoms with the<br />

same number of protons but different number<br />

of neutrons) is bombarded by high-speed<br />

particles, usually neutrons. These neutrons<br />

are accelerated and then slammed into the<br />

unstable isotope, causing it to fission, or break<br />

into smaller particles. During the process, a<br />

neutron is accelerated and strikes the target<br />

nucleus, which in the majority of nuclear<br />

power reactors today is Uranium-235. This<br />

splits the target nucleus and breaks it down<br />

into two smaller isotopes (the fission<br />

products), three high-speed neutrons, and a<br />

large amount of energy.<br />

This resulting energy is then used to heat<br />

water in nuclear reactors and ultimately<br />

produces electricity. The high-speed<br />

neutrons that are ejected become projectiles<br />

that initiate other fission reactions, or chain<br />

reactions.<br />

https://www.youtube.com/watch?v=0v8i4v1mieU<br />

https://www.youtube.com/watch?v=1U6Nzcv9Vws<br />

https://www.youtube.com/watch?v=MGj_aJz7cTs<br />

56


Nuclear Fission<br />

The word fusion means "a merging of separate elements into a unified whole". Nuclear fusion refers<br />

to the "union of atomic nuclei to form heavier nuclei resulting in the release of enormous amounts of<br />

energy". Fusion takes place when two low-mass isotopes, typically isotopes of hydrogen, unite under<br />

conditions of extreme pressure and temperature.<br />

Fusion is what powers the sun. Atoms of Tritium and Deuterium (isotopes of hydrogen, Hydrogen-3<br />

and Hydrogen-2, respectively) unite under extreme pressure and temperature to produce a neutron<br />

and a helium isotope. Along with this, an enormous amount of energy is released, which is several<br />

times the amount produced from fission.<br />

Scientists continue to work on controlling nuclear fusion in an effort to make a fusion reactor to<br />

produce electricity. Some scientists believe there are opportunities with such a power source since<br />

fusion creates less radioactive material than fission and has a nearly unlimited fuel supply. However,<br />

progress is slow due to challenges with understanding how to control the reaction in a contained<br />

space.<br />

Both fission and fusion are nuclear reactions that<br />

produce energy, but the applications are not the<br />

same. Fission is the splitting of a heavy, unstable<br />

nucleus into two lighter nuclei, and fusion is the<br />

process where two light nuclei combine together<br />

releasing vast amounts of energy. Fission is used in<br />

nuclear power reactors since it can be controlled,<br />

while fusion is not utilized to produce power since<br />

the reaction is not easily controlled and is<br />

expensive to create the needed conditions for a<br />

fusion reaction. Research continues into ways to<br />

better harness the power of fusion, but research is<br />

in experimental stages. While different, the two<br />

processes have an important role in the past,<br />

present and future of energy creation.<br />

Summary Section<br />

Proton sare postivley charged of only one about 1 atomic mass unit/ Amu.Nuetrons have no charge and have a mass of 1<br />

amu . Elctrons carry one negative charge and have a mass of 0.00055 amu. Atoms in nature are nuetral so that the number<br />

of elctrons orbiting the nuclues equals the number of proton in the nuclues which make it stable but if thier not stable they are<br />

called ions. Alpha decay is a radioactive process in which a particle with two nuetron and two protons is forced out from the<br />

the nuclues of a radioactive atom. Aplha decay only accur in heavy elements. While on the other hand Beta deacy is a<br />

rafioactive procces in which electrons is taking in from the nuclues of radioactive atom. But both Alpha decay and Beta decay<br />

accur in istopes which means that they are very nuetron rich. After an decay their is various thing that acuur such as<br />

the nuclues bieng in very excited mode. This means that the decay has a result in which produces a nuclues which still has<br />

huge amount of energy to get rid of . Gammy ray is like nature to light or microwaves but huge amount of higer energy.<br />

Gamma rays is very diffrent from all electromagnectic radiation duee to the reason that gamma rays has no mass and<br />

no charge. Half life is the time in which time is required for the quantity of radioactive material to be reduced to one half of its<br />

origanl value. Fusion reaction take place in very high temperatures and gravitational forces. Fission means the splitting or<br />

breaking of parts.Nuclear fission releases heat by the slpiting of atoms. Both fisions and fussion are nuclear procces in<br />

which atoma re bieng modified to create energy . They are difrent due to the fact the appliaction are not the same.<br />

57


Chapter 7<br />

Unit 3<br />

Ionic and Metallic Bonding<br />

The students will learn how ionic compounds form and how<br />

metallic bounding affects the properties of metals.<br />

Compare the magnitude and range of the four fundamental forces<br />

(gravitational, electromagnetic, weak nuclear, strong nuclear).<br />

Students will compare/contrast the characteristics of each fundamental force.<br />

gravity<br />

electromagnetic<br />

strong<br />

weak<br />

Distinguish between bonding forces holding compounds together and other<br />

attractive forces, including hydrogen bonding and van der Waals forces.<br />

Students will be able to compare/contrast traits of ionic and covalent bonds.<br />

Students will be able to compare/contrast basic attractive forces between<br />

molecules.<br />

<br />

Students will be able to predict the type of bond or attractive force between<br />

atoms or molecules.<br />

ionic bond<br />

covalent bond<br />

metallic bond<br />

polar covalent bond<br />

hydrogen bond<br />

van der Waals forces<br />

London dispersion forces<br />

Chapter 8<br />

Covalent Bonding<br />

The students will learn how molecular bonding is different<br />

than ionic bonding and electrons affect the shape of a<br />

molecule and its properties.<br />

Interpret formula representations of molecules and compounds in terms of<br />

composition and structure.<br />

Students will be able to interpret chemical formulas in terms of # of atoms.<br />

Students will be able to differentiate between ionic and molecular compounds.<br />

Students will be able to list various VSEPR shapes and identify examples of<br />

each.<br />

58


Students will be able to predict shapes of various compounds.<br />

Atom<br />

Electron<br />

Element<br />

Compound<br />

Molecule<br />

empirical formula<br />

Chapter 9<br />

Chemical Names and Formulas<br />

The students will learn how the periodic table helps them<br />

determine the names and formulas of ions and compounds.<br />

59


The Learning Goal for this assignment is:<br />

Distinguish between bonding forces holding compounds together and other attractive forces, including hydrogen<br />

bonding and van der Waals forces.<br />

Introduction to Ionic Compounds<br />

Those molecules that consist of charged ions with opposite charges are called IONIC. These ionic<br />

compounds are generally solids with high melting points and conduct electrical current. Ionic<br />

compounds are generally formed from metal and a non-metal elements. See Ionic Bonding below.<br />

Ionic Compound Example<br />

For example, you are familiar with the fairly benign unspectacular behavior of common white<br />

crystalline table salt (NaCl). Salt consists of positive sodium ions (Na + ) & negative chloride ions (Cl - ).<br />

On the other hand the element sodium is a silvery gray metal composed of neutral atoms which react<br />

vigorously with water or air. Chlorine as an element is a neutral greenish-yellow, poisonous, diatomic<br />

gas (Cl2).<br />

The main principle to remember is that ions are completely different in physical and chemical<br />

properties from the neutral atoms of the elements.<br />

The notation of the + and - charges on ions is very important as it conveys a definite meaning.<br />

Whereas elements are neutral in charge, IONS have either a positive or negative charge depending<br />

upon whether there is an excess of protons (positive ion) or excess of electrons (negative ion).<br />

Formation of Positive Ions<br />

Metals usually have 1-4 electrons in the outer energy level. The electron arrangement of a rare gas is<br />

most easily achieved by losing the few electrons in the newly started energy level. The number of<br />

electrons lost must bring the electron number "down to" that of a prior rare gas. How will sodium<br />

complete its octet?<br />

First examine the electron arrangement of the atom. The atomic number is eleven, therefore, there<br />

are eleven electrons and eleven protons on the neutral sodium atom. Here is the Bohr diagram and<br />

Lewis symbol for sodium:<br />

This analysis shows that sodium has only one electron in its outer level. The nearest rare gas is neon<br />

with 8 electron in the outer energy level. Therefore, this electron is lost so that there are now eight<br />

60


electrons in the outer energy level, and the Bohr diagrams and Lewis symbols for sodium ion and<br />

neon are identical. The octet rule is satisfied.<br />

Ion Charge?<br />

What is the charge on sodium ion as a result of losing one electron? A comparison of the atom and<br />

the ion will yield this answer.<br />

Sodium Atom<br />

Sodium Ion<br />

11 p+ to revert to 11 p + Protons are identical in<br />

12 n<br />

11 e-<br />

0 charge<br />

an octet lose 1<br />

electron<br />

12 n<br />

10 e-<br />

+ 1 charge<br />

the atom and ion.<br />

Positive charge is<br />

caused by lack of<br />

electrons.<br />

Formation of Negative Ions<br />

How will fluorine complete its octet?<br />

First examine the electron arrangement of the atom. The atomic number is nine, therefore, there are<br />

nine electrons and nine protons on the neutral fluorine atom. Here is the Bohr diagram and Lewis<br />

symbol for fluorine:<br />

This analysis shows that fluorine already has seven electrons in its outer level. The nearest rare gas<br />

is neon with 8 electron in the outer energy level. Therefore only one additional electron is needed to<br />

complete the octet in the fluorine atom to make the fluoride ion. If the one electron is added, the Bohr<br />

diagrams and Lewis symbols for fluorine and neon are identical. The octet rule is satisfied.<br />

Ion Charge?<br />

What is the charge on fluorine as a result of adding one electron? A comparison of the atom and the<br />

ion will yield this answer.<br />

Fluorine Atom Fluoride Ion *<br />

61


9 p+ to complete 9 p + Protons are identical in 10 n octet add 1 10 n the<br />

atom and ion.<br />

9 e- electron 10 e- Negative charge is<br />

10 charge - 1 charge<br />

caused by excess<br />

electrons *<br />

The "ide" ending in the name signifies a simple negative ion.<br />

Summary Principle of Ionic Compounds<br />

An ionic compound is formed by the complete transfer of electrons from a metal to a nonmetal and<br />

the resulting ions have achieved an octet. The protons do not change. Metal atoms in Groups 1-3<br />

lose electrons to non-metal atoms with 5-7 electrons missing in the outer level. Non-metals gain 1-4<br />

electrons to complete an octet.<br />

Octet Rule<br />

Elemental atoms generally lose, gain, or share electrons with other atoms in order to achieve the<br />

same electron structure as the nearest rare gas with eight electrons in the outer level.<br />

The proper application of the Octet Rule provides valuable assistance in predicting and explaining<br />

various aspects of chemical formulas.<br />

Introduction to Ionic Bonding<br />

Ionic bonding is best treated using a simple electrostatic model. The electrostatic model is simply an<br />

application of the charge principles that opposite<br />

charges attract and similar charges repel. An ionic<br />

compound results from the interaction of a positive<br />

and negative ion, such as sodium and chloride in<br />

common salt.<br />

Energy + Metal Atom ---> Metal (+) ion + e-<br />

The IONIC BOND results as a balance between<br />

the force of attraction between opposite plus and<br />

minus charges of the ions and the force of<br />

repulsion between similar negative charges in the<br />

electron clouds. In crystalline compounds this net<br />

balance of forces is called the LATTICE ENERGY.<br />

Lattice energy is the energy released in the<br />

formation of an ionic compound.<br />

DEFINITION: The formation of an IONIC BOND is<br />

the result of the transfer of one or more electrons<br />

from a metal onto a nonmetal.<br />

Metals, with only a few electrons in the outer<br />

energy level, tend to lose electrons most readily.<br />

The energy required to remove an electron from a<br />

neutral atom is called the IONIZATION<br />

POTENTIAL.<br />

62


Non-metals, which lack only one or two electrons in the outer energy level have little tendency to<br />

lose electrons - the ionization potential would be very high. Instead non-metals have a tendency to<br />

gain electrons. The ELECTRON AFFINITY is the energy given off by an atom when it gains<br />

electrons.<br />

Non-metal Atom + e- --- Non-metal (-) ion + energy<br />

The energy required to produce positive ions (ionization potential) is roughly balanced by the energy<br />

given off to produce negative ions (electron affinity). The energy released by the net force of<br />

attraction by the ions provides the overall stabilizing energy of the compound.<br />

https://www.youtube.com/watch?v=zpaHPXVR8W U<br />

Writing Ionic Compounds<br />

An easy technique for creating a neutral combination of two charged ions is called the criss-cross<br />

technique. When writing a formula for an ionic compound the charges from each ion are simply<br />

switched to become the subscript values written to designate the number of atoms present in a<br />

compound. See the example below.<br />

Naming Ionic Compounds<br />

Naming Binary Ionic Compounds<br />

Learning to name ionic compounds is both easy and hard depending on the complexity of the<br />

compound. Before we start, though, I just wanted to review a few terms. Remember that positively<br />

charged ions are called cations. Negatively charged ions are called anions. An ionic compound is a<br />

compound held together by ionic bonds. A simple binary compound is just what it seems - a simple<br />

compound with two elements in it.<br />

Binary compounds are easy to name. The cation is always named first and gets its name from the<br />

name of the element. For example, K + is called a potassium ion. An anion also takes its name from<br />

its element, but it adds the suffix -ide to it. So, Cl - is called a chloride ion; O 2- is an oxide ion.<br />

Take the binary compound NaCl. The Na + is a sodium cation. The Cl - is a chlorine anion, which<br />

gets the suffix -ide added to it. When you put them together, it becomes sodium chloride. Here are<br />

some examples for you:<br />

Zn 2+ is zinc. S 2- is sulfide. Put them together for zinc sulfide (ZnS).<br />

63


Here's another:<br />

K2O is potassium oxide<br />

Naming Ionic Compounds Containing Transition Metals<br />

A transition metal is a metal that can use the inner shell before using the outer shell to bond. These<br />

are the elements in the middle of the periodic table - things like zinc, iron and copper. Naming<br />

polyatomic ionic compounds that have transition metals in them is also fairly easy. It follows the<br />

same naming rules as the simple binary compounds, but with an extra rule added in. So, you still<br />

name the cation first, followed by the anion with the suffix -ide added to the end of it.<br />

The new rule is that transition metals form more than one ion, so this has to be accounted for in the<br />

naming. We do this by using Roman numerals to denote which ion it is. The Roman numeral will<br />

equal the charge on the ion. For instance, Fe 2+ is iron (II). Fe 3+ is iron (III).<br />

When compounds are formed with these metals, the different ions still have to be accounted for. If I<br />

told you the compound was iron chloride, that wouldn't give you the full story. You wouldn't know if it<br />

was iron (II) or iron (III), which means you don't know how many chlorine atoms are in the compound<br />

to bond with the iron, since two chlorines would be needed for iron (II) and three for iron (III). If I<br />

instead told you that the compound was iron (II) chloride, you would know that it was Fe 2+ in there,<br />

which means you have two chlorine atoms bonding with it. The formula would be FeCl2. If I said it<br />

was iron (III) chloride, the formula would be FeCl3.<br />

Naming Polyatomic Ionic Compounds<br />

A polyatomic ionic compound is a compound made up of a polyatomic ion, which is two or more<br />

atoms bonded together, and a metal. Naming polyatomic ions is harder, but doable. First, name the<br />

cation, which is just the name of the element. Next, name the anion. This gets trickier.<br />

Notes Section:<br />

AB+ CD<br />

AD + CB<br />

The AB will always have to be a Cation while on the other hand the Cd will always be an anion.<br />

This is like the equation which will help you name the compound name. By following the step of fist<br />

adding your two things together. Furthermore, then you swap the order by putting the A with d and<br />

Putting c with B. Then you must remember that there sub level switches to the other Element<br />

Example; Fe2C3<br />

Your answer would be actually in reverse due to the reasoning that its supposed to be flipped.<br />

So, the answer would be: Fe3C2<br />

Finding name of compound Example; Aluminum Iodine d+ Mercury (ii) chloride<br />

You first look at the valence electrons and ho much it would need to become neutral unless they<br />

provide you with a roman numeral you must use that as the sub number.<br />

Al 3 + I 1- 1. add 3+ in order make it stable. Hg 2+ Cl 1. Add 2 to power because it says<br />

ALI3 2. We flip the sub levels so it opposite HgCl2 2, we repeat the same steps the last<br />

Lastly, we Turn the Ab+C formula to AD CB to get final result<br />

64


AlCl3+ HgI2 But remember to look back at the d=first step so you don’t flip it the wrong way :<br />

1<br />

2<br />

3<br />

Name of<br />

Cation<br />

Calcium ion<br />

Iron(III) ion<br />

Name of<br />

Anion<br />

Chloride ion<br />

Phosphide<br />

ion<br />

Formula<br />

of Cation<br />

Ca2+<br />

Fe3+ P3-<br />

Formula of<br />

Anion<br />

Formula of<br />

Compound<br />

Name of Compound<br />

Cl - CaCl2 Calcium Chloride<br />

Fep<br />

Sodium ion Sulfide ion Na1+ S2- Na2s<br />

Iron(III) Phosphide<br />

Sodium sulfide<br />

4<br />

5<br />

Aluminum ion Bromide Al 3+ Br1- AlBr3<br />

Aluminum Bromide<br />

Lithium Ion Sulfide ion<br />

LI1+<br />

S2- Li2s Lithium Sulfide<br />

6 Platinum (IV)<br />

ion<br />

7 Magnesium<br />

ion<br />

8<br />

Calcium ion<br />

9 Mercury (II)<br />

ion<br />

Oxide ion<br />

Carbonate<br />

ion<br />

Nitrate<br />

Pt4+<br />

Mg2+<br />

O-2<br />

CO32-<br />

Pt2o4<br />

MgCo3<br />

Ca 2+ NO31- Ca(No3)2<br />

Sulfide ion Hg2+ S2-<br />

10 Thorium (II) Phosphate TH2+<br />

Write the formulas for these ionic compounds<br />

11. Chromium (IV) oxide Cr 4+ O -2 cr 2O 4<br />

Po43-<br />

HgS<br />

Th3(PO4)2<br />

Platinum (IV) Oxide<br />

Magnesium<br />

Carbonate<br />

Calcium Nitrate<br />

Mercury(II) Sulfide<br />

Thorium(II)<br />

Phosphate<br />

12. Chromium (III) oxide cr 5+ O -2 Cr2O3<br />

13. Aluminum oxide Al 5+ 0 -2 Al2O3<br />

14. Nickel (II) bromide Ni 2+ Br 1- NiBr2<br />

15. Silver (I) sulfide Ag+1 S2- Ag2s2<br />

16. Magnesium chloride Mg 2+ Cl - MgCl2<br />

17. Nickel (II) sulfate Ni 2+ SO 4<br />

2- NiSo4<br />

18. Iron (III) phosphate Fe 3+ Po4 3- FePo<br />

19. Potassium dichromate k + CrO 4<br />

20. Lead (IV) hydroxide Pb 4+ Ho<br />

PbHO<br />

K2(CrO4<br />

65


The Learning Goal for this assignment is:<br />

Interpret formula representations of molecules and compounds in terms of composition and structure.<br />

Introduction to Covalent Bonding:<br />

Bonding between non-metals consists of two electrons shared between two atoms. Using the Wave<br />

Theory, the covalent bond involves an overlap of the electron clouds from each atom. The electrons<br />

are concentrated in the region between the two atoms. In covalent bonding, the two electrons shared<br />

by the atoms are attracted to the nucleus of both atoms. Neither atom completely loses or gains<br />

electrons as in ionic bonding.<br />

There are two types of covalent bonding:<br />

1. Non-polar bonding with an equal sharing of electrons.<br />

2. Polar bonding with an unequal sharing of electrons. The number of shared electrons depends on<br />

the number of electrons needed to complete the octet.<br />

NON-POLAR BONDING results when two identical non-metals equally share electrons between<br />

them. One well known exception to the identical atom rule is the combination of carbon and hydrogen<br />

in all organic compounds.<br />

Hydrogen<br />

The simplest non-polar covalent molecule is hydrogen. Each hydrogen<br />

atom has one electron and needs two to complete its first energy level.<br />

Since both hydrogen atoms are identical, neither atom will be able to<br />

dominate in the control of the electrons. The electrons are therefore<br />

shared equally. The hydrogen covalent bond can be represented in a<br />

variety of ways as shown here:<br />

The "octet" for hydrogen is only 2 electrons since the nearest rare gas is<br />

He. The diatomic molecule is formed because individual hydrogen atoms<br />

containing only a single electron are unstable. Since both atoms are<br />

identical a complete transfer of electrons as in ionic bonding is<br />

impossible.<br />

Instead the two hydrogen atoms SHARE both electrons equally.<br />

Oxygen<br />

Molecules of oxygen, present in about 20% concentration in air are<br />

also covalent molecules. See the graphic on the left of the Lewis Dot<br />

Structure.<br />

There are 6 electrons in the outer shell, therefore, 2 electrons are<br />

needed to complete the octet. The two oxygen atoms share a total of<br />

four electrons in two separate bonds, called double bonds.<br />

The two oxygen atoms equally share the four electrons.<br />

66


POLAR BONDING results when two different non-metals unequally share electrons between them.<br />

One well known exception to the identical atom rule is the combination of carbon and hydrogen in all<br />

organic compounds.<br />

The non-metal closer to fluorine in the Periodic Table has a greater tendency to keep its own electron<br />

and also draw away the other atom's electron. It is NOT completely successful. As a result, only<br />

partial charges are established. One atom becomes partially positive since it has lost control of its<br />

electron some of the time. The other atom becomes partially negative since it gains electron some of<br />

the time.<br />

Hydrogen Chloride<br />

Hydrogen Chloride forms a polar covalent molecule. The graphic<br />

on the left shows that chlorine has 7 electrons in the outer shell.<br />

Hydrogen has one electron in its outer energy shell. Since 8<br />

electrons are needed for an octet, they share the electrons.<br />

However, chlorine gets an unequal share of the two electrons,<br />

although the electrons are still shared (not transferred as in ionic<br />

bonding), the sharing is unequal. The electrons spends more of the<br />

time closer to chlorine. As a result, the chlorine acquires a "partial"<br />

negative charge. At the same time, since hydrogen loses the<br />

electron most - but not all of the time, it acquires a "partial" charge.<br />

The partial charge is denoted with a small Greek symbol for delta.<br />

Water<br />

Water, the most universal compound on all of the earth, has the property of<br />

being a polar molecule. As a result of this property, the physical and<br />

chemical properties of the compound are fairly unique.<br />

Dihydrogen Oxide or water forms a polar covalent molecule. The graphic on<br />

the left shows that oxygen has 6 electrons in the outer shell. Hydrogen has<br />

one electron in its outer energy shell. Since 8 electrons are needed for an<br />

octet, they share the electrons.<br />

Notes Section:<br />

There are two types of covalent bonding which are polar bonding and non polar. Non-polar bondingis when thiers is<br />

an equal sharing of electron. polarbonding and unequal sharing electrons and number of shared electrons matter<br />

on theoctect rule to become stable. non polar is when two same not metals share elctrons. Their only one thing from this<br />

which is hydrogen.<br />

In order to make the covalent bond is go through the 8 step procces which is First of is you need to find the valence electron<br />

for all atoms. Add them together. Next we need to find octet for each atom and add them together. Furthermore (3) we<br />

need to Subtract Step 1 from Step 2. Find number of bonds by diving the number by 2 which gives us the bond.<br />

Additionaly we find out which is least electronegative is. Then we put the atoms in the structure that bond them together.<br />

Use the periodic table and find the one farthest away from Fluorine .Then we subtratct step 1from 3 and divide by 2 to get<br />

number of Lone pair. <strong>Final</strong>ly we find formal charges for the atoms. Arrange atoms so that all formal charges are 0 ot<br />

Ex: H20t<br />

Metal: non metal 1 1 to 1 ratio. When two metals come togethere they disacioate . Spread all over the place,<br />

1. H2*1=2 In this step we look at the group . For exampl hydrogen is 1 and oxegen is in group 6.<br />

O1*6 =6<br />

8e-<br />

2. H2*2=4 In the second step we Multiply all things by eight to satisfy the octet rule of eight. The inly execption<br />

O1*8=8 Hydrogen which you multiply by .<br />

12e-<br />

3 12-6= 6e All you do in this tep is subtract step 2 by step 1.<br />

4 6/2 -= 3bonds All we do in this step as you can clearly can see is divide eby 2 to get the number of bond we need.<br />

5And 6<br />

We ajusted this to a structure in which makes sense<br />

H O H<br />

7&8 8-6=2 lp We plug 2 lone pair on top<br />

Prefix number<br />

Mono 1<br />

Di 2<br />

tri 3<br />

tetra 4<br />

pentra 5<br />

hexa 6<br />

hepta 7<br />

octa 8<br />

nona 9<br />

deca 10 67


C 2 H 6 O Ethanol CH 3 CH 2 O<br />

Step 1<br />

Find valence e- for all atoms. Add them together.<br />

C: 4 x 2 = 8<br />

H: 1 x 6 = 6<br />

O: 6<br />

Total = 20<br />

Step 2<br />

Find octet e- for each atom and add them together.<br />

C: 8 x 2 = 16<br />

H: 2 x 6 = 12<br />

O: 8<br />

Total = 36<br />

Step 3<br />

Subtract Step 1 total from Step 2.<br />

Gives you bonding e-.<br />

36 – 20 = 16e-<br />

Step 4<br />

Find number of bonds by diving the number in step 3 by 2<br />

(because each bond is made of 2 e-)<br />

16e- / 2 = 8 bond pairs<br />

These can be single, double or triple bonds.<br />

Step 5<br />

Determine which is the central atom<br />

Find the one that is the least electronegative.<br />

Use the periodic table and find the one farthest<br />

away from Fluorine or<br />

The one that only has 1 atom.<br />

68


Step 6<br />

Put the atoms in the structure that you think it will<br />

have and bond them together.<br />

Put Single bonds between atoms.<br />

Step 7<br />

Find the number of nonbonding (lone pairs) e-.<br />

Subtract step 3 number from step 1.<br />

20 – 16 = 4e- = 2 lone pairs<br />

Step 8<br />

Complete the Octet Rule by adding the lone<br />

pairs.<br />

Add any left over bonds to make double or triple<br />

bonds.<br />

Then, if needed, use any lone pairs to make<br />

double or triple bonds so that all atoms meet<br />

the Octet Rule.<br />

See Step 4 for total number of bonds.<br />

Step 9<br />

Find the formal charges for the atoms in the compound.<br />

Arrange atoms so that all formal charges<br />

are as close to 0 as possible.<br />

Some central atoms do not meet the octet rule.<br />

Boron can sometimes have only 6 electrons and<br />

some elements in Periods 3—7 may exceed the<br />

octet rule.<br />

69


Name Formula Charge<br />

Dichromate Cr₂O₇ 2-<br />

Sulfate SO₄ 2-<br />

Hydrogen Carbonate HCO₃ 1-<br />

Hypochlorite ClO 1-<br />

Phosphate PO₄ 3-<br />

Nitrite NO₂ 1-<br />

Chlorite ClO₂ 1-<br />

Dihydrogen phosphate H₂PO₄ 1-<br />

Chromate CrO₄ 2-<br />

Carbonate CO₃ 2-<br />

Hydroxide OH 1-<br />

Hydrogen phosphate HPO₄ 2-<br />

Ammonium NH₄ 1+<br />

Acetate C₂H₃O₂ 1-<br />

Perchlorate ClO₄ 1-<br />

Permanganate MnO₄ 1-<br />

Chlorate ClO₃ 1-<br />

Hydrogen Sulfate HSO₄ 1-<br />

Phosphite PO₃ 3-<br />

Sulfite SO₃ 2-<br />

Silicate SiO₃ 2-<br />

Nitrate NO₃ 1-<br />

Hydrogen Sulfite HSO₃ 1-<br />

Oxalate C₂O₄ 2-<br />

Cyanide CN 1-<br />

Hydronium H₃O 1+<br />

Thiosulfate S₂O₃ 2-<br />

70


Orbitals Equation Lone Pairs Angle<br />

Name<br />

sp Ax2 None 180 Linear molecular geometry<br />

sp 2 Ax3 None 120 Triangle planar<br />

sp 2 Ax2E 1 116 Bent<br />

sp 3 Ax4 None 109.5 Tetrahedral<br />

sp 3 Ax3E 1 107 Trig pyramidal<br />

sp 3 Ax2E2 2 104.5 Bent<br />

sp 3 d Ax5 None 120/90 Trig bipyramidal<br />

sp 3 d Ax3E2 2 90 T-shaped<br />

sp 3 d Ax6 None 90 octahedral<br />

Sp 3 d 2 Ax4E2 2 90 Square planar<br />

71


Name<br />

Emisael vega<br />

MUSTANG LABORATORIES<br />

EXPERIMENT 6 – Molecular Geometry<br />

Date<br />

In this lab you will use the website https://phet.colorado.edu/sims/html/moleculeshapes/latest/molecule-shapes_en.html.<br />

You will construct the following 10 molecular<br />

compounds using the rules of VSEPR. Use the snip it tool to get pictures of the model<br />

from the side and from the top showing its form. Place these pictures in the appropriate<br />

boxes. You can either do the diagram by hand and take a picture or you can construct<br />

it in this program. Then you will fill in the rest of the form with the relevant information.<br />

I have given you an example.<br />

H 3 O + O 3 SF 6<br />

PF 5 CO 2 OF 2<br />

COCl 2 XeF 4 ClF 3<br />

POF 3<br />

When you have finished save this as a pdf and put it in the drop box in Angel.<br />

Example:<br />

Xenon Hexaflouride<br />

Chemical Name<br />

XeF 6<br />

Chemical Formula<br />

Octahedral<br />

sp 3 d 2<br />

Molecular Geometry<br />

None<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

72


Carbon dioxide<br />

Chemical Name<br />

CO 2<br />

Chemical Formula<br />

Linear<br />

sp<br />

Molecular Geometry<br />

None<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

Cobalt (II) chloride<br />

Chemical Name<br />

CoCl 2<br />

Chemical Formula<br />

Trigonal Planar<br />

Sp 2<br />

Molecular Geometry<br />

None<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

73


Trioxide<br />

Chemical Name<br />

O 3<br />

Chemical Formula<br />

Bent<br />

Molecular Geometry<br />

Sp 2 1<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

Phosphorly fluoride<br />

Chemical Name<br />

PoF 3<br />

Chemical Formula<br />

Tetrahedral<br />

Sp 3<br />

Molecular Geometry<br />

None<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

74


Hydronium<br />

Chemical Name<br />

H 3 O +<br />

Chemical Formula<br />

Trigonal Pyramidal<br />

Molecular Geometry<br />

sp 3 1<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

Oxygen Difluoride<br />

Chemical Name<br />

OF 2<br />

Chemical Formula<br />

Bent<br />

Molecular Geometry<br />

Sp 3 2<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

75


Phosphorus Pentafluoride<br />

Chemical Name<br />

PF 5<br />

Chemical Formula<br />

Trigonal Bipyramidal<br />

Sp 3 d<br />

Molecular Geometry<br />

None<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

Chlorine Triflouride<br />

Chemical Name<br />

ClF 3<br />

Chemical Formula<br />

T-Shaped<br />

Molecular Geometry<br />

SP 3 d 2<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

76


Sulfur hexafluoride<br />

Chemical Name<br />

Sf 6<br />

Chemical Formula<br />

Octahedral<br />

Sp 3 d 2<br />

Molecular Geometry<br />

none<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

Xenon Tetraflouride<br />

Chemical Name<br />

XEF 4<br />

Chemical Formula<br />

Square Planar<br />

Molecular Geometry<br />

Sp 3 d 2 2<br />

Side View<br />

Orbitals<br />

Lone Pairs<br />

Molecular Drawing<br />

With Angles<br />

Top View<br />

77


Finding Bond Angles, Shapes, and Hybridizations<br />

Sometimes people have a hard time with the whole VSEPR thing. In this helpdesk section we'll<br />

discuss what VSEPR means, what it's all about, and how you can use a great big flow chart to figure<br />

out the bond angles, shapes, and hybridizations of various covalent compounds.<br />

This whole thing assumes, by the way, that you know how to draw Lewis structures. If you don't, click<br />

here.<br />

What is VSEPR?<br />

VSEPR stands for Valence Shell Electron Pair Repulsion. It's a complicated acronym, but it means<br />

something that's not difficult to understand. Basically, the idea is that covalent bonds and lone pair<br />

electrons like to stay as far apart from each other as possible under all conditions. This is because<br />

covalent bonds consist of electrons, and electrons don't like to hang around next to each other much<br />

because they have the same charge.<br />

This VSEPR thing explains why molecules have their shapes. If carbon has four atoms stuck to it (as<br />

in methane), these four atoms want to get as far away from each other as they can. This isn't<br />

because the atoms necessarily hate each other, it's because the electrons in the bonds hate each<br />

other. That's the idea behind VSEPR.<br />

What is hybridization (AP <strong>Chemistry</strong>)?<br />

Now, one problem with the whole VSEPR thing is that if you have four things stuck to carbon, for<br />

example, there are no orbitals that want to get 109.5 degrees apart from each other (109.5 degrees<br />

corresponds to the geometric maximum distance the atoms can get apart). After all, s-orbitals go in a<br />

complete sphere (360 degrees) and p-orbitals are 90 degrees apart.<br />

What happens instead of using s- or p- orbitals is that when covalent bonds are formed, the s- and p-<br />

orbitals mix to form something called hybrid orbitals. "Hybrid" just means "mixture of two different<br />

things", and that's exactly what a hybrid orbital is. When three p-orbitals with 90 degree angles<br />

combine with one s-orbital with 360 degrees, they average to form four sp3 orbitals with 109.5 degree<br />

bond angles. Depending on the numbers of s- and p-orbitals that mix, you can get a bunch of<br />

different bond angles.<br />

Common shapes you should know<br />

There are a whole bunch of common shapes you need to know to accurately think of covalent<br />

molecules. Here they are:<br />

Tetrahedral: Tetrahedral molecules look like pyramids with four faces. Each point on the pyramid<br />

corresponds to an atom that's attached to the central atom. Bond angles are 109.5 degrees.<br />

Trigonal pyramidal: It's like a tetrahedral molecule, except flatter. It looks kind of like a squished<br />

pyramid because one of the atoms in the pyramid is replaced with a lone pair. Bond angles are 107.5<br />

degrees (it's less than tetrahedral molecules because the lone pair shoves the other atoms closer to<br />

each other).<br />

Trigonal planar: It looks like the hood ornament of a Mercedes automobile, or like a peace sign with<br />

that bottom-most line gone. The bond angles are 120 degrees.<br />

78


Bent: They look, well, bent. Bond angles can be either 116 degrees for molecules with one lone pair<br />

or 104.5 degrees for molecules with two lone pairs.<br />

Linear: The atoms in the molecule are in a straight line. This can be either because there are only<br />

two atoms in the molecule (in which case there is no bond angle, as there need to be three atoms to<br />

get a bond angle) or because the three atoms are lined up in a straight line (corresponding to a 180<br />

degree bond angle).<br />

There are other types, but we won't worry about them until college or AP <strong>Chemistry</strong>.<br />

Using a flow chart to figure out what shape, and bond angle an atom has<br />

Take a look at this flow chart. I'll explain how to use it to find all the stuff above at the end.<br />

Complicated, huh? Here's how to use it:<br />

1. Draw the Lewis structure for the molecule. This vital if you're going to get the answer right.<br />

2. Count the number of "things" on the atom you're interested in. Let's say that you're looking at<br />

methane, CH4. If you want to find the bond angles, shape, and hybridization for carbon, count<br />

the number of things that are stuck to it.<br />

Now, the vague term "things" refers to atoms and lone pairs. IT DOES NOT REFER TO THE<br />

NUMBER OF BONDS! When you look at methane, there are four atoms stuck to it, so you'd go down<br />

the line that says "four" toward the green boxes on this chart.<br />

People get confused with multiple bonds. Take carbon dioxide, for example. There are four bonds<br />

(carbon is double-bonded to each oxygen) but only two oxygen atoms bonded to carbon. In this<br />

79


case, we count two things stuck to carbon, because we only count the atoms, NOT the number of<br />

bonds.<br />

Likewise, with ammonia there are four things. Three of the things on nitrogen are hydrogen atoms<br />

and the fourth is a lone pair. For the purposes of VSEPR, lone pairs count exactly the same as<br />

atoms, because they consist of negative charge, too.<br />

3. Count the number of lone pairs that are on the atom you're interested in. IMPORTANT: This<br />

does NOT mean to count the number of lone pairs on all of the atoms in the molecule. Lone<br />

pairs on other atoms aren't important - what's important is only what's directly stuck to the atom<br />

you're interested in.<br />

We mentioned above that methane has four things stuck to it. Since all four things are hydrogen<br />

atoms, we moved toward the green boxes on the flow chart. When we get to our second question,<br />

we find that there are no lone pairs on carbon, so our answer is zero. When we go down the line that<br />

says "zero" from that box, we find that methane is sp3 hybridized, with a 109.5 degree bond angle<br />

and tetrahedral shape.<br />

And, hey, that's what we were looking for!<br />

Some sample problems:<br />

What are the shapes, bond angles, and hybridizations of the following molecules? Use the flow chart<br />

and instructions above to figure it out.<br />

1. carbon tetrabromide<br />

Tetrahedral<br />

109.5<br />

Sp 3<br />

2. phosphorus trichloride<br />

Trigonal pyramidal<br />

Sp 3c<br />

107<br />

3. oxygen<br />

Linear<br />

Sp 2<br />

No angle<br />

80


4. the chlorine atom in hydrochloric acid (HCl)<br />

sp3,<br />

Linear,<br />

no angle<br />

5. boron trichloride<br />

sp2<br />

Trigonal planar<br />

120 degrees<br />

6. CH2O<br />

sp2,<br />

Trigonal planar<br />

120 degrees<br />

7. sulfur difluoride<br />

sp3<br />

Bent<br />

104.5 degrees<br />

8. either carbon atom in C2H2<br />

sp<br />

linear<br />

180 degrees<br />

1. sp 3 , tetrahedral, 109.5 degrees.<br />

2. sp 3 , trigonal pyramidal, 107.5 degrees.<br />

3. sp 2 , linear, no bond angle<br />

4. sp 3 , linear, no bond angle<br />

5. sp 2 , trigonal planar, 120 degrees<br />

6. sp 2 , trigonal planar, 120 degrees<br />

7. sp 3 , bent, 104.5 degrees<br />

8. sp, linear, 180 degrees<br />

81


Unit 4<br />

Chapter 22 Hydrocarbon Compounds<br />

The student will learn how Hydrocarbons are named and the<br />

general properties of Hydrocarbons.<br />

Describe how different natural resources are produced and how their rates<br />

of use and renewal limit availability.<br />

Students will explore local, national, and global renewable and nonrenewable<br />

resources.<br />

Students will explain the environmental costs of the use of renewable and<br />

nonrenewable resources.<br />

Students will explain the benefits of renewable and nonrenewable resources.<br />

Nuclear reactors<br />

Natural gas<br />

Petroleum<br />

Refining<br />

Coal<br />

82


Chapter 23 Functional Groups<br />

The student will learn what effects functional groups have on<br />

organic compounds and how chemical reactions are used in<br />

organic compounds.<br />

Describe the properties of the carbon atom that make the diversity of carbon<br />

compounds possible.<br />

Identify selected functional groups and relate how they contribute to<br />

properties of carbon compounds.<br />

Students will identify examples of important carbon based molecules.<br />

Students will create 2D or 3D models of carbon molecules and explain why this<br />

molecule is important to life.<br />

covalent bond<br />

single bond<br />

double bond<br />

triple bond<br />

monomer<br />

polymer<br />

83


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https://www.bbc.co.uk/education/guides/zvvwxnb/revision


85


Introduction to Organic <strong>Chemistry</strong><br />

To understand life as we know it, we must first understand a little bit of organic chemistry. Organic<br />

molecules contain both carbon and hydrogen. Though many organic chemicals also contain other<br />

elements, it is the carbon-hydrogen bond that defines them as organic. Organic chemistry defines life.<br />

Just as there are millions of different types of living organisms on this planet, there are millions of<br />

different organic molecules, each with different chemical and physical properties. There are organic<br />

chemicals that make up your hair, your skin, your fingernails, and so on. The diversity of organic<br />

chemicals is due to the versatility of the carbon atom. Why is carbon such a special element? Let's<br />

look at its chemistry in a little more detail.<br />

The uniqueness of carbon<br />

Carbon (C) appears in the second row of the periodic table and has four bonding electrons in its<br />

valence shell (see our Periodic Table module for more information). Similar to other non-metals,<br />

carbon needs eight electrons to satisfy its valence shell. Carbon therefore forms four bonds with other<br />

atoms (each bond consisting of one of carbon's electrons and one of the bonding atom's electrons).<br />

Every valence electron participates in bonding; thus, a carbon atom's bonds will be distributed evenly<br />

over the atom's surface. These bonds form a tetrahedron (a pyramid with a spike at the top), as<br />

illustrated below:<br />

Carbon forms 4 bonds<br />

Organic chemicals get their diversity from the many different ways carbon can bond to other atoms.<br />

The simplest organic chemicals, called hydrocarbons, contain only carbon and hydrogen atoms; the<br />

simplest hydrocarbon (called methane) contains a single carbon atom bonded to four hydrogen<br />

atoms:<br />

Methane - a carbon atom bonded to 4 hydrogen atoms<br />

But carbon can bond to other carbon atoms in addition to hydrogen, as illustrated in the molecule<br />

ethane below:<br />

Ethane - a carbon-carbon bond<br />

In fact, the uniqueness of carbon comes from the fact that it can bond to itself in many different ways.<br />

Carbon atoms can form long chains:<br />

86


anched chains:<br />

Hexane - a 6-carbon chain<br />

rings:<br />

Isohexane - a branched-carbon chain<br />

Cyclohexane - a ringed hydrocarbon<br />

There appears to be almost no limit to the number of different structures that carbon can form. To add to the<br />

complexity of organic chemistry, neighboring carbon atoms can form double and triple bonds in addition to<br />

single carbon-carbon bonds:<br />

Single bonding Double bonding Triple bonding<br />

Keep in mind that each carbon atom forms four bonds. As the number of bonds between any two<br />

carbon atoms increases, the number of hydrogen atoms in the molecule decreases (as can be seen<br />

in the figures above).<br />

Simple hydrocarbons<br />

The simplest hydrocarbons are those that contain only carbon and hydrogen. These simple<br />

hydrocarbons come in three varieties depending on the type of carbon-carbon bonds that occur in the<br />

molecule.<br />

Alkanes<br />

Alkanes are the first class of simple hydrocarbons and contain only carbon-carbon single bonds. The<br />

alkanes are named by combining a prefix that describes the number of carbon atoms in the molecule<br />

with the root ending "ane". The names and prefixes for the first ten alkanes are given in the following<br />

table.<br />

87


Carbon Prefix Alkane Name Chemical Structural Formula<br />

atoms<br />

Formula<br />

1 Meth Methane CH4 CH4<br />

2 Eth Ethane C2H6 CH3CH3<br />

3 Prop Propane C3H8 CH3CH2CH3<br />

4 But Butane C4H10 CH3CH2CH2CH3<br />

5 Pent Pentane C5H12 CH3CH2CH2CH2CH3<br />

6 Hex Hexane C6H14 …<br />

7 Hept Heptane C7H16<br />

8 Oct Octane C8H18<br />

9 Non Nonane C9H20<br />

10 Dec Decane C10H22<br />

The chemical formula for any alkane is given by the expression CnH2n+2. The structural formula,<br />

shown for the first five alkanes in the table, shows each carbon atom and the elements that are<br />

attached to it. This structural formula is important when we begin to discuss more complex<br />

hydrocarbons. The simple alkanes share many properties in common. All enter into combustion<br />

reactions with oxygen to produce carbon dioxide and water vapor. In other words, many alkanes are<br />

flammable. This makes them good fuels. For example, methane is the main component of natural<br />

gas, and butane is common lighter fluid.<br />

CH4 + 2O2 → CO2 + H2O<br />

The chemical reaction between a fuel (for example wood) and an oxidation agent.<br />

Alkenes<br />

The second class of simple hydrocarbons, the alkenes, consists of molecules that contain at least<br />

one double-bonded carbon pair. Alkenes follow the same naming convention used for alkanes. A<br />

prefix (to describe the number of carbon atoms) is combined with the ending "ene" to denote an<br />

alkene. Ethene, for example is the two-carbon molecule that contains one double bond. The chemical<br />

formula for the simple alkenes follows the expression CnH2n. Because one of the carbon pairs is<br />

double bonded, simple alkenes have two fewer hydrogen atoms than alkanes.<br />

Ethene<br />

Alkynes<br />

Alkynes are the third class of simple hydrocarbons and are molecules that contain at least one triplebonded<br />

carbon pair. Like the alkanes and alkenes, alkynes are named by combining a prefix with the<br />

ending "yne" to denote the triple bond. The chemical formula for the simple alkynes follows the<br />

expression CnH2n-2.<br />

Ethyne<br />

88


Isomers<br />

Because carbon can bond in so many different ways, a single molecule can have different bonding<br />

configurations. Consider the two molecules illustrated here:<br />

C6H14<br />

CH3CH2CH2CH2CH2CH3<br />

C6H14<br />

CH3<br />

I<br />

CH2CH2CH2CH2CH3<br />

Both molecules have identical chemical formulas (shown in the left column); however, their structural<br />

formulas (and thus some chemical properties) are different. These two molecules are called isomers.<br />

Isomers are molecules that have the same chemical formula but different structural formulas.<br />

Functional groups<br />

In addition to carbon and hydrogen, hydrocarbons can also contain other elements. In fact, many<br />

common groups of atoms can occur within organic molecules, these groups of atoms are called<br />

functional groups. One good example is the hydroxyl functional group. The hydroxyl group consists of<br />

a single oxygen atom bound to a single hydrogen atom (OH - ). The group of hydrocarbons that contain<br />

a hydroxyl functional group is called alcohols. The alcohols are named in a similar fashion to the<br />

simple hydrocarbons, a prefix is attached to a root ending (in this case "anol") that designates the<br />

alcohol. The existence of the functional group completely changes the chemical properties of the<br />

molecule. Ethane, the two-carbon alkane, is a gas at room temperature; ethanol, the two-carbon<br />

alcohol, is a liquid.<br />

Ethanol<br />

Ethanol, common drinking alcohol, is the active ingredient in "alcoholic" beverages such as beer and<br />

wine.<br />

Summary<br />

The chemical basis of all living organisms is linked to the way that carbon bonds with other atoms.<br />

This introduction to organic chemistry explains the many ways that carbon and hydrogen form bonds.<br />

Basic hydrocarbon nomenclature is described, including alkanes, alkenes, alkynes, and isomers.<br />

Functional groups of atoms within organic molecules are discussed.<br />

89


Unit 5<br />

Chapter 10 Chemical Quantities<br />

The student will learn why the mole is important and how the<br />

molecular formula of a compound can be determined<br />

experimentally.<br />

Chapter 11 Chemical Reactions<br />

The students will learn how chemical reactions obey the law of<br />

conservation of mass and how they can predict the products<br />

of a chemical reaction.<br />

Characterize types of chemical reactions, for example: redox, acid-base,<br />

synthesis, and single and double replacement reactions.<br />

Students will be able to identify the type of chemical reaction that occurs.<br />

Students will be able to compare/contrast reactants and products of various<br />

types of chemical reactions.<br />

Students will be able to predict the product of various reactants.<br />

Students will be able to write balanced chemical equations for each type of<br />

reaction.<br />

Decomposition<br />

Combustion<br />

Redox<br />

Acid-Base<br />

Synthesis<br />

single-replacement<br />

double-replacement<br />

Differentiate between chemical and nuclear reactions.<br />

Students will compare/contrast chemical and nuclear reactions.<br />

fission<br />

fusion<br />

90


Chapter 12 Stoichiometry<br />

The students will learn how balanced chemical equations are<br />

used in stoichiometric calculations and how to calculate<br />

amounts of reactants and products in a chemical equation.<br />

Apply the mole concept and the law of conservation of mass to calculate<br />

quantities of chemicals participating in reactions.<br />

Students will be able to use a balanced equation to determine mole ratios.<br />

Students will be able to apply law of conservation of mass to chemical equations.<br />

Students will be able to calculate empirical and molecular formulas.<br />

Students will be able to calculate the % composition of a compound.<br />

Students will be able to calculate theoretical yield.<br />

Students will be able to calculate % error.<br />

Students will be able to calculate molar mass.<br />

Students will be able to perform stoichiometric calculations, including limiting<br />

reagents.<br />

mole<br />

Avogadro’ s number<br />

molar mass<br />

gram formula mass<br />

91


Learning Goal for this section:<br />

The student will learn why the mole is important and how themolecular formula of a compound can be determined<br />

experimentally.<br />

The Mole: Its History and Use<br />

Simply put, the mole represents a number. Just as the term dozen refers to the number twelve, the<br />

mole represents the number 6.02 x 10 23 . (If you're confused by the form of this number refer to our<br />

The Metric System module).<br />

Now that's a big number! While a dozen eggs will make a nice omelet, a mole of eggs will fill all of the<br />

oceans on earth more than 30 million times over. Think about it: It would take 10 billion chickens<br />

laying 10 eggs per day more than 10 billion years to lay a mole of eggs. So why would we ever use<br />

such a big number? Certainly the local donut store is not going to "supersize" your dozen by giving<br />

you a mole of jelly-filled treats.<br />

The mole is used when we're talking about numbers of atoms and molecules. Atoms and molecules<br />

are very tiny things. A drop of water the size of the period at the end of this sentence would contain<br />

10 trillion water molecules. Instead of talking about trillions and quadrillions of molecules (and more),<br />

it's much simpler to use the mole.<br />

History of the mole<br />

The number of objects in one mole, that is, 6.02 x 10 23 , is commonly referred to as Avogadro's<br />

number. Amedeo Avogadro was an Italian physics professor who proposed in 1811 that equal<br />

volumes of different gases at the same temperature contain equal numbers of molecules. About fifty<br />

years later, an Italian scientist named Stanislao Cannizzaro used Avogadro's hypothesis to develop a<br />

set of atomic weights for the known elements by comparing the masses of equal volumes of gas.<br />

Building on this work, an Austrian high school teacher named Johann Josef Loschmidt calculated the<br />

size of a molecule of air in 1865, and thus developed an estimate for the number of molecules in a<br />

given volume of air. While these early estimates have since been refined, they led to the concept of<br />

the mole - that is, the theory that in a defined mass of an element (its atomic weight) there is a<br />

precise number of atoms: Avogadro's number.<br />

Molar mass<br />

A sample of any element with a mass equal to that element's atomic weight (in grams) will contain<br />

precisely one mole of atoms (6.02 x 10 23 atoms). For example, helium has an atomic weight of 4.00<br />

amu. Therefore, 4.00 grams of helium will contain one mole of helium atoms. You can also work with<br />

fractions (or multiples) of moles:<br />

Mole/weight relationship<br />

examples using helium<br />

moles<br />

helium<br />

# helium<br />

atoms<br />

grams<br />

helium<br />

¼ 1.505 X 10 23 1g<br />

½ 3.01 X 10 23 2g<br />

1 6.02 X 10 23 4g<br />

2 1.204 X 10 24 8g<br />

10 6.02 X 10 24 40g<br />

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Other atomic weights are listed on the periodic table (see our Periodic Table module). For each<br />

element listed, measuring out a quantity of the element equal to its atomic weight in grams will yield<br />

6.02 x 10 23 atoms of that element.<br />

The atomic weight of an element identifies both the mass of one mole of that element and the total<br />

number of protons and neutrons in an atom of that element. How can that be? Let's look at hydrogen.<br />

One mole of hydrogen atoms will weigh 1.01 grams.<br />

A hydrogen atom<br />

with its single electron<br />

Each hydrogen atom consists of one proton surrounded by one electron. But remember, the electron<br />

weighs so little that it does not contribute much to an atom's weight. Ignoring the weight of hydrogen's<br />

electrons, we can say that one mole of protons (H nuclei) weighs approximately one gram. Since<br />

protons and neutrons have about the same mass, a mole of either of these particles will weigh about<br />

one gram. For example, in one mole of helium, there are two moles of protons and two moles of<br />

neutrons - four grams of particles.<br />

Molecular weight<br />

If you stand on a scale with a friend, the scale will register the combined weight of both you and your<br />

friend. When atoms form molecules, the atoms bond together, and the molecule's weight is the<br />

combined weight of all of its parts.<br />

For example, every water molecule (H2O) has two atoms of hydrogen and one atom of oxygen. One<br />

mole of water molecules will contain two moles of hydrogen and one mole of oxygen.<br />

2 moles<br />

hydrogen<br />

Mole/weight relationships<br />

of water and its parts<br />

1 mole<br />

oxygen<br />

1 mole<br />

water<br />

+ =<br />

A bottle filled with exactly 18.02 g water will contain 6.02 x 10 23 water molecules. The concept of<br />

fractions and multiples described above also applies to molecules: 9.01 g of water would contain 1/2<br />

mole, or 3.01 x 10 23 molecules. You can calculate the molecular weight of any compound simply by<br />

summing the weights of atoms that make up that compound.<br />

93


Example: Converting between mass and moles<br />

Knowing a substance’s molar mass is useful, because the molar mass acts as a conversion factor<br />

between the mass of a sample and the number of moles in that sample (Equation 1). For converting<br />

between the number of moles in a sample and the number of molecules in the sample, Avogadro’s<br />

number acts as the conversion factor, as shown in Equation 2 below.<br />

Equation 1<br />

Sample mass (g) = Moles in sample (mol)<br />

Sample's molar mass (g/mol)<br />

Equation 2<br />

Moles in sample (mol) x Avogadro's number (number/mol) = Number of sample molecules<br />

To understand how molar mass and Avogadro’s number act as conversion factors, we can turn to an<br />

example using a popular drink: How many CO2 molecules are in a standard bottle of carbonated<br />

soda?<br />

Thanks to molar mass and Avogadro’s number, figuring this out doesn’t require counting each<br />

individual CO2 molecule! Instead, we can start by determining the mass of CO2 in this sample. In an<br />

experiment, a scientist compared the mass of a standard 16-ounce (454 milliliters) bottle of soda<br />

before it was opened, and then after it had been shaken and left open so that the CO2 fizzed out of<br />

the liquid. The difference between the masses was 2.2 grams—the sample mass of CO2 (for this<br />

example, we’re going to assume that all the CO2 has fizzled out). Before we can calculate the number<br />

of CO2 molecules in 2.2 grams, we first have to calculate the number of moles in 2.2 grams of CO2<br />

using molar mass as the conversion factor (see Equation 1 above):<br />

Equation 3<br />

Now that we’ve figured out that there are 0.050 moles in 2.2 grams of CO2, we can use Avogadro’s<br />

number to calculate the number of CO2 molecules (see Equation 2 above):<br />

Equation 4<br />

While scientists today commonly use the concept of the mole to interconvert number of particles and<br />

mass of elements and compounds, the concept started with 19th-century chemists who were puzzling<br />

out the nature of atoms, gas particles, and those particles’ relationship with gas volume.<br />

94


Find Molecular Mass 1- 10<br />

1. NaBr<br />

NA 1 * 23= 23<br />

Br 1 * 80= 80 = 103 g/,ol<br />

2. PbSO4<br />

3. Zn(C2H3O2)2<br />

4. Na3PO4<br />

Pb 1* 207= 207<br />

S 1*32= 32<br />

O 4*16 = 64 = 303g/mol<br />

Zn 1 * 65 =65<br />

C 4* 12 = 48<br />

H 6* 1 = 6<br />

O 4 * 16 = 64 = 183g/mol<br />

Na 3* 23= 69<br />

P 1* 31= 31<br />

O 4* 16 =64 = 164g/mol<br />

5. (NH4)2CO3<br />

6. Glucose<br />

C H O<br />

6 12 6<br />

7. Iron(II) Phosphate<br />

N 2* 14=28<br />

H 8* 1=8<br />

C 1* 12=12<br />

O 3* 16= 48 = 96 g/mol<br />

C 6 * 12= 72<br />

H 12 * 1= 12<br />

O 6 * 16 = 96 = 180g/mol<br />

Fe 3*56=168<br />

P 2 * 31=62<br />

O 8*16=128 = 358 g/mol<br />

Fe (PO )<br />

3<br />

4 2<br />

8. Ammonium Sulfide<br />

N 2* 14= 28<br />

(NH 4) 2S<br />

H 8* 1= 8<br />

S 1* 32=32 = 68 g/mol<br />

9. Calcium Hydroxide<br />

10. Silver(I) Fluoride<br />

Ca(OH)2<br />

Ca 1* 40= 40<br />

O 2*16= 32<br />

H 2* 1=2 = 74g/mol<br />

AgF<br />

Ag 1*108= 108<br />

F 1*19=19 = 127g/mol<br />

11. How many moles is 51g of NaBr?<br />

12. How many moles is 60g of PbSO4?<br />

13. How many moles is 150g of Zn(C2H3O2)2?<br />

51g/mol NaBr<br />

60g/mol PbSo<br />

4<br />

1 mol NaBr<br />

103g/mol NaBr<br />

1 mol PbSO<br />

4<br />

303g/mol PbSO4<br />

= 51 mol<br />

= 103<br />

= .495 = .50 mol NaBr<br />

= 60 mol<br />

= .19801 =. 20 mol PbSO<br />

=303<br />

150g/mol Zn(C 2H 3O 2<br />

) 2 1 mole Zn(C 2 H 3 O 2 ) 2 = 150 mol<br />

183g/mol Zn(C H O ) = 183<br />

= .8196 = .82 mol Zn(C H O )<br />

2 3 2 3 2<br />

2<br />

2<br />

2<br />

4<br />

14. How many moles is 578g of Na3PO4?<br />

578g/mol Na 3PO<br />

4<br />

1mol Na<br />

3<br />

PO 4<br />

164g/mol Na PO<br />

= 578<br />

= 164<br />

= 3.5243 = 3.5 mol Na PO<br />

3 4<br />

15. How many moles is 500g of (NH4)2CO3?<br />

500g/mol (NH ) CO<br />

1 mol (NH ) CO<br />

4 2 3 4 2 3<br />

96g/mol (NH ) CO<br />

4 2<br />

3<br />

= 5.2088 = 5.2 mol (NH ) CO<br />

4<br />

2 3<br />

1. 103 g/mol 6. 180 g/mol 11. .50 mol<br />

2. 303 g/mol 7. 358 g/mol 12. .20 mol<br />

3. 74 g/mol 8. 68 g/mol 13. 2.0 mol<br />

4. 164 g/mol 9. 183 g/mol 14. 3.5 mol<br />

5. 96 g/mol 10. 127 g/mol 15. 5.2 mol<br />

95


The Learning Goal for this assignment is:<br />

The students will learn how balanced chemical equations are used in stoichiometric calculations and how to calculate<br />

amounts of reactants and products in a chemical equation.<br />

How to Balance Chemical Equations<br />

A chemical equation is a theoretical or written representation of what happens during a chemical<br />

reaction. The law of conservation of mass states that no atoms can be created or destroyed in a<br />

chemical reaction, so the number of atoms that are present in the reactants has to balance the<br />

number of atoms that are present in the products. Follow this guide to learn how to balance chemical<br />

equations.<br />

Step 1<br />

Write down your given equation. For this example, we will use:<br />

C3H8 + O2 --> H2O + CO2<br />

Step 2<br />

Write down the number of atoms that you have on each side of the equation. Look at the subscripts<br />

next to each atom to find the number of atoms in the equation.<br />

Left side: 3 carbon, 8 hydrogen and 2 oxygen<br />

96


Right side: 1 carbon, 2 hydrogen and 3 oxygen<br />

Step 3<br />

Always leave hydrogen and oxygen for last. This means that you will need to balance the carbon<br />

atoms first.<br />

Step 4<br />

Add a coefficient to the single carbon atom on the right of the equation to balance it with the 3 carbon<br />

atoms on the left of the equation.<br />

C3H8 + O2 --> H2O + 3CO2<br />

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The coefficient 3 in front of carbon on the right side indicates 3 carbon atoms just as the subscript 3<br />

on the left side indicates 3 carbon atoms.<br />

In a chemical equation, you can change coefficients, but you should never alter the subscripts.<br />

Step 5<br />

Balance the hydrogen atoms next. You have 8 on the left side, so you'll need 8 on the right side.<br />

C3H8 + O2 --> 4H2O + 3CO2<br />

On the right side, we added a 4 as the coefficient because the subscript showed that we already<br />

had 2 hydrogen atoms.<br />

When you multiply the coefficient 4 times the subscript 2, you end up with 8.<br />

Step 6<br />

Finish by balancing the oxygen atoms.<br />

Because we've added coefficients to the molecules on the right side of the equation, the number of<br />

oxygen atoms has changed. We now have 4 oxygen atoms in the water molecule and 6 oxygen<br />

atoms in the carbon dioxide molecule. That makes a total of 10 oxygen atoms.<br />

98


Add a coefficient of 5 to the oxygen molecule on the left side of the equation. You now have 10<br />

oxygen molecules on each side.<br />

C3H8 + 5O2 --> 4H2O + 3CO2.<br />

The carbon, hydrogen and oxygen atoms are balanced. Your equation is complete.<br />

1) _2__ NaNO3 + ___ PbO ___ Pb(NO3)2 + ___ Na2O<br />

2) ___ 6 AgI + ___ Fe2(CO3)3 ___ 2 Fel3 + ___ 3 Ag2CO3<br />

3) ___ C2H4O2 + ___ 2 O2 ___ 2 CO2 + ___ 2 H2O<br />

4) ___ ZnSO4 + ___ Li2CO3 ___ ZnCO3 + ___ Li2SO4<br />

5) ___ V2O5 + ___ 5 CaS ___ 5 CaO + ___ V2S5<br />

99


6) ___ Mn(NO2)2 + ___ BeCl2 ___ Be(NO2)2 + ___ MnCl2<br />

7) ___ 3 AgBr + ___ GaPO4 ___ Ag3PO4 + ___ GaBr3<br />

8) ___ 3 H2SO4 + ___ 2 B(OH)3 __ B2(SO4)3 + ___ 6 H2O<br />

6<br />

12<br />

12<br />

9) ___ S8 + ___ 8 O2 ___ 8 SO2<br />

10) ___ Fe + ___ 2 AgNO3 ___ Fe(NO3)2 + ___ 2 Ag<br />

100


1) 2 NaNO3 + PbO Pb(NO3)2 + Na2O<br />

2) 6 AgI + Fe2(CO3)3 2 FeI3 + 3 Ag2CO3<br />

3) C2H4O2 + 2 O2 2 CO2 + 2 H2O<br />

4) ZnSO4 + Li2CO3 ZnCO3 + Li2SO4<br />

5) V2O5 + 5 CaS 5 CaO + V2S5<br />

6) Mn(NO2)2 + BeCl2 Be(NO2)2 + MnCl2<br />

7) 3 AgBr + GaPO4 Ag3PO4 + GaBr3<br />

8) 3 H2SO4 + 2 B(OH)3 B2(SO4)3 + 6 H2O<br />

9) S8 + 8 O2 8 SO2<br />

10) Fe + 2 AgNO3 Fe(NO3)2 + 2 Ag<br />

Additional Notes:<br />

The law of conservation of mass says that atoms cannot be created or destroyed in a chemical<br />

reaction. Most importantly the number of atoms has to balance the number of atoms that are present<br />

in the products IN order to balance chemical equation, you must make the reaction and the product<br />

equal to each other or else you won’t get it right. And there is sometimes you deal with Decimals, but<br />

you must multiply everything by the number that makes it A whole number. Another helpful thing to<br />

do is to always leave hydrogen and oxygen for last.<br />

Example<br />

_4__C2h7n+_19_ O2 =>__8_ CO2 + _14__ H2O+ _4__ NO2<br />

4 4 7 4<br />

C 2 8 C 1 2 8<br />

N 1 4 N 1 2 4<br />

H 7 28 H 2 28<br />

O 2 38 O 4 6 8 38<br />

You write the number of atoms you have on each side of each equation of each individual element. You need to<br />

look at the subscripts. Next you should Try to make the product c Multiply by two to make the first one equal but<br />

make the O oxygen change because you multiplied everything with carbon. Furthermore, multiply the product of N<br />

by 2 to make it equal the same as reaction Then you multiply reaction by 3 to get the same number 6 as oxygen in<br />

the product. \Then you just keep on building on that to get each side the same amount in each element.<br />

101


102<br />

The Learning Goal for this assignment is: The students will learn how chemical reactions obey the law<br />

of conservation of mass and how they can predict the products of a chemical reaction<br />

Categories of<br />

Reactions<br />

All chemical reactions can be placed into one of six categories. Here they are, in no<br />

particular order:<br />

1) Synthesis: A synthesis reaction is when two or more simple compounds combine to form a<br />

more complicated one. These reactions come in the general form of:<br />

A+B=>AB<br />

One example of a synthesis reaction is the combination of iron and sulfur to form iron (II) sulfide:<br />

8 Fe + S 8 ---> 8 FeS<br />

If two elements or very simple molecules combine with each other, it’s probably a synthesis reaction.<br />

The products will probably be predictable using the octet rule to find charges.<br />

2) Decomposition: A decomposition reaction is the opposite of a synthesis reaction - a<br />

complex molecule breaks down to make simpler ones. These reactions come in the general form:<br />

AB =>A+B<br />

One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen<br />

gas:<br />

2 H 2O ---> 2 H 2 + O 2<br />

If one compound has an arrow coming off of it, it’s probably a decomposition reaction. The products<br />

will either be a couple of very simple molecules, or some elements, or both.<br />

3) Single displacement: This is when one element trades places with another element in a<br />

compound. These reactions come in the general form of:<br />

B must metal so c is negative<br />

A+BC=> AC+B OR BA+C<br />

IF its metal it replace non metal<br />

One example of a single displacement reaction is when magnesium replaces hydrogen in water to<br />

make magnesium hydroxide and hydrogen gas:<br />

Mg + 2 H 2O ---> Mg(OH) 2 + H 2<br />

If a pure element reacts with another compound (usually, but not always, ionic), it’s probably a single<br />

displacement reaction. The products will be the compounds formed when the pure element switches<br />

places with another element in the other compound.<br />

Important note: these reactions will only occur if the pure element on the reactant side of the equation<br />

is higher on the activity series than the element it replaces.


4) Double displacement: This is when the anions and cations of two different molecules<br />

switch places, forming two entirely different compounds. These reactions are in the general form:<br />

AB+CD=> AD+CB<br />

One example of a double displacement reaction is the reaction of lead (II) nitrate with potassium<br />

iodide to form lead (II) iodide and potassium nitrate:<br />

Pb(NO 3) 2 + 2 KI ---> PbI 2 + 2 KNO 3<br />

If two ionic compounds combine, it’s probably a double displacement reaction. Switch the cations and<br />

balance out the charges to figure out what will be made.<br />

Important note: These reactions will only occur if both reactants are soluble in water and only one<br />

product is soluble in water.<br />

5) Acid-base: This is a special kind of double displacement reaction that takes place when an<br />

acid and base react with each other. The H + ion in the acid reacts with the OH - ion in the base,<br />

causing the formation of water. Generally, the product of this reaction is some ionic salt and water:<br />

HA+BOH=>BA+H2O<br />

One example of an acid-base reaction is the reaction of hydrobromic acid (HBr) with sodium<br />

hydroxide:<br />

HBr + NaOH ---> NaBr + H 2O<br />

If an acid and a base combine, it’s an acid-base reaction. The products will be an ionic compound<br />

and water.<br />

6) Combustion: A combustion reaction is when oxygen combines with another compound to<br />

form water and carbon dioxide. These reactions are exothermic, meaning they produce heat. An<br />

example of this kind of reaction is the burning of napthalene:<br />

Organic C 10H 8 + 12 O 2 ---> 10 CO 2 + 4 H 2O Org+O2=>CO2=H2O<br />

If something that has carbon and hydrogen reacts with oxygen, it’s probably a combustion reaction.<br />

The products will be CO2 and H2O.<br />

Follow this series of questions. When you can answer "yes" to a question, then<br />

stop!<br />

1) Does your reaction have two (or more) chemicals combining to form one chemical? If yes, then<br />

it's a synthesis reaction<br />

2) Does your reaction have one large molecule falling apart to make several small ones? If yes,<br />

then it's a decomposition reaction<br />

3) Does your reaction have any molecules that contain only one element? If yes, then it's a single<br />

displacement reaction<br />

4) Does your reaction have water as one of the products? If yes, then it's an acid-base reaction<br />

5) Does your reaction have oxygen as one of it's reactants and carbon dioxide and water as<br />

products? If yes, then it's a combustion reaction<br />

6) If you haven't answered "yes" to any of the questions above, then you've got a double<br />

displacement reaction.<br />

103


If a is higher than b it will take place.<br />

If its more active it will replace it.<br />

Show radioactivity of metals.<br />

Both reactants need to be soluble.<br />

Are Soluble. Only one product is<br />

Soluble. OR else we Won’t have a<br />

reaction<br />

Double Displacement<br />

104<br />

List what type the following reactions are:<br />

1) NaOH + KNO3 --> NaNO3 + KOH Double Displacement<br />

AB+CD=>AD+CB<br />

2) CH4 + 2 O2 --> CO2 + 2 H2O Combustion<br />

ORG O2=>CO2+H2O A+BC AC+B<br />

3) 2 Fe + 6 NaBr --> 2 FeBr3 + 6 Na Single Displacement<br />

4) CaSO4 + Mg(OH)2 --> Ca(OH)2 + MgSO4 Double Displacement<br />

AB+CD=>AD+CB<br />

5) NH4OH + HBr --> H2O + NH4Br Acid Base<br />

AOH +HB+H2O+AB<br />

6) Pb + O2 --> PbO2 Synthesis<br />

A+B=>ab<br />

7) Na2CO3 --> Na2O + CO2


Decomposition<br />

ab=>A+B<br />

Determine the Type of Reaction for each equation.<br />

Then predict the products of each of the following chemical reactions. If a reaction will not occur,<br />

explain why not.<br />

Then Balance the equation.<br />

1) __Ag2SO4 + __NaNO3 2 → __AgNo3+___Na2So4<br />

2<br />

NO Reaction, because sulfate is attached to silver only one need to be soluble. Insoluble<br />

Double Displacement<br />

2) __NaI 2 + __CaSO4 → ___Na2So4+CaI2<br />

No reaction because only one is supposed to be Soluble but Two are Sulfate and na. Insoluble<br />

Double Displacement<br />

3) __HNO3 2 + __Ca(OH)2 → ___H2O+___Ca(No3)2<br />

2<br />

It is a reaction which I soluble because it a nitrate in it which has no reaction.<br />

Acid Base<br />

4) __CaCO3 → _____CaO + ___Co2<br />

It’s a reaction because it is carbonate insoluble. Decomposition<br />

5) __AlCl3 + __(NH4)PO4 →___ AL PO 4 +____ NH 4 Cl<br />

Yes, because we need Two to be soluble. Double displacement.<br />

6) __Pb 3 + __Fe(NO3)3 2 → ___ 3 Pb(No3)2+___ 2 Fe<br />

No reaction, because lead is not as reactant that iron . Iron is higher. Insoluble<br />

7) __C3H6 + __O2 →___ C3O2+ ___H6<br />

Its soluble due to the fact that is nitarte No3<br />

combustion<br />

8) __Na 2 + __CaSO4 → ____NASO4 + __CA<br />

2<br />

Reaction Soluble Because it group 1. Single displacement<br />

105


The Learning Goal for this assignment is:<br />

The studenta will learn to balance chemical equations are aused in stoichiometry and how to calculate<br />

amounts of reactants and products in chemical equations.<br />

Stoichiometry and Balancing Reactions<br />

Stoichiometry is a section of chemistry that involves using relationships between reactants and/or<br />

products in a chemical reaction to determine desired quantitative data. In Greek, stoikhein means<br />

element and metron means measure, so stoichiometry literally translated means the measure of<br />

elements. In order to use stoichiometry to run calculations about chemical reactions, it is important to<br />

first understand the relationships that exist between products and reactants and why they exist, which<br />

require understanding how to balanced reactions.<br />

Balancing<br />

In chemistry, chemical reactions are frequently written as an equation, using chemical symbols. The<br />

reactants are displayed on the left side of the equation and the products are shown on the right, with<br />

the separation of either a single or double arrow that signifies the direction of the reaction. The<br />

significance of single and double arrow is important when discussing solubility constants, but we will<br />

not go into detail about it in this module. To balance an equation, it is necessary that there are the<br />

same number of atoms on the left side of the equation as the right. One can do this by raising the<br />

coefficients.<br />

Reactants to Products<br />

A chemical equation is like a recipe for a reaction so it displays all the ingredients or terms of a<br />

chemical reaction. It includes the elements, molecules, or ions in the reactants and in the products as<br />

well as their states, and the proportion for how much of each particle is create relative to one another,<br />

through the stoichiometric coefficient. The following equation demonstrates the typical format of a<br />

chemical equation:<br />

2Na(s) + 2HCl(aq) → 2NaCl(aq) + H2(g)<br />

In the above equation, the elements present in the reaction are represented by their chemical<br />

symbols. Based on the Law of Conservation of Mass, which states that matter is neither created nor<br />

destroyed in a chemical reaction, every chemical reaction has the same elements in its reactants and<br />

products, though the elements they are paired up with often change in a reaction. In this reaction,<br />

sodium (Na), hydrogen (H), and chloride (Cl) are the elements present in both reactants, so based on<br />

the law of conservation of mass, they are also present on the product side of the equations.<br />

Displaying each element is important when using the chemical equation to convert between<br />

elements.<br />

Stoichiometric Coefficients<br />

In a balanced reaction, both sides of the equation have the same number of elements. The<br />

stoichiometric coefficient is the number written in front of atoms, ion and molecules in a chemical<br />

reaction to balance the number of each element on both the reactant and product sides of the<br />

equation. These stoichiometric coefficients are useful since they establish the mole ratio between<br />

reactants and products. In the balanced equation:<br />

2Na(s)+2HCl(aq)→2NaCl(aq)+H2(g)<br />

106


we can determine that 2 moles of HCl will react with 2 moles of Na(s) to form 2 moles of NaCl(aq) and 1<br />

mole of H2(g). If we know how many moles of Na we start out with, we can use the ratio of 2 moles<br />

of NaCl to 2 moles of Na to determine how many moles of NaCl were produced or we can use the<br />

ration of 1 mole of H2 to 2 moles of Na to convert to NaCl. This is known as the coefficient factor. The<br />

balanced equation makes it possible to convert information about one reactant or product to<br />

quantitative data about another element. Understanding this is essential to solving stoichiometric<br />

problems.<br />

Example 1<br />

Lead (IV) hydroxide and sulfuric acid react as shown below. Balance the reaction.<br />

Solution<br />

___Pb(OH)4 +___H2SO4→___Pb(SO4)2 +___H2O<br />

Start by counting the number of atoms of each element.<br />

Unbalanced<br />

Pb 1 1 Pb<br />

O 8 9 O<br />

H 6 2 H<br />

S 1 2 S<br />

The reaction is not balanced; the reaction has 16 reactant atoms and only 14 product atoms and does<br />

not obey the conservation of mass principle. Stoichiometric coefficients must be added to make the<br />

equation balanced. In this example, there are only one sulfur atom present on the reactant side, so a<br />

coefficient of 2 should be added in front of H2SO4to have an equal number of sulfur on both sides of<br />

the equation. Since there are 12 oxygen on the reactant side and only 9 on the product side, a 4<br />

coefficient should be added in front of H2O where there is a deficiency of oxygen. Count the number<br />

of elements now present on either side of the equation. Since the numbers are the same, the<br />

equation is now balanced.<br />

Pb(OH)4 + 2H2SO4→ Pb(SO4)2 + 4H2O<br />

Balanced<br />

Pb 1 1 Pb<br />

O 8 12 12 9 O<br />

H 6 8 8 2 H<br />

S 1 2 2 2 S<br />

Balancing reactions involves finding least common multiples between numbers of elements present<br />

on both sides of the equation. In general, when applying coefficients, add coefficients to the<br />

molecules or unpaired elements last.<br />

A balanced equation ultimately has to satisfy two conditions.<br />

1. The numbers of each element on the left and right side of the equation must be equal.<br />

2. The charge on both sides of the equation must be equal. It is especially important to pay<br />

attention to charge when balancing redox reactions.<br />

107


Stoichiometry and Balanced Equations<br />

In stoichiometry, balanced equations make it possible to compare different elements through the<br />

stoichiometric factor discussed earlier. This is the mole ratio between two factors in a chemical<br />

reaction found through the ratio of stoichiometric coefficients. Here is a real world example to show<br />

how stoichiometric factors are useful.<br />

Example 2<br />

There are 12 party invitations and 20 stamps. Each party invitation needs 2 stamps to be sent. How<br />

many party invitations can be sent?<br />

Solution<br />

The equation for this can be written as<br />

I+2S→IS2<br />

where<br />

I represent invitations,<br />

S represents stamps, and<br />

IS 2 represents the sent party invitations consisting of one invitation and two stamps.<br />

<br />

Based on this, we have the ratio of 2 stamps for 1 sent invite, based on the balanced equation.<br />

Invitations Stamps Party Invitations Sent<br />

In this example are all the reactants (stamps and invitations) used up? No, and this is normally the<br />

case with chemical reactions. There is often excess of one of the reactants. The limiting reagent, the<br />

one that runs out first, prevents the reaction from continuing and determines the maximum amount of<br />

product that can be formed.<br />

Example 3<br />

What is the limiting reagent in this example?<br />

Solution<br />

Stamps, because there was only enough to send out invitations, whereas there were enough<br />

invitations for 12 complete party invitations. Aside from just looking at the problem, the problem can<br />

be solved using stoichiometric factors.<br />

12 I x 1IS2 = 12 IS2 possible<br />

1I<br />

20 S x 1IS2 = 10 IS2 possible<br />

2S<br />

108


When there is no limiting reagent because the ratio of all the reactants caused them to run out at the<br />

same time, it is known as stoichiometric proportions.<br />

Types of Reactions<br />

There are 6 basic types of reactions.<br />

Combustion: Combustion is the formation of CO2 and H2O from the reaction of a chemical<br />

and O2<br />

Combination (synthesis): Combination is the addition of 2 or more simple reactants to form a<br />

complex product.<br />

Decomposition: Decomposition is when complex reactants are broken down into simpler<br />

products.<br />

Single Displacement: Single displacement is when an element from on reactant switches with<br />

an element of the other to form two new reactants.<br />

Double Displacement: Double displacement is when two elements from on reactants<br />

switched with two elements of the other to form two new reactants.<br />

Acid-Base: Acid- base reactions are when two reactants form salts and water.<br />

Molar Mass<br />

Before applying stoichiometric factors to chemical equations, you need to understand molar mass.<br />

Molar mass is a useful chemical ratio between mass and moles. The atomic mass of each individual<br />

element as listed in the periodic table established this relationship for atoms or ions. For compounds<br />

or molecules, you have to take the sum of the atomic mass times the number of each atom in order to<br />

determine the molar mass.<br />

Example 4<br />

What is the molar mass of H2O?<br />

Solution<br />

Molar mass = 2 × (1.00g/mol) + 1×(16.0g/mol) = 18.0g/mol<br />

Using molar mass and coefficient factors, it is possible to convert mass of reactants to mass of<br />

products or vice versa.<br />

Example 5: Combustion of Propane<br />

Propane (C3H8) burns in this reaction:<br />

C3H8 + 5O2 → 4H2O + 3CO2<br />

If 200 g of propane is burned, how many g of H2Ois produced?<br />

Solution<br />

Steps to getting this answer: Since you cannot calculate from grams of reactant to grams of products<br />

you must convert from grams of C3H8 to moles of C3H8 then from moles of C3H8 to moles of H2O.<br />

Then convert from moles of H2O to grams of H2O.<br />

109


Step 1: 200g C3H8 is equal to 4.54 mol C3H8.<br />

Step 2: Since there is a ratio of 4:1 H2O to C3H8, for every 4.54 mol C3H8 there are 18.18 mol<br />

H2O.<br />

Step 3: Convert 18.18 mol H2O to g H2O 18.18 mol H2O is equal to 327.27 g H2O.<br />

Variation in Stoichiometric Equations<br />

Almost every quantitative relationship can be converted into a ratio that can be useful in data<br />

analysis.<br />

Density<br />

Density (ρ) is calculated as mass/volume. This ratio can be useful in determining the volume of a<br />

solution, given the mass or useful in finding the mass given the volume. In the latter case, the inverse<br />

relationship would be used.<br />

Volume x (Mass/Volume) = Mass<br />

Mass x (Volume/Mass) = Volume<br />

Percent Mass<br />

Percent establishes a relationship as well. A percent mass states how many grams of a mixture are of<br />

a certain element or molecule. The percent X% states that of every 100 grams of a mixture, X grams<br />

are of the stated element or compound. This is useful in determining mass of a desired substance in<br />

a molecule.<br />

Example 6<br />

A substance is 5% carbon by mass. If the total mass of the substance is 10.0 grams, what is the<br />

mass of carbon in the sample? How many moles of carbon are there?<br />

Solution<br />

10 g sample x 5 g carbon = 0.5 g carbon<br />

100 g sample<br />

0.5g carbon x 1 mol carbon = 0.0416 mol carbon<br />

12.0g carbon<br />

Molarity<br />

Molarity (moles/L) establishes a relationship between moles and liters. Given volume and molarity, it<br />

is possible to calculate mole or use moles and molarity to calculate volume. This is useful in chemical<br />

equations and dilutions.<br />

110


Example 7<br />

How much 5M stock solution is needed to prepare 100 mL of 2M solution?<br />

Solution<br />

100 mL of dilute solution (1 L/1000 mL) (2 mol/1L solution) (1 L stock solution/5 mol solution) (1000<br />

ml stock solution/1L stock solution) = 40 mL stock solution.<br />

These ratios of molarity, density, and mass percent are useful in complex examples ahead.<br />

Determining Empirical Formulas<br />

An empirical formula can be determined through chemical stoichiometry by determining which<br />

elements are present in the molecule and in what ratio. The ratio of elements is determined by<br />

comparing the number of moles of each element present.<br />

Example 8<br />

1. Find the molar mass of the empirical formula CH2O.<br />

12.0g C + (1.00g H) * (2H) + 16.0g O = 30.0 g/mol CH2O<br />

2. Determine the molecular mass experimentally. For our compound, it is 120.0 g/mol.<br />

3. Divide the experimentally determined molecular mass by the mass of the empirical formula.<br />

(120.0 g/mol) / (30.0 g/mol) = 3.9984<br />

4. Since 3.9984 is very close to four, it is possible to safely round up and assume that there was a<br />

slight error in the experimentally determined molecular mass. If the answer is not close to a whole<br />

number, there was either an error in the calculation of the empirical formula or a large error in the<br />

determination of the molecular mass.<br />

5. Multiply the ratio from step 4 by the subscripts of the empirical formula to get the molecular<br />

formula.<br />

CH2O * 4 =?<br />

C: 1 * 4 = 4<br />

H: 2 * 4 = 8<br />

O 1 * 4 = 4<br />

CH2O * 4 = C4H8O4<br />

6. Check your result by calculating the molar mass of the molecular formula and comparing it to the<br />

experimentally determined mass.<br />

molar mass of C4H8O4= 120.104 g/mol<br />

experimentally determined mass = 120.056 g/mol<br />

% error = | theoretical - experimental | / theoretical * 100%<br />

% error = | 120.104 g/mol - 120.056 g/mol | / 120.104 g/mol * 100%<br />

% error = 0.040 %<br />

111


Stoichiometry and balanced equations make it possible to use one piece of information to calculate<br />

another. There are countless ways stoichiometry can be used in chemistry and everyday life. Try and<br />

see if you can use what you learned to solve the following problems.<br />

Problem 1<br />

Why are the following equations not considered balanced?<br />

a. The The O is not balanced because it should be multiplied by 2 inorder to make it even,<br />

H2O(l)→H2(g)+O2(g)<br />

b. Zn(s)+Au + (aq) →Zn 2+ (aq) +Ag(s)<br />

here balanced because they are diffrent elements.<br />

Problem 2<br />

Hydrochloric acid reacts with a solid chunk of aluminum to produce hydrogen gas and aluminum ions.<br />

Write the balanced chemical equation for this reaction.<br />

HCl + Al = 3H2 +2 AlCl3<br />

Problem 3<br />

H 6 H 2 6<br />

Cl 6 Cl 3 6<br />

Al 2 Al 1 2<br />

Given a 10.1M stock solution, how many mL must be added to water to produce 200 mL of 5M<br />

solution?<br />

5ml<br />

10.1*1/1000* 5/1*1/10.1*1000/1= 5<br />

Problem 4<br />

If 0.502g of methane gas react with 0.27g of oxygen to produce carbon dioxide and water, what is the<br />

limiting reagent and how many moles of water are produced? The unbalanced equation is provided<br />

below.<br />

CH4(g)+O2(g)→CO2(g)+H2O(l)<br />

2 2<br />

C 1<br />

H 4<br />

O 2 4<br />

C 1<br />

H 2 4<br />

O 3 4<br />

Ch is the limiting reageant because the result is smaller<br />

the O2.<br />

.502 g 1 mol Ch 2 mol H2O 18g H2o<br />

16g CH 1mol Ch 1mol H2O= 10.072/16<br />

= 1.1295<br />

.27 g O2 1ml O2 2 mol H2O18 mol H2O<br />

32gO2 2 mol O2 1mol H2O<br />

= 174.96/68<br />

112<br />

2.73375


Theoretical and Actual Yields<br />

Key Terms<br />

<br />

<br />

<br />

(Excess reagent, limiting reagent)<br />

Theoretical and actual yields<br />

Percentage or actual yield<br />

Skills to Develop<br />

Use stoichiometric calculation to determine excess and limiting reagents in a chemical reaction<br />

<br />

<br />

and explain why.<br />

Calculate theoretical yields of products formed in reactions that involve limiting reagents.<br />

Evaluate percentage or actual yields from known amounts of reactants<br />

Theoretical and Actual Yields<br />

Reactants not completely used up are called excess reagents, and the reactant that completely<br />

reacts is called the limiting reagent. This concept has been illustrated for the reaction:<br />

2Na+Cl2 →2NaCl<br />

Amounts of products calculated from the complete reaction of the limiting reagent are called<br />

theoretical yields, whereas the amount actually produced of a product is the actual yield. The ratio of<br />

actual yield to theoretical yield expressed in percentage is called the percentage yield.<br />

percent yield = actual yield / theoretical yield ×100<br />

Chemical reaction equations give the ideal stoichiometric relationship among reactants and products.<br />

Thus, the theoretical yield can be calculated from reaction stoichiometry. For many chemical<br />

reactions, the actual yield is usually less than the theoretical yield, understandably due to loss in the<br />

process or inefficiency of the chemical reaction.<br />

Example 1<br />

Methyl alcohol can be produced in a high-pressure reaction<br />

CO(g) + 2H2(g) →CH3OH(l)<br />

If 6.1 metric tons of methyl alcohol is obtained from 1.2 metric tons of hydrogen reacting with excess<br />

amount of CO, estimate the theoretical and the percentage yield?<br />

Hint:<br />

To calculate the theoretical yield, consider the reaction<br />

CO(g) + 2H2(g) → CH3OH(l)<br />

28.0 + 4.0 = 32.0 (stoichiometric masses in, g, kg, or tons)<br />

1.2 tons H2 × 32.0 CH3OH = 9.6 tons CH3OH<br />

4.0 H2<br />

Thus, the theoretical yield from 1.2 metric tons (1.2x10 6 g) of hydrogen gas is 9.6 tons. The actual<br />

yield is stated in the problem, 6.1 metric tons. Thus, the percentage yield is<br />

%yield = 6.1 tons × 100 = 64%<br />

9.6tons<br />

113


Discussion<br />

Due to chemical equilibrium or the mass action law, the limiting reagent may not be completely<br />

consumed. Thus, a lower yield is expected in some cases. Losses during the recovery process of the<br />

product will cause an even lower actual yield.<br />

Example 2<br />

A solution containing silver ion, Ag + , has been treated with excess of chloride ions Cl − . When dried,<br />

0.1234 g of AgCl was recovered. Assuming the percentage yield to be 98.7%, how many grams of<br />

silver ions were present in the solution?<br />

Hint:<br />

The reaction and relative masses of reagents and product are:<br />

The calculation,<br />

Ag + (aq) + Cl − (aq) → AgCl(s)<br />

107.868 + 35.453 = 143.321<br />

0.1234 g AgCl ×107.868 g Ag + =0.09287 g Ag +<br />

143.321g AgCl<br />

shows that 0.1234 g dry AgCl comes from 0.09287g Ag + ions. Since the actual yield is only 98.7%,<br />

the actual amount of Ag + ions present is therefore<br />

0.09287 g Ag + = 0.09409 g Ag +<br />

0.987<br />

Discussion<br />

One can also calculate the theoretical yield of AgCl from the percentage yield of 98.7% to be<br />

0.1234 g AgCl =0.1250 g AgCl<br />

0.987<br />

From 0.1250 g AgCl, the amount of Ag + present is also 0.09409 g.<br />

Stoichiometry - A Review<br />

Skills Taught<br />

<br />

<br />

<br />

<br />

<br />

<br />

<br />

evaluate molecular weight for a given formula<br />

evaluate weight (mass) percentages of elements for a given formula<br />

evaluate amounts (in mass and mole units) produced in a chemical reaction from given<br />

conditions<br />

classify reactions by types: combination, combustion, displacement, formation, etc<br />

determine the chemical formula when weight percentages are given and then evaluate the<br />

mole percentages of elements in the formula<br />

determine the chemical formula when weight percentages are given and molecular weight is<br />

known<br />

determine the amount produced, the actual yield, and other stoichiometry quantities for a given<br />

reaction<br />

114


Review Purposes<br />

<br />

<br />

<br />

<br />

<br />

To get an overall view of stoichiometry.<br />

Apply skills learned to perform quantitative chemical analysis.<br />

Apply theories and rules of chemistry to solve problems.<br />

Assess areas of strength and weakness for review purposes.<br />

Improve problem solving strategy and learning efficiency.<br />

Stoichiometry<br />

STOICHIOMETRY is the quantitative relationship of reactants and products. This unit has been<br />

divided into the following objects. A brief review is given here so that you can get a birds'-eye or<br />

overall view of stoichiometry.<br />

1. Amounts of substances<br />

Express amounts of substance in mass units of g, kg, tons, and convert them to moles,<br />

kilomoles, or millimoles.<br />

2. Chemical formulas<br />

Represent a substance with a formula that reflects its chemical composition, structure, and<br />

bonding; evaluate weight and mole percentages of elements in a substance; and determine<br />

chemical formula by elemental analysis.<br />

3. Reaction features<br />

Define some common features of chemical reactions; classify chemical reactions by common<br />

features such as combination, combustion, decomposition, displacement, and redox reactions.<br />

4. Reaction equations<br />

Express quantitative relationships using chemical reaction equations; evaluate quantities of<br />

reactants and products in a chemical reaction; and solve reaction stoichiometry problems.<br />

5. Excess and limiting reagents<br />

Define excess and limiting reagents; determine excess and limiting reagents in a reaction<br />

mixture; and determine quantities produced in a chemical reaction.<br />

6. Yields<br />

Define theoretical and actual yields due to limiting reagent; apply the concept of limiting<br />

reagent to evaluate theoretical yield; convert actual yield to percentage yields.<br />

115


Stoichiometry<br />

Molecular mass- is a number equal to the sum of the atomic masses of the atoms in a molecule. The molecular mass gives the mass of a molecule relative to that of the 12C atom, which is taken to have a mass of<br />

12.<br />

Example 1: Find molecular mass of Na2S<br />

1.First you look at the periodic table identify were they are located then see what’s their atomic mass and see how many elements of each are there.<br />

2. lastly you multiply the number of each element there is and then add them and you get the molecular mass.<br />

Na 2*23= 46<br />

S 1* 32 = 32 = 78 g Na2S<br />

Example 2; FO3<br />

1.First you look at the periodic table identify were they are located then see what’s their atomic mass and see how many elements of each are there.<br />

2. lastly you multiply the number of each element there is and then add them and you get the molecular mass.<br />

F 1*19 = 19<br />

0 3* 16 = 48 = 67 g Fo3<br />

Mole to mole- is the conversion in which we are converting moles of an elements into another mole of another element.<br />

Example 1<br />

For the balanced equation shown below, how many moles of C2H3F3 will react with 0.6568 moles of H2O?<br />

4C2H3F3+11O2=>8CO2+6H2O+6F2<br />

1.First, you must identify the amount it will reaction be and with what element. And how many moles each element has. If it not balanced balance it.<br />

You are working with .6568 and C2H3F3 and H2O<br />

C2H3F3 = 4 Moles<br />

H2O = 6 moles<br />

2.Next you must set a up a conversion to Convert 0.6568 moles of H2O to moles of C2H3F3. You must do this by canceling each<br />

Other components they have like Moles and OR and element and you do this by diving them by each other to make them cancel out. You will use the fact that 4 moles of C2H3F3 equal to 6 moles of H2O .<br />

.6558 MoL H2O 4 Mol C2H3F3 = 2.6272 Mol C2H3F3<br />

6 MoL H2O = 6 = .43786667 Mol C2H3F2<br />

3.,6568 had four the final product must have 4. Number only. After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by<br />

the bottom and you will get your result, but you must put it in Significant figures because<br />

.43786667 Mol C2H3F2= .4378 Mol C2H3F2 This is the final answer because of significant figures.<br />

Example 2<br />

For the balanced equation shown below, how many moles of NO2 will react with 0.4817 moles of O2?<br />

2N2O5=>4NO2+O2<br />

1.First you must identify the reaction number and see how many moles each element has. If were not given a balanced equation we must balance it,<br />

0.4817 and 4 moles NO2 and 1 mole O2<br />

2.Next you must set a up a conversion to Convert 0.4817moles of O2 to moles of NO2. You must do this by canceling each other’s components they. You will use the fact that 1 mole of O2 equal to 4 moles of<br />

NO2.<br />

.4817 MoL O2 4 Mol NO2 = 1.9268 Mol NO2<br />

1 MoL O2 = 1 = 1.9268 Mol of No2<br />

3. You must multiply everything on the top and bottom by itself and lastly divide the top by the bottom.<br />

1.9268 Mol of No2= 1.928 Mol of No2 This is the final answer because of significant figures and round<br />

Mass to mass- is the conversion of grams of an element to moles of the same element than to another element than to grams of that last element Basically grams of and element to another Grans of another<br />

elements.<br />

Example 1<br />

For the balanced equation shown below, how many Grams of C2H3F3 will react with 0.6568 grams of H2O?<br />

4C2H3F3+11O2=>8CO2+6H2O+6F2<br />

1.You first must identify each element’s atomic mass that the problem tells you to do. You find the atomic mass by looking at the periodic table below the letter if it need to be rounded you round and multiply<br />

by the number of elements it each has the ones you must add all the products. And figure out what is equal to what. Identify how many moles each element has and the reaction .<br />

1mole of C2H3F3 = 84 g of C2H3F3<br />

C 2 * 12= 24 H 3 * 1= 3 F 3 * 19= 57 = 84 H 2* 1 O*16= 16 = 18 1mole of H2O = 18 g of H2O<br />

Reaction .06568<br />

6 moles of H2O = 4 moles of C2H3F3<br />

2. Next you must set a up a conversion to Convert 0.6568 grams of H2O to grams of C2H3F3. You must do this by canceling each Other<br />

components they have you first cancel grams then moles than you end with grams as the result. And use the highlighted key above to do it.<br />

.6568 g H2O 1 Mol H2O 4 Mol C2H3F3 84 g C2H3F3 = 220.6848 g C2H3F3<br />

18 g H2O 6 Mol H2O 1 Mol C2H3F3 = 108 = 2.04337778 g C2H3F3<br />

3. After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result, but you must put it<br />

in Significant figures .<br />

2.04337778 g C2H3F3= 2.0433 g C2H3F3 This is the final answer because of significant figures<br />

Example 2<br />

For the balanced equation shown below, how many grams of H2 will react with 43.5 grams of N2?<br />

3H2+N2=>2NH3<br />

1. You first must identify each element’s atomic mass that the problem tells you to do. You find the atomic mass by looking at the periodic table and multiply by the number of elements it each has the ones you<br />

must add all the products. Identify what equal to each other.<br />

H2*1= 2 = 2 N2*14= 28 1mole of H2= 2 grams of H2<br />

1 mole of N2= 28 g of N2<br />

3 moles of H2= 1 mole of N2<br />

2. Next you must set a up a conversion to Convert 43.5 grams of N2 to grams of H2 . You must do this by canceling each Other<br />

components they have you first cancel grams then moles than you end with grams as the result. And use the highlighted key above to do it.<br />

43 .5 grams N2 1 Mol N2 3 Mol H2 2 g H2 = 261 g H2<br />

28 g N2 1 Mol H2O 1 Mol H2 = 28 = 9.321428571 g H2<br />

3.After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result, but you must put it in<br />

Significant figures.<br />

9.321428571 g H2 = 9.32 g H2 answer because of significant figures<br />

116


STP-Standard Temperature And Pressure, 0 Degree Celsius, 101.3 Atm or 1 atmosphere, 1 mole of gas =22.4 L<br />

Volume to volume: It is the conversion in which we are converting Liter or any other volume to another volume. Liters of an elements into another liter another elements. We do This by starting with liters than to moles; next, mole<br />

of the same element before to moles of another element than mole to the same element and liters and the moles and liter cancel out and all you have to do is divide but for the last you use the 22.4 L because that is the formula because<br />

we are dealing with gases.<br />

Example 1:<br />

For the balanced equation shown below, How much O2 will there be produced if we Combust 3.86 L of Co2?<br />

Co(g) +O2 => 2Co2(g)<br />

1.You first must identify each element’s atomic mass in liters for gas that the problem tells you to do which is 22.4 because it will always be that because that is the formula. You must remember the Formula as shown above STP.<br />

Lastly, we figure out what is equal to what. Identify how many moles each element has and the reaction.<br />

1 mole O2= 2 moles CO2<br />

1 mole Co2= 22.4 Co2 L<br />

mole O2= 22.4 O2 L<br />

2.Next you must set a up a conversion to Convert 3.86 Liters of Co2 to Liters of O2. You must do this by canceling each Other components they have you first cancel Liters then moles than you end with Liters as the result. And use<br />

the highlighted key above to do it.<br />

3.86 L Co2 1 Mol Co2 1 Mol O2 22.4 L O2 = 86.464 L O2<br />

22.4 22.4 L Co2 1 Mol Co2 1 Mol O2 = 44.8 = 1.93 L O2<br />

3.After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result, but you must put it in Significant figures.<br />

In this example its already in significant figures so we don’t change anything.<br />

2 1.93 L O2<br />

Example 2:<br />

For the balanced equation shown below, assume if we combust 1.3 L of Propane. How much Co2 will be produced?<br />

C3H8 + 5 O2 => 3 Co2+ 4H2O<br />

1.You first must identify each element’s atomic mass in liters for gas that the problem tells you to do which is 22.4 because it will always be that because that is the formula. You must remember the Formula as shown above STP.<br />

Lastly, we figure out what is equal to what. Identify how many moles each element has and the reaction.<br />

1 mole C3H8 = 3 mole Co2<br />

1 mole C3H8 = 22.4 L C3H8<br />

mole Co2 = 22.4 L Co2<br />

2.Next you must set a up a conversion to Convert 1.3 Liters of C3H8 to Liters of Co2. You must do this by canceling each Other components they have you first cancel Liters then moles than you end with Liters as the result. And use<br />

the highlighted key above to do it.<br />

1.3 L C3H8 1 Mol C3H8 3 Mol Co2 22.4 L Co2 = 87.36 L Co2<br />

22.4L C3H8 1 Mol C3H8 1 Mol Co2 = 22.4 = 3.9 L O2<br />

3.After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result, but you must put it in Significant figures.<br />

In this example its already in significant figures so we don’t change anything.<br />

3.9 L O2<br />

Limiting reagent: is the conversion of grams of an element to mole of the same element than to another element than to grams of that last element Basically grams of and element to another Grans of another elements. Its like mass to<br />

mass but a twist to it you have to do it twice because you are giving 2 different grams and then after you find the answer for both you choose the one with the smaller Number..<br />

Example 1: If 42.2g of C6H5F were reacted with 174g of O2, How many Grams of CO2woul be produced?<br />

1.You first must identify each element’s atomic mass. You find the atomic mass For both grams by looking at the periodic table and need to be rounded you round and multiply by the number of elements it each has the ones you<br />

must add all the products. And figure out what is equal to what. Identify how many moles each element. DO this twice for each gram.<br />

1 mole C6H5F = 96g C6H5F<br />

C6H5F+ 7O2-> 6 Co2<br />

1mole O2= 32g/mol<br />

C 6*12= 72 H5*1= 5 F1*19=19 = 96g/mol O2*16 = 32g/mol C1*12= 12 02*16= 32 = 44g/mol 1mole Co2 = 44g CO2<br />

1 mole C6H5F or 7 moles O2= 6 mole Co2<br />

2. Next you must set a up a conversion to convert 42.2g of C6H5F to CO2 grams of O2 . As well as convert 174g of O2 to grams of CO2. You must do this by canceling each Other<br />

components they have you first cancel grams then moles than you end with grams as the result. And use the highlighted key above to do it.<br />

42.2g C6H5F 1 mol C6H5F 6 mol CO2 44g CO2 = 11140.8<br />

96g C6H5F 1 mol C6H5F 1 mole CO2 = 96 = 116.50<br />

174 g o2 1 mol O2 6 mol CO2 44g CO2 = 45936<br />

32g O2 7 mol O2 1 mole CO2 = 224 = 205.07142<br />

3. After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result,Choos the one with lowest number and put<br />

in Significant figures.<br />

116 g Co2.<br />

Example 2: IF 5.43 Mg were reacted 27.8 g of H2SO4, how many grams of H2 are produced?<br />

1.You first must identify each element’s atomic mass. You find the atomic mass For both grams by looking at the periodic table and need to be rounded you round and multiply by the number of elements it each has the ones you<br />

must add all the products. And figure out what is equal to what. Identify how many moles each element. DO this twice for each gram.<br />

1 mole H2SO4= 98g H2SO4<br />

Mg+ H2SO4 -> MgSO4+H2<br />

1mole Mg= 24g Mg<br />

Mg 1*24 = 24 g/mol H2*1= 2g/mol H2*1= 2 S1* 32= 32 04*16= 64 = 98g/mol 1mole H2= 2g H2<br />

1 mole H2SO4 or 1 moles Mg= 1 H2<br />

2. Next you must set a up a conversion to convert 5.43g of Mg to grams of H2 . As well as convert 27.8 g of H2SO4 to grams of H2. You must do this by canceling each Other<br />

components they have you first cancel grams then moles than you end with grams as the result. And use the highlighted key above to do it.<br />

5.43g Mg 1 mol Mg 1 mol H2 2g H2 = 10.86<br />

24g Mg 1 mol Mg 1 mole H2 = 24 = .4525<br />

27.8 g H2SO4 1 mol H2SO4 1 mol H2 2g H2 = 55.6<br />

98g H2SO4 1 mol H2SO4 1 mole H2 = 98 = .56734694<br />

3.After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result, Choose the one with lowest number and<br />

put in Significant figures.<br />

.453 g H2<br />

Percent yield: You must Convert from a element to grams of another element like mass to mass but as well use part over whole, and percent equals actual over theoretician we are solving for theoretical.<br />

Example 1<br />

If the reaction of 27.0 g of O2 produced 59.1% yield how many grams of Co2 would be produced?<br />

C2H3Cl+2O2= =>2 Co2 +3HCl<br />

1.You first must identify each element’s atomic mass. You find the atomic mass by looking at the periodic table and need to be rounded you round and multiply by the number of elements it each has the ones you must add all the<br />

products. And figure out what is equal to what.<br />

1 mole O2= 32 g O2<br />

O2*16=32g C1*12= 12 02*16=32 = 44g<br />

1 mole Co2= 44g/mol Co2<br />

2 mole o2= 2 mole Co2<br />

2. Next you must set a up a conversion to convert 27.0g of O2 to grams of Co2 .. You must do this by canceling each Other<br />

components they have you first cancel grams then moles than you end with grams as the result. And use the highlighted key above to do it.<br />

27.0 g O2 1 mol O2 2 mol Co2 44g CO2 = 1376<br />

32g O2 2 mol O2 1 mole CO2 = 64 = 37.125<br />

3. After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result, The you use part over whole.<br />

37.125* .591= 21.940875 = 21.9 g CO2<br />

Example 2<br />

If the reaction of 48.3 g of Fe produced 41.4% yield how many grams of Fe3O4 would be produced? 3Fe+4H2O => Fe3O4 +4H2<br />

1.You first must identify each element’s atomic mass. You find the atomic mass by looking at the periodic table and need to be rounded you round and multiply by the number of elements it each has the ones you must add all the<br />

products. And figure out what is equal to what.<br />

1 mole Fe3O4 = 232 g Fe3O4<br />

Fe 1* 56= 56g Fe 3*56= 168 O 4*16=64 = 232g 1 mole Fe= 56 g Fe2<br />

3 mole Fe= 1 mole Fe3O4<br />

2. Next you must set a up a conversion to convert 27.0g of O2 to grams of Co2 .. You must do this by canceling each Other<br />

components they have you first cancel grams then moles than you end with grams as the result. And use the highlighted key above to do it.<br />

48.3g Fe 1 mol Fe 1 mol Fe3O4 232g Fe3O4 = 11205.6<br />

56g Fe 3 mol Fe 1 mole Fe3O4 = 168 = 66.7<br />

3. After you set up the Conversion you must multiply everything on the top by itself and everything in the bottom by itself and lastly divide the two by the bottom and you will get your result, The you use part over whole.<br />

66.7* .414= 27.6138 = 27.6 g Fe3O4<br />

117


Unit 6<br />

Chapter 13 States of Matter<br />

The students will learn what are the factors that determine and<br />

characteristics that distinguish gases liquids and solids and<br />

how substances change from one state to another.<br />

Differentiate among the four states of matter.<br />

Students will measure the physical characteristics of matter such as temperature<br />

and density.<br />

Students will compare and contrast the physical characteristics of the 4 states of<br />

matter.<br />

solid<br />

liquid<br />

gas<br />

plasma<br />

Relate temperature to the average molecular kinetic energy.<br />

Students will be able to compare and contrast the motion of particles of a sample<br />

at various temperatures.<br />

Kinetic energy<br />

Kinetic theory<br />

Temperature<br />

Describe phase transitions in terms of kinetic molecular theory.<br />

Students will be able to identify and describe phase changes.<br />

Students will be able to compare and contrast the change in particle motion<br />

for phase changes.<br />

Students will be able to interpret heating/cooling curves and phase diagrams.<br />

melting point<br />

freezing point<br />

boiling point<br />

condensation<br />

sublimation<br />

phase diagram<br />

kinetic molecular theory<br />

118


Chapter 14 The Behavior of Gases<br />

The students will learn how gases respond to changes in<br />

pressure, volume, and temperature and why the ideal gas law<br />

is useful even though ideal gases do not exist.<br />

Interpret the behavior of ideal gases in terms of kinetic molecular theory.<br />

Students will be able to describe the behavior of an ideal gas.<br />

Students will participate in activities to apply the Ideal Gas Law and its<br />

component laws to predict gas behavior.<br />

Students will be able to perform temperature/pressure conversions.<br />

Compressibility<br />

Boyle’s Law<br />

Charles’s Law<br />

Gay-Lussac’s Law<br />

Combine Gas Law<br />

Ideal Gas Law<br />

Partial pressure<br />

Dalton’s Law of partial pressure<br />

Diffusion<br />

Effusion<br />

Graham’s Law of effusion<br />

Chapter 15 Water and Aqueous Systems<br />

The students will learn how the interactions between water<br />

molecules account for the unique properties of water and how<br />

aqueous solutions form.<br />

Discuss the special properties of water that contribute to Earth's suitability<br />

as an environment for life: cohesive behavior, ability to moderate<br />

temperature, expansion upon freezing, and versatility as a solvent.<br />

Students will be able to prepare a solution of known molarity<br />

Students will participate in activities to calculate molarity<br />

Surface tension<br />

Surfactant<br />

Solvent<br />

Aqueous solution<br />

Solute<br />

119


Name: Emisael vega<br />

Name: Mayte Herrera<br />

Grade:<br />

States of Matter Project<br />

You and you lab partner are going to create a study aid in the form of a game for the<br />

information in Chapter 13 States of Matter.<br />

First, each of you, independently from each other, will summarize the chapter on 3<br />

pages of a pdf which will be submitted in Angel by the end of class on Monday Feb 26.<br />

Second, you and you lab partner will be given a game platform which you will use for<br />

your questions and answers, either Jeopardy or Kahoot.<br />

Third, you will fill in the information at the bottom of this page with your username,<br />

passwords and/or websites so that you do not forget this and I have a copy in case<br />

anything gets misplaced. This page will be submitted into Angel as a Word Document<br />

on Monday February 26 during class.<br />

Fourth, you will use your notes to generate the questions and answers.<br />

<strong>Final</strong>ly you will give me access to your game by putting the website or Game Number<br />

on this page adding this page to your 3 pages of notes and resubmitting it in Angel as<br />

a pdf by the end of the class on Wednesday Feb 28.<br />

This page is due by the end of class on Monday February 26.<br />

This Project is due by the end of class on Wednesday February 28.<br />

Jeopardy (https://jeopardylabs.com)<br />

Password:<br />

Edit Link:<br />

Play Link:<br />

Kahoot (https://getkahoot.com)<br />

Username: MayH0123<br />

Email: mayte.herrera.lwths@gmail.com<br />

Password: 011123mayh<br />

120


CORNELL NOTES<br />

Learning Goal:<br />

Differentiate<br />

Among the four states of matter.<br />

Questions/Main Ideas<br />

13.1 The nature of gases<br />

The nature of Gases<br />

Kinetic theory and a model for gases<br />

Name: __Emisael vega<br />

Class: __<strong>Chemistry</strong> Honors Topic: 13 States matter<br />

Date: _02______/ _23____/ __2018______<br />

Period _7_____<br />

NOTES<br />

Kinetic is motion. Kinetic theory states that all he matters consist of tiny particles that<br />

are in motion constantly. In gases the particles are relatively far apart and as well have<br />

no limit were to go<br />

What are the three assumptions of kinetic<br />

theory in gases?<br />

Gas pressure<br />

Explain how kinetic theory explains gas<br />

pressure?<br />

Conversing between Units of pressure.<br />

- Particles in gases are considered to be small, hard spheres with insignificant<br />

volumes<br />

- The particles motion in gas are rapid, constant and random. In general, all<br />

over the place<br />

- Collisions between particles are very elastic meaning very stretchable.<br />

Gas pressure results from the force exerted by a gas per unit surface are of an object.<br />

Vacuum in science is an empty space with no Particles.<br />

Atmospheric Pressure is the collision of atoms and molecules in the air with objects.<br />

Barometer is a device that is used to measure atmospheric Pressure.<br />

Kinetic theory explains gas pressure because it results in innumerable of fast moving<br />

particles in gas simultaneously colliding with an object.<br />

If no particles are present, no collision can occur because there is no available<br />

pressure.<br />

Pressure= 450 kPa<br />

The Si unit of pressure is pascal (pa) It represent a very small amount of pressure.<br />

Example: Normal Atmospheric pressure is about 100,000 Pa.<br />

1 atm = 101.3 kPa Standard atmosphere (atm) is the pressure required in order to support about 760 mm<br />

of mercury in mercury barometer at 25 degrees Celsius.<br />

1 Atm = 760 mm Hg<br />

Kinetic Energy and Temperature<br />

Average kinetic energy<br />

Average kinetic Energy and kelvin<br />

temperature<br />

The particles in any collection of atoms or molecule at given temperature have a wide<br />

range of kinetic energies. Most of those particles have kinetic energies somewhere in<br />

the middle of the range.<br />

Therefore, we use average kinetic energy when discussing the kinetic energy of<br />

collections of particles ion, a substance.<br />

The kelvin temperature shows the relationship between Temperature and average<br />

kinetic energy the kelvin temperature of a substance is directly equal/proportional to<br />

average kinetic energy of the particles in a substance.<br />

13.2 The Nature of Liquids Particles in gasses and the particles in liquid have kinetic energy. That energy allows<br />

the particle to go into gasses and liquids to flow past another which further allows to<br />

be the shape of the containers they are in,.<br />

What things Determine the physical<br />

properties of liquids?<br />

Evaporation<br />

What is the relationship between evaporation<br />

and kinetic energy?<br />

The interplay between the disruptive motions of particle in a liquid and attractions<br />

among particles determine the physical properties of liquids.<br />

Vaporization is the conversion of a liquid to gas or vapor. Evaporation is when the<br />

surface of a liquid is not boiling.<br />

In evaporation only, some molecules with certain minimum kinetic energy can escape<br />

from the surface of the liquid.<br />

Vapor Pressure Vapor pressure is the measure of the force exerted by a gas above a liquid. Liquid ><br />

Evaporation>vapor gas. Condensation>liquid<br />

In a system of repetitive vapor pressure, a dynamic equilibrium exists between the<br />

vapor and the liquid. This system is equilibrium because the rate of evaporation of a<br />

liquid equals the rate of condensation and vapor .<br />

Boiling point<br />

In what condition does boiling happen?<br />

The rate of evaporation of liquid from an open Container increase as the liquid is<br />

heated. The heating allows the liquid particle overcome the attractive forces making<br />

them liquid which makes them go fast and become another particle .<br />

Boiling occurs in conditions of a liquid being heated to a temperature at which the<br />

particles of liquid have enough kinetic energy in order to vaporize and the liquid<br />

begins to boil.<br />

121


Normal boiling point<br />

SUMMARY:<br />

Liquids do not always boil in at the same temperate due to the fact that some<br />

atmospheric pressures are lower at higher altitudes. All in all, boiling point differ<br />

because of higher altitudes.<br />

A liquid can have Various Boiling point de3pending on the pressure.<br />

Normal Boiling point is the boiling point of a liquids pressure of 101.3 kPa<br />

The nature of gases and nature of liquids.<br />

Particles in gasses are considered very small and the motion of gases are is fast consistent and unusual.<br />

Collision in gases are very flexible and elastic. Gas pressure result from the collision and is measured by a tool<br />

called barometer. Both gasses and liquids particles have kinetic energy allowing them to take a shape in a<br />

container or anything that is a shape. Compared to gasses liquids are much denser. When a liquid is heated, the<br />

liquid evaporates. There is certain boiling point for creation liquids because of altitude.<br />

Questions/Main Ideas NOTES<br />

13.3 The nature of solids The general properties of the solids reflect the orderly arrangement of their particles<br />

and the fixed location of their particles.<br />

A model for solids<br />

The melting points the temperature in which solids change into liquids.<br />

The freezing point is the temperature at which a liquid changes into solid.<br />

When a solid is heated the particles vibrate more rapidl7y as their kinetic energy<br />

increase.<br />

In general, ionic solids have high melting points because they have high relatively<br />

strong Forces that hold them intact. Like sodium chloride has melting point of 801<br />

Celsius<br />

Molecular solids have relatively low melting points. Example hydrogen chloride a<br />

molecular compound melts at -122<br />

Crystal structure And unit cells The thing that controls the shape of the crystal is the shape in which reflects the<br />

arrangement of the particles within the solid.<br />

Crystal systems<br />

A crystal has a side or faces. The angles at which the face of a crystal intersects are<br />

always the same as the given substance<br />

Crystals are classified into seven 7 groups or crystal system which are labeled a ,b,<br />

and c. The seven groups differ in terms of the angles between the faces and in their<br />

number<br />

Unit cells are the smallest groups of particles within a crystal that retain the geometric<br />

shape of the crystal.<br />

Allotropes<br />

Some other types of solid substance can live in more than one form. Like carbon.<br />

Simple cubic- Is a simple cubic unit cell that toms are arranged at the corners of an<br />

imaginary cube.<br />

Body centered cubic unit cells of the atom or ions are at the corners and in the center<br />

of an imaginary cube.<br />

Face centered is the cubic unit cell where the atoms or ions at the corners and in the<br />

center of each face of the imaginary cube.<br />

The physicals properties of diamond, graphite and fullerene are quite different.<br />

Diamond has high density and is hard. Graphite has relatively low density and is the<br />

soft and slippery.<br />

The hollow cages of fullerenes give them great strength and rigidly. But all of them<br />

are Crystalline allotropes of carbons.<br />

Allotropes are two or more different molecular forms of the same element in the same<br />

physical state.<br />

Although they are composed of atoms of the same element they have different<br />

properties because they have all different structures<br />

Non crystalline solids Not all solids are crystalline in form some solids are amorous<br />

Amorphous solids lack an ordered internal structure meaning that rubber, plastic, and<br />

asphalt are amorphous solids.<br />

122


Questions/Main Ideas NOTES<br />

13.4 changes of states The change of a substance is from a solid to vapor without passing through the<br />

liquid states is called sublimation<br />

Sublimation<br />

Sublimation can happen when because solids like liquids have a vapor pressure<br />

Sublimation occurs in solid vapors pressures that exceeds atmospheric pressure<br />

at or near room temperature. Iodine is an example that goes through<br />

sublimation.<br />

When solid iodine is heated the crystals sublime going directly from solid to<br />

gaseous state. When it cools, it goes directly from gas to liquid.<br />

Sublimation Has many useful thing such as brewed coffee.<br />

Organic chemist use dry ice to separate mixtures and to purify compounds.<br />

Phase diagrams<br />

They give conditions of temperature and pressure at which as substance exist as<br />

solids liquids and gasses.<br />

The conditions of pressure and the temperature at which two phases exist in<br />

equilibrium are indicated on phase diagrams by a line separating the rwo regions<br />

representing the phases.<br />

The triple point describes the only set condition at which all three phases can<br />

exist in equilibrium with one another.<br />

When an amorphous solid such as glass is shattered the fragments have irregular<br />

angles and jagged edges<br />

Glasses are sometimes called supercool liquids.<br />

A glass is a transparent fusion product of inorganic substances.<br />

You can determine what happens if you melt ice or boil, water at pressure less<br />

than 101.3kPa A decrees in temperature lowers the boiling point. Moreover,<br />

raises the melting point.<br />

With an increase in pressure, it will not change the vapor to a liquid.<br />

The solid and the vapor are in equilibrium at temperature below 0.016 Celsius..<br />

A plasma is gaseous mixture of freely moving positive ions and electrons.<br />

It exist naturally in the sun and other stars and in lighting. Plasmas can be<br />

artificially created and used in a variety of technologies.<br />

Plasma waste convers have many benefits overall traditional waste treatment<br />

They do not require the use of dumps or landfills and they emit much less<br />

greenhouse gases and other pollutants than incinerators.<br />

Plasma furnace the plasma torches turn trash into syngas and slag. The<br />

composition of the trash determines and the product.<br />

SUMMARY:<br />

Overall, Sublimation occurs in solid vapors pressures that exceeds atmospheric pressure at or near room<br />

temperature. Iodine is an example that goes through sublimation. The change of a substance is from a solid<br />

to vapor without passing through the liquid states is called sublimation. The phase diagrams they give<br />

conditions of temperature and pressure at which as substance exist as solids liquids and gasses.<br />

123


The Learning Goal for this is: Students will be able to perform temperature /preszsure conversions and volume<br />

The students will learn how balanced chemical equations are used in stoichiometric calculations and how to calculate<br />

amounts of reactants and products in a chemical equation.<br />

Introduction to Gases<br />

Gas Laws<br />

Of the three common states of matter, the gaseous state was most easily described by early<br />

scientists. As early as 1662, Robert Boyle showed how the volume of a gas, any gas, changed as the<br />

pressure applied to it was changed. Soon thereafter, the effects of temperature and the quantity of<br />

gas on the volume were discovered. The result of all these studies was a set of fundamental<br />

mathematical equations known as the gas laws that applied equally well to any gas, whether pure<br />

oxygen, nitrogen, or a mixture of the two. Through careful studies of gases reacting with one another,<br />

Amedeo Avogadro later concluded that equal volumes of different gases must contain the same<br />

number of molecules. For example, 10.0 L of oxygen contained the same number of oxygen<br />

molecules as there were nitrogen molecules in 10.0 L of nitrogen.<br />

As time passed, it became clear that one mole of any gas contained the same number of molecules,<br />

6.02 × 10 23 molecules to be exact, a number known today as Avogadro's number. One mole of<br />

anything is Avogadro's number of that thing—atoms, molecules, people, or dollars—and that would<br />

be a lot of dollars!<br />

Boyle's Law<br />

Pressure is the amount of force exerted on one unit of area. The example of an ocean diver should<br />

make the concept clearer: The greater the depth the diver reaches, the greater the pressure due to<br />

the weight of the overlying water. Pressure is not unique to liquids but can be transmitted by gases<br />

and solids, too. At the surface of the Earth, the weight of the overlying air exerts a pressure equal to<br />

that generated by a column of mercury 760 mm high. The two most common units of pressure in<br />

chemical studies are atmosphere and millimeters of mercury.<br />

1 atm = 760 mm Hg = 760 torr.<br />

However, the standard international unit for pressure is the Pascal.<br />

1 atm = 101325 Pa<br />

1 atm = 101.3 kPa<br />

The English scientist Robert Boyle performed a series of experiments involving pressure and, in<br />

1662, arrived at a general law—that the volume of a gas varies inversely with pressure.<br />

P1V1 = P2V2<br />

This formulation has become established as Boyle's law. Of course, the relationship is valid only if the<br />

temperature remains constant.<br />

As an example of the use of this law, consider an elastic balloon holding 5 L of air at the normal<br />

atmospheric pressure of 760 mm Hg. If an approaching storm causes the pressure to fall to 735 mm<br />

Hg, the balloon expands. The product of the initial pressure and volume is equal to the product of the<br />

final pressure and volume while the temperature is constant.<br />

124


It is important that you realize that pressure and volume vary inversely; therefore, an increase in<br />

either one necessitates a proportional decrease in the other.<br />

Convert a pressure of 611 mm Hg to atmospheres.<br />

.794Atm<br />

1. If a gas at 1.13 atm pressure occupies 732 milliliters, what pressure is needed to reduce the<br />

volume to 500 milliliters?<br />

(1.13) 732 = n (500)<br />

827.16 = 500p<br />

2 atm<br />

1.65432= P<br />

2=p<br />

Charles' Law<br />

In 1787, the French inventor Jacques Charles, while investigating the inflation of his man‐carrying<br />

hydrogen balloon, discovered that the volume of a gas varied directly with temperature. This relation<br />

can be written as<br />

V1 = V2<br />

and is called Charles' law. For this law to be valid, the pressure must be held constant, and the<br />

temperature must be expressed on the absolute temperature or Kelvin scale.<br />

T1<br />

Because the volume of a gas decreases with falling temperature, scientists realized that a natural<br />

zero‐point for temperature could be defined as the temperature at which the volume of a gas<br />

theoretically becomes zero. At a temperature of absolute zero, the volume of an ideal gas would be<br />

zero. The absolute temperature scale was devised by the English physicist Kelvin, so temperatures<br />

on this scale are called Kelvin (K) temperatures. The relationship of the Kelvin scale to the common<br />

Celsius scale must be memorized by every chemistry student:<br />

T2<br />

K = °C + 273<br />

Therefore, at normal pressure, water freezes at 273 K (0°C), which is called the freezing point, and<br />

boils at 373 K (100°C). Room temperature is approximately 293 K (20°C). Both temperature scales<br />

are used in tables of chemical values, and many simple errors arise from not noticing which scale is<br />

presented.<br />

Use Charles' law to calculate the final volume of a gas that occupies 400 ml at 20°C and is<br />

subsequently heated to 300°C. Begin by converting both temperatures to the absolute scale:<br />

T1 = 20°C = 293.15 K<br />

T2 = 300°C = 573.15 K<br />

125


Then substitute them into the constant ratio of Charles' law:<br />

When using Charles' law, remember that volume and Kelvin temperature vary directly; therefore, an<br />

increase in either requires a proportional increase in the other.<br />

2. A gas occupying 660 ml at a laboratory temperature of 20°C was refrigerated until it shrank to 125<br />

ml. What is the temperature in degrees Celsius of the chilled gas?<br />

660/20c = 125ml/t<br />

+273<br />

660ml/293 = 125/t<br />

Gay-Lussac's Law<br />

36625=660t<br />

t=55.4924<br />

-273<br />

t=218.494<br />

p =200c<br />

-200 C<br />

This relationship between temperature and pressure is known as Gay-Lussac's law. It states that if<br />

the volume of a container is held constant as the temperature of a gas increases, the pressure inside<br />

the container will also increase. As with the other gas laws, this one can be represented in the form of<br />

an equation:<br />

P1 = P2<br />

T2<br />

Recall that we use 1s and 2s to indicate the quantities before (1s) and after (2s) a change has taken<br />

place. Also, note that the units for pressure do not matter, as long as they are the same throughout<br />

the entire equation. The units for temperature must be Kelvins or the equation will not work. This is<br />

because the Kelvin scale is an absolute scale - it doesn't go negative. <strong>Final</strong>ly, this equation only<br />

works for an ideal gas. Most gases that surround you and me behave very much like ideal gases, so<br />

we can use this equation as an approximation for the gases we encounter.<br />

T2<br />

126


127<br />

3. The pressure of nitrogen gas in a light bulb is 60 kPa at 25°C. Calculate the pressure of the gas<br />

when the temperature inside the bulb rises to 167°C after the bulb is lighted up?<br />

60/25=p/167<br />

+273 +273<br />

60/298=p/440<br />

Combined gas law<br />

298=269400<br />

p=88.590604013<br />

p=90<br />

90 Kpa<br />

The combined gas law makes use of the relationships shared by pressure, volume, and temperature:<br />

the variables found in other gas laws, such as Boyle's law, Charles' law and Gay-Lussac's law. Let's<br />

review the basic principles of these three laws.<br />

Imagine you are a diver, and you begin your dive with lungs full of air. As<br />

you go deeper under water, the pressure you experience in your lungs<br />

increases. When this happens, the air inside your lungs gets squished, so<br />

the volume decreases. This is an example of Boyle's law in action, which<br />

states that the higher the pressure (P), the lower the volume (V), as<br />

shown in this image. Here, k is any constant number.<br />

Have you ever tried putting a balloon in the refrigerator and notice that it<br />

shrinks? As the temperature of the refrigerated balloon decreases, the<br />

volume of the gas inside the balloon also decreases. When you take the<br />

balloon out of the refrigerator, it reverts to its original size, so the opposite is<br />

also true; when the temperature increases, the volume also increases. The<br />

shrinking balloon serves as a demonstration of Charles' law, which states<br />

that the higher the temperature (T), the higher the volume (V).<br />

Imagine yourself driving down a road, which can cause the<br />

temperature to increase within your tires. As a result, the air inside the<br />

tires expands, and the pressure increases. This is an example of Gay-<br />

Lussac's law, which shows the relationship between pressure (P) and<br />

temperature (T) when the volume remains constant; as the<br />

temperature increases, the pressure also increases.<br />

When we put Boyle's law, Charles' law, and Gay-Lussac's law together, we come up with the<br />

combined gas law, which shows that:<br />

<br />

<br />

<br />

Pressure is inversely proportional to volume, or higher volume equals lower pressure.<br />

Pressure is directly proportional to temperature, or higher temperature equals higher pressure.<br />

Volume is directly proportional to temperature, or higher temperature equals higher volume.<br />

Let's take a look at the formula for the combined gas law. Here, PV / T = k shows how pressure,<br />

volume and temperature relate to each other, where k is a constant number.<br />

The formula for the combined gas law can be adjusted to compare two sets of conditions in one<br />

substance. In the equation, the figures for pressure (P), volume (V), and temperature (T) with<br />

subscripts of one represent the initial condition, and those with the subscripts of two represent the<br />

final condition.


P1V1 = P2V2<br />

T1<br />

T2<br />

It is important to note that the temperature should always be in Kelvin, so if the given units are in<br />

Celsius, then those should be converted to Kelvin by adding 273.<br />

450 mL of a gas occupies a container that has a temperature of 28°C and a pressure of 788 mmHg.<br />

What is the temperature if the volume is reduced to 50 mL at 760 mmHg? As the unit of<br />

measurement is in Celsius, remember to convert it to Kelvin.<br />

4. A closed gas system initially has pressure and temperature of 1160torr and 542K with the volume<br />

unknown. If the same closed system has values of 912torr, 9720mL and 686K, what was the initial<br />

volume in L?<br />

1160 (v) = 9.720 (912)<br />

542k 686k 795760v= 4804634.88<br />

6.04 L<br />

v=6.03779390<br />

Ideal Gas Equation<br />

v=6.04<br />

The relations known as Boyle's law, Charles' law, and Avogadro's law can be combined into an<br />

exceedingly useful formula called the Ideal Gas Equation,<br />

where R denotes the gas constant:<br />

PV = nRT<br />

The temperature is, as always in gas equations, measured in Kelvin.<br />

128


This formula is strictly valid only for ideal gases—those in which the molecules are far enough apart<br />

so that intermolecular forces can be neglected. At high pressures, such forces cause significant<br />

departure from the Ideal Gas Equation, and more complicated equations have been devised to treat<br />

such cases. The Ideal Gas Equation, however, gives useful results for most gases at pressures less<br />

than 100 atmospheres.<br />

This is the value stated in the carbon dioxide reaction; you were asked to memorize that 1 mole of<br />

any gas occupies 22.4 liters at STP.<br />

You should be able to use the Ideal Gas Equation to determine any one of the four quantities—<br />

pressure, volume, moles, or temperature—if you are given values for the other three.<br />

One important application is to deduce the molecular mass and formula for a gas. Assume that you<br />

know that the hydrocarbon propylene is, by mass, 85.6% carbon and 14.4% hydrogen. Then the<br />

atomic ratios of the compound are<br />

Therefore, the propylene molecule is some integral multiple of CH2: It can be CH2 or C2H4 or C3H6 or<br />

a yet larger molecule. Measuring the volume of 10 grams of propylene at STP yields 5.322 liters,<br />

which you can use to calculate its molecular mass.<br />

Because the atomic masses of 1 CH2 unit added together is 14.03, the molecule contains three such<br />

units. Consequently, the molecular formula for propylene is C3H6.<br />

5. What is the volume occupied by 1 kilogram of carbon monoxide at 700°C and 0.1 atm?<br />

1kg=1000g 1000/28= 35.7142857 v0.1=2859.75/.1<br />

3,000<br />

c1*12=12<br />

o1 *16=16 =28 v0.1 =35*0.008218*973 v=3,000<br />

6. The ozone molecule contains only oxygen atoms. Determine the molecular formula of ozone given<br />

that 2.3 grams occupies 1,073 milliliters at standard temperature and pressure.<br />

1.0 atm<br />

2.3/48= 0.04791667<br />

No it doesnt because they are not equal to<br />

each other.<br />

03*16= 48<br />

1.073 * 1 atm =0.04791667*.00821*273<br />

1.073<br />

=<br />

.10739707<br />

129


The Learning Goal for this assignment is; Student will learn how the interactions<br />

between water molecules account for the unique properties of water and how solutions<br />

form.<br />

Take note over the following chapter. Use the Headings provided to organize your notes. Define and number all highlighted vocabulary (total 22 ) as well<br />

as summarize and take notes over the sections. You may add pictures where needed. The pictures should be an appropriate size. Use Arial 12 for all<br />

text. This document should be 2 pages and should be saved as a pdf before you submit it into Angel.<br />

Chapter 15 Water and Aqueous Systems<br />

Pages 488 - 507<br />

15.1 Water and Its Properties<br />

Water in the Liquid State<br />

Water is something vital to all human being and animals. Many unique and important properties of<br />

water including its high surface tension, low vapor pressure, and high boiling point results from<br />

bonding hydrogen. Water molecules at the surface tend to be drawn inward. The inward force or pull<br />

that tends to minimize the surface area of a liquid is called surface tension 1 . All liquids have surface<br />

tension, but water's surface tension is higher than most. A surfacant 2 is any substance that<br />

interferes with the hydrogen bonding between water molecules and for that reason reduces the<br />

surface tension in it,<br />

Water in the Solid State<br />

Solids are denser than liquids and liquids are denser than gases. When water is in its solid state, the<br />

water molecules are packed close together preventing it from changing shape. Ice has a very regular<br />

pattern with the molecules rigidly apart from one another connected through the hydrogen bonds that<br />

form a crystalline. These crystals have a number of open regions which allow the ice to float. The<br />

structure of ice is a regular open frame work of water molecules in hexanal arrangement. Hydrogen<br />

bonding is the result of ice cream.<br />

15.2 Homogeneous Aqueous Systems<br />

Solutions<br />

An aqueous 3 solution is the water that contains dissolved molecules of water including its high<br />

tension. In solution the dissolving medium is the solvent 4 . While the dissolved parts of the solution<br />

are called the solute 5 . Solvent and solutes can be identified as a gasses, liquids, or solids. While<br />

solutions are homogenous mixtures meaning any combination of substances that has uniform<br />

composition and properties. Substance that dissolve in water mostly consist of ionic compounds and<br />

polar covalent compounds. Water molecules are always in continuous movement due to the fact that<br />

they have kinetic energy. And there are different types of process such as solvation 6 which is the<br />

process in which the positive and negative of an ionic solid get surrounded by solvent molecules.<br />

While in other ionic compounds some attractions among the ions in crystal are stronger than the ones<br />

exerted by water. These compounds are insoluble meaning that they are unable to be dissolved.<br />

Electrolytes and Nonelectrolytes<br />

Electrolytes 7 is a compound which produces/conducts an electric current when its aqueous solution<br />

or when it is in a molten state. All ionic compounds are electrolytes due to the fact that they are<br />

unlatching. Basically they are Dispersing/ dispersing into ions. Nonelectrolyte 8 is a compound that<br />

does not conduct/ produce an electric current in either an aqueous solution or the molten state.<br />

While the nonelectrolytes are not electrolyte because they don’t contain ions. But some polar<br />

compounds are nonelectrolytes in a pure state which further become electrolytes when they are<br />

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dissolved in water. All electrolytes conduct an electric charge at different degrees. They are different<br />

types of electrolytes such as weak and strong. Strong electrolytes 9 are solutions which are nearly all<br />

of the solutes exist as ions. ON the other hand Weak electrolytes 10 conduct a very poor electric<br />

current due to the fact there is only a fraction of the solute in the solution which exist ions. Most<br />

important they are vital to metabolic process which are used to carry electrical impulses internally to<br />

other cells. Which are crucial to the nerves and the function of the muscles,<br />

Hydrates<br />

The water in which a crystal is contained in is referred to as a water of hydration 11 or water of<br />

crystallization. Different types of compounds have /contain water hydration in which is a hydrate 12 . As<br />

I stated before the crystal, is referred to as water of hydration it can be heated above 100 Celsius in<br />

which they lose their water of hydration. Furthermore the forces that are keeping the water molecules<br />

intact in hydrates aren’t very strong, so the water is easily lost or regained. Some hydrates contain<br />

water but some don’t. For example the substance anhydrous 13 does not contain water. There is<br />

different types of hydrates such as Efflorescent and hygroscopic Hydrates. Efflorescent hydrates is<br />

when the water molecules in hydrate are held by weak forces so the hydrates often have a good<br />

amount of vapor pressure. If it has a vapor pressure higher than the pressure of water vapor the<br />

hydrate will lose its water of hydration of effloresce 14 . While Hygroscopic hydrates have a low vapor<br />

pressure where the water is removed from the air to create a higher hydrate. The hydrates and the<br />

other compound which remove moisture from the air are referred to as hygroscopic 15 . An example of<br />

this would be calcium chloride which absorbs a second, molecule of water. It is also used a<br />

desiccant 16 which is a substance used to absorb moisture from the air and create a dry atmosphere.<br />

Similar to this would be a deliquescent 17 which means that they remo0ve sufficient water from the air<br />

to dissolve completely and form a solution,<br />

15.3 Heterogeneous Aqueous Systems<br />

Suspensions<br />

Heterogeneous mixtures are not solutions. For example a suspension 18 is a mixture from which<br />

particles settle out upon standing. Suspension are different from a solution because the particles of a<br />

suspensions are much large and don not stay suspended indefinitely. Particles have an average<br />

diameter greater that then 1000 nm. Suspension are heterogeneous due to the ACT that 2 substance<br />

can clearly be identified. Gelatin is an example of a mixture called a colloid.<br />

Colloids<br />

A colloid 19 is a heterogeneous mixture containing particles that range in size from 1nm to 1000 nm.<br />

The particles spread or disperse. Many colloids are cloudy and milky in appearance similar to<br />

suspension when they are concentrated. They can also look clear or almost clear like solutions when<br />

they are dilute. The important difference between colloids and solutions and suspensions is in the<br />

size of the particles. Colloids have particles smaller than the ones in suspension and larger than<br />

those in solution. Colloids have different things they cause such as effects, put things in motion. The<br />

tidal effect is one of these ordinarily you cannot see a beam of sunlight unless they pass through<br />

particles of water or dust sand sir. The reason why it’s visible is because they scatter the sunlight.<br />

The scattering of the visible light by colloidal particles is called the Tyndall effect 20 . While some are<br />

seen by sunlight other thing get studied in different ways. Such as flashes of lights or scintillations are<br />

seen when colloid are studied in microscopes. The chaotic movement of the colloids is which was first<br />

studied by brown a botanist which was later named Brownian motion 21 . Mayonnaise is an example<br />

of a colloidal system called an emulsion, an emulsion 22 is a colloidal dispersion of a liquid in a liquid.<br />

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Unit 7<br />

Chapter 16 Solutions<br />

The students will learn what properties are used to describe<br />

the nature of solutions and how to quantify the concentration<br />

of a solution.<br />

Chapter 17 Thermochemistry<br />

The student will learn how energy is converted in a chemical<br />

or physical process and how to determine the amount of<br />

energy is absorbed or released in that process.<br />

Differentiate among the various forms of energy and recognize that they can<br />

be transformed from one form to others.<br />

Students will participate in activities to investigate and describe the<br />

transformation of energy from one form to another (i.e. batteries, food, fuels,<br />

etc.)<br />

Explore the Law of Conservation of Energy by differentiating among open,<br />

closed, and isolated systems and explain that the total energy in an isolated<br />

system is a conserved quantity.<br />

Students will be able to calculate various energy changes:<br />

o q = mc∆t<br />

o ∆Hfus<br />

o ∆Hmelt<br />

Thermochemistry<br />

Heat<br />

System<br />

Surrounding<br />

Law of conservation of energy<br />

Bond Making is exothermic<br />

Bond Breaking is endothermic<br />

Heat capacity<br />

Specific heat<br />

Calorimetry<br />

Enthalpy<br />

Thermochemical equation<br />

Molar heat of (fusion, solidification,<br />

vaporization, condensation, solution)<br />

Distinguish between endothermic and exothermic chemical processes.<br />

Students will be able to recognize exothermic and endothermic reactions through<br />

experimentation.<br />

Students will participate in activities (Pasco) to create exothermic and<br />

endothermic graphs.<br />

Endothermic<br />

Exothermic<br />

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Create and interpret potential energy diagrams, for example: chemical<br />

reactions, orbits around a central body, motion of a pendulum<br />

Students will participate in activities (Pasco) to create exothermic and<br />

endothermic graphs.<br />

Students will be able to interpret exothermic and endothermic reaction graphs.<br />

Potential energy diagram<br />

Thermochemical equations<br />

Chapter 18 Reaction Rates and Equilibrium<br />

The student will learn how the rate of a chemical reaction can<br />

be controlled, what the role of energy is and why some<br />

reactions occur naturally and others do not.<br />

Explain how various factors, such as concentration, temperature, and<br />

presence of a catalyst affect the rate of a chemical reaction.<br />

Students will be able to describe how each factor may affect the rate of a<br />

chemical reaction.<br />

Students will be able to compare the relative effect of each factor on the rate of a<br />

chemical reaction.<br />

Rate<br />

Collision theory<br />

Activation energy<br />

Catalyst<br />

Activated complex<br />

Inhibitor<br />

Explain the concept of dynamic equilibrium in terms of reversible processes<br />

occurring at the same rates.<br />

Students will be able to describe a system in dynamic equilibrium.<br />

Students will be able to describe how factors may affect the equilibrium of a<br />

reaction.<br />

Reversible reaction<br />

Chemical equilibrium<br />

Le Chatelier principle<br />

Explain entropy’s role in determining the efficiency of processes that convert<br />

energy to work.<br />

Students will be able to describe the change in entropy of a reaction.<br />

Students will be able to determine if a reaction is spontaneous<br />

Entropy<br />

Law of disorder<br />

Spontaneous/nonspontaneous reaction<br />

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The Learning Goal for this assignment is:<br />

The students will learn what properties are used to describe the nature of solutions and how to quantify the concentration<br />

of a solution.<br />

Properties of Solutions<br />

Solution Composition<br />

Solute - substance which is dissolved (if liquid-liquid, the one you have less of is considered the<br />

solute)<br />

Solvent - substance which is doing the dissolving.<br />

Molarity (M) - the number of moles of solute per liter of solution.<br />

Mass percent (weight percent) - percent by mass of solute in the solution.<br />

The way in which we all awys see in chemistry<br />

diffrent from molarity beccause of what you<br />

are dividing it by.<br />

The solution is produced by the mixture<br />

of the solute and solvent.<br />

Molality - the number of moles of solute per kilogram of solvent.<br />

NaCL+ H2O<br />

Energies of Solution Formation<br />

Three steps in creating a liquid solution<br />

NA+ Cl-<br />

individuals<br />

Step 1 - break up the solute into individual components (expanding the solute).<br />

Step 2 - overcoming intermolecular forces in the solvent to make room for the solute<br />

(expanding the solvent).<br />

It takes energey in order to<br />

split the molecules apart<br />

Sodium will atttach to the water<br />

molecule<br />

Step 3 - allowing the solute and solvent to interact to form the solution.<br />

Anything that has a postive or nagative electricity will pass through.<br />

Enthalpy - a thermodynamic quantity equivalent to the total heat content of a system. It is equal to the<br />

internal energy of the system plus the product of pressure and volume.<br />

Enthalpy (heat) of solution - sum of the energies it takes to dissolve a substance.<br />

Everthing we dissolve has diffrent amounts of enthalpy.<br />

Enthalpy (heat) of hydration - represents the enthalpy change associated with the dispersal of a<br />

gaseous solute in water.<br />

LIght dissolve ligts . Polar<br />

Processes which require large amounts of energy tend not to occur. thing dissolve polar things and as<br />

well non polar dissolve non polars .<br />

Factors Affecting Solubility<br />

Since it is the molecular structure that determines polarity, there should be a definite connection<br />

between structure and solubility.<br />

Like dissolves like - the rule says that most typically, polar solutes can dissolve in polar solvents and<br />

non-polar solutes can dissolve in non-polar solvents. But, polar solutes rarely dissolve in non-polar<br />

solvents and vice versa.<br />

134


Structure effects: determines what kind of substance will be able to dissolve the sample.<br />

hydrophobic - water-fearing pressure affect more gasses than it does to liquids.<br />

hydrophilic - water-loving<br />

While pressure has little effect on the solubilities of solids or liquids, it does significantly increase the<br />

solubility of a gas.<br />

Pressure effects: gas solubility increases with increased pressure.<br />

Henry's Law: the amount of a gas dissolved in a solution is directly proportional to the pressure of the<br />

gas above the solution.<br />

P = kC<br />

P represents the partial pressure of the gas, C represents the concentration of the dissolved gas, k is<br />

a constant of the particular solution.<br />

Solubility and Pressure are Directly Related<br />

Dilution is the process of decreasing the concentration of a solute in solution, usually simply by mixing<br />

with more solvent. To dilute a solution means to add more solvent without the addition of more solute.<br />

The resulting solution is thoroughly mixed so as to ensure that all parts of the solution are identical.<br />

Temperature effects - the solubility of most solids increases with temperature.<br />

Inverse relatiion ship. One goes up the other ggoes down,<br />

The Vapor Pressures of Solutions<br />

Volatile - quantified by the tendency of a substance to vaporize. Volatility is directly related to a<br />

substance's vapor pressure. At a given temperature, a substance with higher vapor pressure<br />

vaporizes more readily than a substance with a lower vapor pressure.<br />

Nonvolatile - does not readily form a vapor.<br />

Nonvolatile solutes lowers the vapor pressure of a solvent. The nonvolatile solute decreases the<br />

number of solvent molecules per unit volume. Thus it lowers the number of solvent molecules at the<br />

surface, and it should proportionately lower the escaping tendency of the solvent molecules.<br />

Boiling-Point elevation and Freezing-Point Depression<br />

Colligative properties - depend on the number, and not the identity of the solute particles in an ideal<br />

solution. ex. - freezing-point depression and boiling-point elevation.<br />

Boiling-point elevation - a nonvolatile solute elevates the boiling point of the solvent.<br />

Freezing-point depression - the water in the solution has a lower vapor pressure than that of pure ice.<br />

http://slideplayer.com/slide/10775304/<br />

Putting salt makes it less likely to be melted next time in the salt.<br />

135


The Learning Goal for this assignment is:<br />

Describes phase transations in terms of kinetic molecular theory<br />

The System and the Surroundings in <strong>Chemistry</strong><br />

Thermochemistry<br />

The system is the part of the universe we wish to focus our attention on. In the world of chemistry, the<br />

system is the chemical reaction. For example:<br />

2H2 + O2 ---> 2H2O<br />

The system consists of those molecules which are reacting.<br />

The surroundings are everything else; the rest of the universe. For example, say the above reaction is<br />

happening in gas phase; then the walls of the container are part of the surroundings.<br />

There are two important issues:<br />

1. a great majority of our studies will focus on the change in the amount of energy, not the<br />

absolute amount of energy in the system or the surroundings.<br />

2. regarding the direction of energy flow, we have a "sign convention."<br />

Two possibilities exist concerning the flow of energy between system and surroundings:<br />

1. The system can have energy added to it, which increases its amount and lessens the energy<br />

amount in the surroundings.<br />

2. The system can have energy removed from it, thereby lowering its amount and increasing the<br />

amount in the surroundings.<br />

We will signify an increase in energy with a positive sign and a loss of energy with a negative sign.<br />

Also, we will take the point-of-view from the system. Consequently:<br />

1. When energy (heat or work) flow out of the system, the system decreases in its amount. This<br />

is assigned a negative sign and is called exothermic.<br />

2. When energy (heat or work) flows into the system, the system increases its energy amount.<br />

This is assigned a positive sign and is called endothermic.<br />

We do not discuss chemical reactions from the surrounding's point-of-view. Only from the system's.<br />

Notes: All reaction accur due to the energy<br />

it sorrunding has or else it wouldnt funtion and when changing of phases accur temperatue and presuure changes.Endothermic r<br />

eaction is the process or reaction in which the system absorbs energy from its surroundings; usually,heat but not always. Examples<br />

of this would beas to liquid:Condensation, Liquid to solid;freezing, amd gas to solid ; deposition. While exothermic reactions are a<br />

chemical reaction that releases energy by heat. Exothermic means heat is given off or heat is flowing Some examples of e<br />

exothermic reactions would be, solid to liquid; melting, liquid to gas :vaporizing, and solid togas sublimation<br />

136


Specific Heat<br />

Here is the definition of specific heat:<br />

the amount of heat necessary for 1.00 gram of a substance to change 1.00 °C<br />

Note the two important factors:<br />

1. It's 1.00 gram of a substance<br />

2. and it changes 1.00 °C<br />

Keep in mind the fact that this is a very specific value. It is only for one gram going one degree. The<br />

specific heat is an important part of energy calculations since it tells you how much energy is needed<br />

to move each gram of the substance one degree.<br />

Every substance has its own specific heat and each phase has its own distinct value. In fact, the<br />

specific heat value of a substance changes from degree to degree, but we will ignore that.<br />

The units are often Joules per gram-degree Celsius (J/g*°C). Sometimes the unit J/kg K is also used.<br />

This last unit is technically the most correct unit to use, but since the first one is quite common, you<br />

will need to know both.<br />

I will ignore calorie-based units almost entirely.<br />

Here are the specific heat values for water:<br />

Phase J g¯1 °C¯1 J kg¯1<br />

K¯1<br />

Gas 2.02 2.02 x 10 3<br />

Liquid 4.184 4.184 x 10 3<br />

Solid 2.06 2.06 x 10 3<br />

Notice that one set of values is simply 1000 times bigger than the other. That's to offset the influence<br />

of going from grams to kilograms in the denominator of the unit.<br />

Notice that the change from Celsius to Kelvin does not affect the value. That is because the specific<br />

heat is measured on the basis of one degree. In both scales (Celsius and Kelvin) the jump from one<br />

degree to the next are the same "distance." Sometimes a student will think that 273 must be involved<br />

somewhere. Not in this case.<br />

Specific heat values can be looked up in reference books. Typically, in the classroom, you will not be<br />

asked to memorize any specific heat values. However, you may be asked to memorize the values for<br />

the three phases of water.<br />

As you go about the Internet, you will find different values cited for specific heats of a given<br />

substance. For example, I have seen 4.186 and 4.187 used in place of 4.184 for liquid water. None of<br />

the values are wrong, it's just that specific heat values literally change from degree to degree. What<br />

happens is that an author will settle on one particular value and use it. Often, the one particular value<br />

used is what the author used as a student.<br />

Hence, 4.184.<br />

137


The Time-Temperature Graph<br />

We are going to heat a container that has 72.0 grams of ice (no liquid water yet!) in it. To make the<br />

illustration simple, please consider that 100% of the heat applied goes into the water. There is no loss<br />

of heat into heating the container and no heat is lost to the air.<br />

Let us suppose the ice starts at -10.0 °C and that the pressure is always one atmosphere. We will<br />

end the example with steam at 120.0 °C.<br />

There are five major steps to discuss in turn before this problem is completely solved. Here they are:<br />

1. the ice rises in temperature from -10.0 to 0.00 °C.<br />

2. the ice melts at 0.00 °C.<br />

3. the liquid water then rises in temperature from zero to 100.0 °C.<br />

4. the liquid water then boils at 100.0 °C.<br />

5. the steam then rises in temperature from 100.0 to 120.0 °C<br />

Each one of these steps will have a calculation associated with it. WARNING: many homework and<br />

test questions can be written which use less than the five steps. For example, suppose the water in<br />

the problem above started at 10.0 °C. Then, only steps 3, 4, and 5 would be required for solution.<br />

To the right is the type of graph which is typically used to<br />

show this process over time.<br />

You can figure out that the five numbered sections on the<br />

graph relate to the five numbered parts of the list just above<br />

the graph.<br />

Also, note that numbers 2 and 4 are phases changes: solid<br />

to liquid in #2 and liquid to gas in #4.<br />

Q=mcΔT<br />

where ΔT is (Tf – Ti)<br />

Here are some symbols that will be used, A LOT!!<br />

Δt = the change in temperature from start to finish in degrees Celsius (°C)<br />

m = mass of substance in grams<br />

c = the specific heat. Its unit is Joules per gram X degree Celsius (J / g °C is one way to write<br />

the unit; J g¯1 °C¯1 is another)<br />

q = the amount of heat involved, measured in Joules or kilojoules (symbols = J and kJ)<br />

mol = moles of substance.<br />

ΔH is the symbol for the molar heat of fusion and ΔH is the symbol for the molar heat of<br />

vaporization.<br />

We will also require the molar mass of the substance. In this example it is water, so the molar mass is<br />

18.0 g/mol.<br />

Notes:<br />

Specific heat is the specific amount of energy (heat) necessary for a (!) gram of a substance to change to<br />

1 degree celsuis.Every substance has its own specific heat and every difrrent phase contains a distinct<br />

value.Stuff that you should Always look before you solve would be if the tempeture ice changes from<br />

,as well the temperature change in water . BUt as well what temperture water boils and the steam that<br />

rise in temp. Most importantly when using the eqauation Q=-MC^T .Remember, ^T the change in<br />

temperature in celsuis. And M is the mass of a subtance. WHile C is the specific heat your<br />

dealing with. Q equals the amount of heat involved in joules.<br />

138


Step One: solid ice rises in temperature<br />

As we apply heat, the ice will rise in temperature until it<br />

arrives at its normal melting point of zero Celsius.<br />

Once it arrives at zero, the Δt equals 10.0 °C.<br />

Here is an important point: THE ICE HAS NOT MELTED<br />

YET.<br />

At the end of this step we have SOLID ice at zero<br />

degrees. It has not melted yet. That's an important point.<br />

Each gram of water requires a constant amount of energy<br />

to go up each degree Celsius. This amount of energy is<br />

called specific heat and has the symbol c.<br />

72.0 grams of ice (no liquid water yet!) has changed 10.0 °C. We need to calculate the energy<br />

needed to do this.<br />

This summarizes the information needed:<br />

Δt = 10 °C<br />

The mass = 72.0 g<br />

c = 2.06 Joules per gram-degree Celsius<br />

The calculation needed, using words & symbols is:<br />

q = (mass) (Δt) (c)<br />

Why is this equation the way it is?<br />

Think about one gram going one degree. The ice needs 2.06 J for that. Now go the second degree.<br />

Another 2.06 J. Go the third degree and use another 2.06 J. So one gram going 10 degrees needs<br />

2.06 x 10 = 20.6 J. Now we have 72 grams, so gram #2 also needs 20.6, gram #3 needs 20.6 and so<br />

on until 72 grams.<br />

With the numbers in place, we have:<br />

q = (72.0 g) (10 °C) (2.06 J/g °C)<br />

So we calculate and get 1483.2 J. We won't bother to round off right now since there are four more<br />

calculations to go. Maybe you can see that we will have to do five calculations and then sum them all<br />

up.<br />

One warning before going on: three of the calculations will yield J as the unit on the answer and two<br />

will give kJ. When you add the five values together, you MUST have them all be the same unit.<br />

In the context of this problem, kJ is the preferred unit. You might want to think about what 1483.2 J is<br />

in kJ.<br />

Notes:<br />

When we add heat to ice it would lead to the temperture of the ice will rise until it tranformers to its normal melting pointof zero Celsius.<br />

Once it become zero it will becom 10 degrees celsuis. In order to make make each gram of water youmust need a constant to go up a<br />

degree in celsuis.These amount of energy is refferdto as C Without the constant amount of energy the temperature in celsuis could go up. Y<br />

ou woud use the formula Q= Mass*T^ *(C). M i mass and T^ is specific heat while C is temperature in joules. In these equation all you have<br />

to do is multiply everthing in order to get your result whivh would be in joules. Example would be Q= 2(mass) g *4.18 (water specic heat)<br />

3 j/g c change. After you multyply all the number yopu will get yur results which would be 25.08 j. you would then put in significant figures<br />

which would be 3 signifcant figures. <strong>Final</strong>ly your final answer would be 25.1 J<br />

139


Step Two: solid ice melts<br />

Now, we continue to add energy and the ice begins to<br />

melt.<br />

However, the temperature DOES NOT CHANGE. It<br />

remains at zero during the time the ice melts.<br />

Each mole of water will require a constant amount of<br />

energy to melt. That amount is named the molar heat of<br />

fusion and its symbol is ΔHf. The molar heat of fusion is<br />

the energy required to melt one mole of a substance at its<br />

normal melting point. One mole of solid water, one mole<br />

of solid benzene, one mole of solid lead. It does not<br />

matter. Each substance has its own value.<br />

During this time, the energy is being used to overcome water molecules' attraction for each other,<br />

destroying the three-dimensional structure of the ice.<br />

The unit for this is kJ/mol. Sometimes you see older references that use kcal/mol. The conversion<br />

between calories and Joules is 4.184 J = 1.000 cal.<br />

Sometimes you also see this number expressed "per gram" rather than "per mole." For example,<br />

water's molar heat of fusion is 6.02 kJ/mol. Expressed per gram, it is 334.16 J/g.<br />

Typically, the term "heat of fusion" is used with the "per gram" value.<br />

72.0 grams of solid water is 0.0 °C. It is going to melt AND stay at zero degrees. This is an important<br />

point. While the ice melts, its temperature will remain the same. We need to calculate the energy<br />

needed to do this.<br />

This summarizes the information needed:<br />

ΔHf = 6.02 kJ/mol<br />

The mass = 72.0 g<br />

The molar mass of H2O = 18.0 gram/mol<br />

The calculation needed, using words & symbols is:<br />

q = (moles of water) (ΔHf)<br />

We can rewrite the moles of water portion and make the equation like this:<br />

q = (grams water / molar mass of water) (ΔHf)<br />

Why is this equation the way it is?<br />

Think about one mole of ice. That amount of ice (one mole or 18.0 grams) needs 6.02 kilojoules of<br />

energy to melt. Each mole of ice needs 6.02 kilojoules. So the (grams water / molar mass of water) in<br />

the above equation calculates the amount of moles.<br />

With the numbers in place, we have:<br />

q = (72.0 g / 18.0 g mol¯1 ) (6.02 kJ / mol)<br />

So we calculate and get 24.08 kJ. We won't bother to round off right now since there are three more<br />

calculations to go. We're doing the second step now. When all five are done, we'll sum them all up.<br />

140


Step Three: liquid water rises in temperature<br />

Once the ice is totally melted, the temperature can now<br />

begin to rise again.<br />

It continues to go up until it reaches its normal boiling<br />

point of 100.0 °C.<br />

Since the temperature went from zero to 100, the Δt is<br />

100.<br />

Here is an important point: THE LIQUID HAS NOT<br />

BOILED YET.<br />

At the end of this step we have liquid water at 100 degrees. It has not turned to steam yet.<br />

Each gram of water requires a constant amount of energy to go up each degree Celsius. This amount<br />

of energy is called specific heat and has the symbol c. There will be a different value needed,<br />

depending on the substance being in the solid, liquid or gas phase.<br />

72.0 grams of liquid water is 0.0 °C. It is going to warm up to 100.0 °C, but at that temperature, the<br />

water WILL NOT BOIL. We need to calculate the energy needed to do this.<br />

This summarizes the information needed:<br />

Δt = 100.0 °C (100.0 °C – 0.0 °C)<br />

The mass = 72.0 g<br />

c = 4.184 Joules per gram-degree Celsius<br />

The calculation needed, using words & symbols is:<br />

q = (mass) (Δt) (c)<br />

Why is this equation the way it is?<br />

Think about one gram going one degree. The liquid water needs 4.184 J for that. Now go the second<br />

degree. Another 4.184 J. Go the third degree and use another 4.184 J. So one gram going 100<br />

degrees needs 4.184 x 100 = 418.4 J. Now we have 72 grams, so gram #2 also needs 418.4, gram<br />

#3 needs 418.4 and so on until 72 grams.<br />

With the numbers in place, we have:<br />

q = (72.0 g) (100.0 °C) (4.184 J/g °C)<br />

So we calculate and get 30124.8 J. We won't bother to round off right now since there are two more<br />

calculations to go. We will have to do five calculations and then sum them all up.<br />

Notes:<br />

When a solid melts it is a exothermic reaction due to the fact those types of reaction release energy. while endothermic reaction<br />

areabsorbing eenrgy like freezing and others. While ice melt the temperature of it stays the same which is 0 degrees. But each<br />

molle of water would need enrgy inorder to break all the bond each molecule has to completly melt. When the enrgy is being used<br />

to melt the solid molecular collision of one anothe begins which leads to the destruction of the structure of the ice. Furthemore<br />

when ice gets completleyme elted and becomes a liquid a\it can further go through another state in which the temperture begins<br />

to rise again. It will go up to the certain boiling point it all depends on the subtance to dertermine the boiling point. Each water<br />

molecule need a specific heat to begin boiling which is called specific heat .<br />

141


Step Four: liquid water boils<br />

Now, we continue to add energy and the water begins to<br />

boil.<br />

However, the temperature DOES NOT CHANGE. It<br />

remains at 100 during the time the water boils.<br />

Each mole of water will require a constant amount of<br />

energy to boil. That amount is named the molar heat of<br />

vaporization and its symbol is ΔH. The molar heat of<br />

vaporization is the energy required to boil one mole of a<br />

substance at its normal boiling point. One mole of liquid water, one mole of liquid benzene, one mole<br />

of liquid lead. It does not matter. Each substance has its own value.<br />

During this time, the energy is being used to overcome water molecules' attraction for each other,<br />

allowing them to move from close together (liquid) to quite far apart (the gas state).<br />

The unit for this is kJ/mol. Sometimes you see older references that use kcal/mol. The conversion<br />

between calories and Joules is 4.184 J = 1.000 cal.<br />

Typically, the term "heat of vaporization" is used with the "per gram" value.<br />

72.0 grams of liquid water is at 100.0 °C. It is going to boil AND stay at 100 degrees. This is an<br />

important point. While the water boils, its temperature will remain the same. We need to calculate the<br />

energy needed to do this.<br />

This summarizes the information needed:<br />

ΔH = 40.7 kJ/mol<br />

The mass = 72.0 g<br />

The molar mass of H2O = 18.0 gram/mol<br />

The calculation needed, using words & symbols is:<br />

q = (moles of water) (ΔH)<br />

We can rewrite the moles of water portion and make the equation like this:<br />

q = (grams water / molar mass of water) (ΔH)<br />

Why is this equation the way it is?<br />

Think about one mole of liquid water. That amount of water (one mole or 18.0 grams) needs 40.7<br />

kilojoules of energy to boil. Each mole of liquid water needs 40.7 kilojoules to boil. So the (grams<br />

water / molar mass of water) in the above equation calculates the amount of moles.<br />

With the numbers in place, we have:<br />

q = (72.0 g / 18.0 g mol¯1 ) (40.7 kJ / mol)<br />

So we calculate and get 162.8 kJ. We won't bother to round off right now since there is one more<br />

calculation to go. We're doing the fourth step now. When all five are done, we'll sum them all up.<br />

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Step Five: steam rises in temperature<br />

Once the water is completely changed to steam, the<br />

temperature can now begin to rise again.<br />

It continues to go up until we stop adding energy. In this<br />

case, let the temperature rise to 120 °C.<br />

Since the temperature went from 100 °C to 120°C, the Δt<br />

is 20°C.<br />

Each gram of water requires a constant amount of energy<br />

to go up each degree Celsius. This amount of energy is called specific heat and has the symbol c.<br />

There will be a different value needed, depending on the substance being in the solid, liquid or gas<br />

phase.<br />

72.0 grams of steam is 100.0 °C. It is going to warm up to 120.0 °C. We need to calculate the energy<br />

needed to do this.<br />

This summarizes the information needed:<br />

Δt = 20 °C<br />

The mass = 72.0 g<br />

c = 2.02 Joules per gram-degree Celsius<br />

The calculation needed, using words & symbols is:<br />

q = (mass) (Δt) (c)<br />

Why is this equation the way it is?<br />

Think about one gram going one degree. The liquid water needs 2.02 J for that. Now go the second<br />

degree. Another 2.02 J. Go the third degree and use another 2.02 J. So one gram going 20 degress<br />

needs 2.02 x 20 = 44 J. Now we have 72 grams, so gram #2 also needs 44, gram #3 needs 44 and<br />

so on until 72 grams.<br />

I hope that helped.<br />

With the numbers in place, we have:<br />

q = (72.0 g) (20 °C) (2.02 J/g °C)<br />

So we calculate and get 2908.8 J. We won't bother to round off right now since we still need to sum<br />

up all five values.<br />

Notes:<br />

When energy added is on kept on going, it will continue to break the water and make it start boiling. But when<br />

the temperature stays constant . It remains at 100 during the time the water boils. which the mole of water will r<br />

require a constant amount of energy to boil. when energy is being used to transform water molecules'phasem,<br />

attraction for each other begins , allowing them to move from close together to quite far apart . whch means that<br />

they are mmoving very fast and are becoming far apart and free. The next step is when steam rises in the<br />

amount temperature.. Once the water has finnaly changed to steam, the temperature can now begin to rise<br />

again meaning it will once again change phases. The temperature will continues to go up until energy is no<br />

loger being added to it.<br />

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The following table summarizes the five steps and their results. Each step number is a link back to<br />

the explanation of the calculation.<br />

Converting to kJ gives us this:<br />

1.4832 kJ<br />

24.08 kJ<br />

30.1248 kJ<br />

162.8 kJ<br />

2.9088 kJ<br />

Step q 72.0 g of H2O<br />

1 1483.2 J Δt = 10 (solid)<br />

2 24.08 kJ melting<br />

3 30124.8 J Δt = 100 (liquid)<br />

4 162.8 kJ boiling<br />

5 2908.8 J Δt = 20 (gas)<br />

Summing up gives 221.3968 kJ and proper significant digits gives us 221.4 kJ for the answer.<br />

Notice how all units were converted to kJ before continuing on. Joules is a perfectly fine unit; it's just<br />

that 221,396.8 J is an awkward number to work with. Usually Joules is used for values under 1000,<br />

otherwise kJ is used.<br />

By the way, on other sites you may see kj used for kilojoules. I've also seen Kj used. Both of these<br />

are wrong symbols. kJ is the only correct symbol.<br />

Enthalpy<br />

When a process occurs at constant pressure, the heat evolved (either released or absorbed) is equal<br />

to the change in enthalpy. Enthalpy (H) is the sum of the internal energy (U) and the product of<br />

pressure and volume (PV) given by the equation:<br />

H=U+PV<br />

When a process occurs at constant pressure, the heat evolved (either released or absorbed) is equal<br />

to the change in enthalpy. Enthalpy is a state function which depends entirely on the state<br />

functions T, P and U. Enthalpy is usually expressed as the change in enthalpy (ΔH) for a process<br />

between initial and final states:<br />

ΔH=ΔU+ΔPVΔ<br />

If temperature and pressure remain constant through the process and the work is limited to pressurevolume<br />

work, then the enthalpy change is given by the equation:<br />

ΔH=ΔU+PΔV<br />

Also at constant pressure the heat flow (q) for the process is equal to the change in enthalpy defined<br />

by the equation:<br />

ΔH=q<br />

By looking at whether q is exothermic or endothermic we can determine a relationship between ΔH<br />

and q. If the reaction absorbs heat it is endothermic meaning the reaction consumes heat from the<br />

surroundings so q>0 (positive). Therefore, at constant temperature and pressure, by the equation<br />

above, if q is positive then ΔH is also positive. And the same goes for if the reaction releases heat,<br />

144


then it is exothermic, meaning the system gives off heat to its surroundings, so q


The Learning Goal for this assignment is:<br />

Thermochemistry Review Questions<br />

Particulate Nature of Matter and Changes of State<br />

Watch the following video and answer the questions.<br />

1. How are solid particles arranged?<br />

They are arraged in a fixed framework vibrating but not staying far from their main position<br />

2. What is supplied to make a solid become a liquid?<br />

When energy (Heat)is suplied and the particles vibrate a solid becomes a liquid<br />

3. What does ice take from the environment when melting?<br />

The ice takes energy from the environment.<br />

4. What do molecules need to evaporate?<br />

Molecules also need energy inorder to evaporate it.<br />

5. Do all substance need the same amount of energy to evaporate?<br />

NO not all subtanaces need the same amount of energy to evaporate.<br />

6. Can gases change straight into solids?<br />

1. Which of the following statements about the atoms and molecules in all three states of matter is<br />

NOT true.<br />

a. Particles of matter are in constant motion<br />

b. Space exists between particles<br />

c. Adding heat increases the size of the particles<br />

d. The particles of matter are too small to be seen with the unaided eye<br />

2. Which statement is correct?<br />

a. All particles in a given substance at a given temperature have equal kinetic energy<br />

b. Heat always flows from a hotter object to a cooler object<br />

c. Heat is a measure of average kinetic energy of a substance<br />

d. Temperature measures the total kinetic energy of a substance<br />

3. In what state does matter have the most kinetic energy?<br />

a. Solid<br />

b. Liquid<br />

c. Gas<br />

d. Plasma<br />

4. In what state does matter have the least kinetic energy?<br />

a. Solid<br />

b. Liquid<br />

c. Gas<br />

d. Plasma<br />

Describes phase transations in terms of kinetic molecular theory.<br />

Yes they can if their is certain subtace used which is liquid nitrogen. Which is called deposition.<br />

5. What is the best description of the relationship between states of matter and kinetic energy?<br />

a. There is no relationship<br />

b. As kinetic energy increases the attraction between molecules increases<br />

c. As the kinetic energy decreases the attraction between molecules decreases<br />

d. As the kinetic energy increases the attraction between molecules decreases<br />

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Define the types of reactions. Give the names of the changes of States of Matter and describe the<br />

relative kinetic energy of the particles.<br />

Endothermic Reactions:<br />

process or reaction in which the system absorbs energy from its surroundings;<br />

usually,heat but not always.<br />

Gas to Liquid<br />

Liquid to Solid<br />

Gas to Solid<br />

It is when the gas turn directly into a gas which is condensation and it has a<br />

lower amount of kinetic energy.<br />

The state when a liquid tuns into a solid is called freezing. Which contains low<br />

amount of kentic energy.<br />

The state when a gas goes to a solid is deposition. Which it has a lower kentic energy,<br />

Exothermic Reactions:<br />

is a chemical reaction that releases energy by heat. Exothermic means heat is given off or heat<br />

is flowing,<br />

Solid to Liquid<br />

Changing from a solid to a liquid is reffred to the phase melting which ,has<br />

a greater kinetic energ<br />

Liquid to Gas<br />

Solid to Gas<br />

The transformation of going from a liquid to gas is called vaporization which<br />

contains a higher kentic energy,<br />

Vaporizing evrthing is boiling.<br />

Evaporation is on the surface.<br />

Going from a solud to a gas is called sublimation which as well has a hi,gher<br />

kentic energy. Example dry ice.<br />

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Phase Diagram<br />

Information on a Phase Diagram<br />

1. In each colored region the substance is in a single phase<br />

2. The lines describes the equilibrium conditions for the phases on either side of the line<br />

3. The triple point is the conditions required for all three state of matter to exist in equilibrium<br />

148


1. If this compound was at room temperature (25°C), what phase would it most likely be in?<br />

If this compuound was at room temperature of 25 degree c i think it would be most likely would be a solid,<br />

2. At what temperature would all three phases of this substance exist?<br />

The temperature that all three phases would be present wuld be 350 degrees celsuis,<br />

3. If this substance is at 45 atm and 100°C what will happen if I raise the temperature to 400°C?<br />

The pressure would increase and it would also change phases which would be sublimation,<br />

4. If this substance is at 70 atm and 500°C and the pressure is decreased to 40 atm what phase<br />

change will occur?<br />

The change will accur which is called vaporization.<br />

5. Why can’t this substance be boiled at a temperature of 200°C?<br />

The reason it can be boiled because at 200 degrees celsuis it would be a liquid so it cant be boiled.<br />

6. If I wanted to, could I drink this substance?<br />

Ithink you couldnt drink this subtance due to the fact that we couldnt.<br />

149


Heating Curve<br />

Information on a Phase Diagram<br />

1. In general the temperature goes up the longer the heating continues.<br />

Q=mc∆T<br />

2. The horizontal parts to the graph is a change of state.<br />

Q=mHf<br />

Q=mHv<br />

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1. In what part of the curve would a substance have a definite shape and definite volume?<br />

The curve that would have a defifnite shape and volunme would be I<br />

2. In what part of the curve would substance a have a definite volume but no definite shape?<br />

The curve that would have a definte volume but not a definte shape would be III.<br />

3. In what part of the curve would a substance have no definite shape or volume?<br />

The curve that the subtance would not have a definite shape or voulme would be V.<br />

4. What part of the curve represents a mixed solid/liquid phases?<br />

The curve that represent the misture of a solid and a liquid phase would be II.<br />

5. What part of the curve represents a mixed liquid/vapor phases?<br />

The part of the curtve that will represent the mixedliquid and vapor phase would be IV.<br />

6. What is the melting temperature of substance?<br />

The melting temperature of a subtance is 5 degrees celsuis,<br />

7. What is the boiling temperature of substance?<br />

The boiling point of a subtance would be about 55 degrees celsuis.<br />

8. In what part of the curve would the molecules have the lowest kinetic energy?<br />

The lowest kenetic energy would be found in curve I.<br />

9. In what part of the curve would the molecules have the greatest kinetic energy?<br />

The greates kinetic enrgy would be found in V because that is when the liquid is being heated and the<br />

kinetic enrgy is at its highest then,<br />

151


Unit 8<br />

Chapter 19 Acid and Bases<br />

The student will learn what are the different ways chemists<br />

define aids and bases, what the pH of a solution means and<br />

how chemist use acid-base reactions.<br />

Relate acidity and basicity to hydronium and hydroxyl ion concentration and<br />

pH.<br />

Students will be able to use a pH scale to identify substances as acids or bases.<br />

Students will be able to use various equipment (probeware, universal pH, etc.) to<br />

identify the pH of substances.<br />

Students will be able to calculate H3O+ and OH- concentration of various<br />

substances.<br />

pH scale<br />

Hydronium ion<br />

Arrhenius acid/base<br />

Lewis acid/base<br />

Bronsted-Lowry acid/base<br />

Strong acid/base<br />

Weak acid/base<br />

Neutralization reaction<br />

Titration<br />

Chapter 20 Oxidation-Reduction Reactions<br />

The student will learn what happens during oxidation and<br />

reduction and how to balance redox equations.<br />

Describe oxidation-reduction reactions in living and non-living systems.<br />

Students will be able to compare and contrast redox reactions.<br />

Students will be able to assign oxidation numbers to redox reactions.<br />

Students will be able to write half reactions<br />

Oxidation<br />

152


Reduction<br />

Oxidation reduction reaction<br />

Oxidation number<br />

Half reaction<br />

Electrochemical process<br />

Battery<br />

Cathode<br />

Anode<br />

Electrolysis<br />

153


The Learning Goal for this section is:<br />

The student will learn what are the different ways chemists define aids and bases, what the pH of a solution means and<br />

how chemist use acid-base reactions<br />

Acids and Bases<br />

The Observable Properties of Acids and Bases<br />

The words acid and alkaline (an older word for base) are derived from direct sensory experience.<br />

Acid Property #1:<br />

The word acid comes from the Latin word acere, which means "sour." All acids taste sour. Well<br />

known from ancient times were vinegar, sour milk and lemon juice. Aspirin (scientific name:<br />

acetylsalicylic acid) tastes sour if you don't swallow it fast enough. Other languages derive their word<br />

for acid from the meaning of sour. So, in France, we have acide. In Germany, we have säure from<br />

saure and in Russia, kislota from kisly.<br />

Base Property #1:<br />

The word "base" has a more complex history (see below) and its name is not related to taste. All<br />

bases taste bitter. For example, mustard is a base. It tastes bitter. Many medicines, because they are<br />

bases, taste bitter. This is the reason cough syrups are advertised as having a "great grape taste."<br />

The taste is added in order to cover the bitterness of the active ingredient in cough syrup.<br />

Acid Property #2:<br />

Acids make a blue vegetable dye called litmus turn red.<br />

Acids are on the bottom and bases are at the top.<br />

And 7 is nuetral.<br />

Base Property #2:<br />

Bases are substances which will restore the original blue color of litmus after having been reddened<br />

by an acid.<br />

Acid Property #3:<br />

Acids destroy the chemical properties of bases.<br />

Base Property #3:<br />

Bases destroy the chemical properties of acids.<br />

Neutralization is the name for this type of reaction.<br />

Acid Property #4:<br />

Acids conduct an electric current.<br />

Base Property #4:<br />

Bases conduct an electric current.<br />

Acids more hygrogens. BAsese more hydroxides.<br />

GIving hydrogen is Acid. HYdroxide being given off its a base.<br />

Acid turn blue litmus red . Taste sour. ACids vorrode metals<br />

and they aree postively charged hydrogen ion H^+<br />

BAses;<br />

They turn litmus blues. Taste bitter , nehgativey chraged<br />

hydroxideions . IT also feel slippery .<br />

Most hand soaps scaps and drain cleaners are bases.<br />

Strong bases are caustic.<br />

We use soap with bases because they get rid of<br />

This is a common property shared with salts. Acids, bases and salts are grouped together into a<br />

category called electrolytes, meaning that a water solution of the given substance will conduct an<br />

electric current.<br />

Non-electrolyte solutions cannot conduct a current. The most common example of this is sugar<br />

dissolved in water.<br />

154


So far, the properties have an obvious relationship: taste, color change, mutual destruction, and<br />

response to electric current. This last property is related, but in a less obvious way. The property<br />

below identifies a unique chemical reaction that acids and bases engage in.<br />

Acid Property #5:<br />

Upon chemically reacting with an active metal, acids will evolve hydrogen gas (H2). The key word, of<br />

course, is active. Some metals, like gold, silver or platinum, are rather unreactive and it takes rather<br />

extreme conditions to get these "unreactive" metals to react. Not so with the metals in this property.<br />

They include the alkali metals (Group I, Li to Rb), the alkaline earth metals (Group II, Be to Ra), as<br />

well as zinc and aluminum. Just bring the acid and the metal together at anything close to room<br />

temperature and you get a reaction. Here's a sample reaction:<br />

Zn + 2 HCl(aq) ---> ZnCl2 + H2<br />

Another common acid reaction some sources mention is that acids react with carbonates (and<br />

bicarbonates) to give carbon dioxide gas:<br />

HCl + NaCO3 ---> CO2 + H2O + NaCl<br />

Base Property #5:<br />

Bases feel slippery, sometimes people say soapy. This is because they dissolve the fatty acids and<br />

oils from your skin and this cuts down on the friction between your fingers as you rub them together.<br />

In essence, the base is making soap out of you. Yes, bases are involved in the production of soap! In<br />

the early years of soap making, the soaps were very harsh on the skin and clothes due to the high<br />

base content. Even today, people with very sensitive skin must sometimes use a non-soap-based<br />

product for bathing.<br />

It was not until more modern times that the chemical nature (as opposed to observable properties) of<br />

acids and bases began to be explored. That leads to this property that is not directly observable by<br />

the senses.<br />

Acid Property #6:<br />

Acids produce hydrogen ion (H + ) in solution. A more correct formula for what is produced is that of the<br />

hydronium ion, H3O + . Both formulas are used interchangeably.<br />

Acid base theories: Svante Arrhenius<br />

I. Introduction<br />

The basic idea is that certain substances remain ionized in solution all the time. Today, everyone<br />

accepts this without question, but it was the subject of much dissention and disagreement in 1884,<br />

when a twenty-five-year-old Arrhenius presented and defended his dissertation.<br />

II. The Acid Base Theory<br />

Acid - any substance which delivers hydrogen ion (H + ) to the solution.<br />

Base - any substance which delivers hydroxide ion (OH¯) to the solution.<br />

Here is a generic acid dissociating, according to Arrhenius:<br />

HA ---> H + + A¯<br />

155


This would be a generic base:<br />

XOH ---> X + + OH¯<br />

When acids and bases react according to this theory, they neutralize each other, forming water and a<br />

salt:<br />

HA + XOH ---> H2O + XA<br />

Keeping in mind that the acid, the base and the salt all ionize, we can write this:<br />

<strong>Final</strong>ly, we can drop all spectator ions, to get this:<br />

H + + A¯ + X + + OH¯ ---> H2O + X + + A¯<br />

H + + OH¯ ---> H2O<br />

These ideas covered all of the known acids at the time (the usual suspects like hydrochloric acid,<br />

acetic acid, and so on) and most of the bases (sodium hydroxide, potassium hydroxide, calcium<br />

hydroxide and so on). HOWEVER, and it is a big however, the theory did not explain why ammonia<br />

(NH3) was a base. There are other problems with the theory also.<br />

III. Problems with Arrhenius' Theory<br />

1. The solvent has no role to play in Arrhenius' theory. An acid is expected to be an acid in any<br />

solvent. This was found to not be the case. For example, HCl is an acid in water, behaving in<br />

the manner Arrhenius expected. However, if HCl is dissolved in benzene, there is no<br />

dissociation, the HCl remaining as un-dissociated molecules. The nature of the solvent plays a<br />

critical role in acid-base properties of substances.<br />

2. All salts in Arrhenius' theory should produce solutions that are neither acidic or basic. This is<br />

not the case. If equal amounts of HCl and ammonia react, the solution is slightly acidic. If equal<br />

amounts of acetic acid and sodium hydroxide are reacted, the resulting solution is basic.<br />

Arrhenius had no explanation for this.<br />

3. The need for hydroxide as the base led Arrhenius to propose the formula NH4OH as the<br />

formula for ammonia in water. This led to the misconception that NH4OH is the actual base,<br />

not NH3.<br />

In fact, by 1896, several years before Arrhenius announced his theory, it had been recognized that<br />

characteristic base properties where just as evident in such solvents as aniline, where no hydroxide<br />

ions were possible.<br />

4. H + , a bare proton, does not exist for very long in water. The proton affinity of H2O is about 799<br />

kJ/mol. Consequently, this reaction:<br />

H2O + H + ---> H3O +<br />

happens to a very great degree. The "concentration" of free protons in water has been estimated to<br />

be 10¯130 M. A rather preposterous value, indeed.<br />

The Arrhenius theory of acids and bases will be fully supplanted by the theory proposed<br />

independently by Johannes Brønsted and Thomas Lowry in 1923.<br />

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The acid base theory of Brønsted and Lowry<br />

I. Introduction<br />

In 1923, within several months of each other, Johannes Nicolaus Brønsted (Denmark) and Thomas<br />

Martin Lowry (England) published essentially the same theory about how acids and bases behave.<br />

Since they came to their conclusions independently of each other, both names have been used for<br />

the theory name.<br />

An acid is a protoon (Hydrogen) donor while a base is a proton (Hydrogen )<br />

II. The Acid Base Theory<br />

accepttor,<br />

Using the words of Brønsted:<br />

". . . acids and bases are substances that are capable of splitting off or taking up hydrogen ions,<br />

respectively."<br />

Or an acid-base reaction consists of the transfer of a proton from an acid to a base. KEEP THIS<br />

THOUGHT IN MIND!!<br />

Here is a more recent way to say the same thing:<br />

An acid is a substance from which a proton can be removed.<br />

A base is a substance that can remove a proton from an acid.<br />

Remember: proton, hydrogen ion and H + all mean the same thing<br />

Very common in the chemistry world is this definition set:<br />

An acid is a "proton donor."<br />

A base is a "proton acceptor."<br />

In an acid, the hydrogen ion is bonded to the rest of the molecule. It takes energy (sometimes a little,<br />

sometimes a lot) to break that bond. So the acid molecule does not "give" or "donate" the proton, it<br />

has it taken away. In the same sense, you do not donate your wallet to the pickpocket, you have it<br />

removed from you.<br />

The base is a molecule with a built-in "drive" to collect protons. As soon as the base approaches the<br />

acid, it will (if it is strong enough) rip the proton off the acid molecule and add it to itself.<br />

Now this is where all the fun stuff comes in that you get to learn. You see, some bases are stronger<br />

than others, meaning some have a large "desire" for protons, while other bases have a weaker drive.<br />

It's the same way with acids, some have very weak bonds and the proton is easy to pick off, while<br />

other acids have stronger bonds, making it harder to "get the proton."<br />

One important contribution coming from Lowry has to do with the state of the hydrogen ion in solution.<br />

In Brønsted's announcement of the theory, he used H + . Lowry, in his paper (actually a long letter to<br />

the editor) used the H3O + that is commonly used today.<br />

III. Sample Equations written in the Brønsted-Lowry Style<br />

A. Reactions that proceed to a large extent:<br />

Chlorine is a conjuctive base.<br />

157


HCl + H2O ⇌ H3O + + Cl¯<br />

HCl - this is an acid, because it has a proton available to be transferred.<br />

H2O - this is a base, since it gets the proton that the acid lost.<br />

Now, here comes an interesting idea:<br />

H3O + - this is an acid, because it can give a proton.<br />

Cl¯ - this is a base, since it has the capacity to receive a proton.<br />

Notice that each pair (HCl and Cl¯ as well as H2O and H3O + differ by one proton (symbol = H + ). These<br />

pairs are called conjugate pairs.<br />

HNO3 + H2O ⇌ H3O + + NO3¯<br />

The acids are HNO3 and H3O + and the bases are H2O and NO3¯.<br />

Remember that an acid-base reaction is a competition between two bases (think about it!) for a<br />

proton. If the stronger of the two acids and the stronger of the two bases are reactants (appear on the<br />

left side of the equation), the reaction is said to proceed to a large extent.<br />

Here are some more conjugate acid-base pairs to look for:<br />

H2O and OH¯<br />

HCO3¯ and CO3 2¯<br />

H2PO4¯ and HPO4 2¯<br />

HSO4¯ and SO4 2¯<br />

PH is telling us how concentrated the subtance is not neccesarly if its high or low<br />

basiccaly not the strength.<br />

CHEMICAL EQUATION:HA+BOH ->H20+BA<br />

Ion eqaution: H^+ +A^-, +B^+ +OH^- -> h20 + B^+ + A^-<br />

Net ion equation: H^+ + OH^- -> H2O<br />

NH4 + and NH3<br />

CH3NH3 + and CH3NH2<br />

HC2H3O2 and C2H3O2¯<br />

B. Reactions that proceed to a small extent:<br />

If the weaker of the two acids and the weaker of the two bases are reactants (appear on the left side<br />

of the equation), the reaction is said to proceed to only a small extent:<br />

A<br />

B<br />

C D<br />

HC2H3O2 + H2O ⇌ H3O + Conjugate pair is A and d.<br />

+ C2H3O2¯<br />

The other is B and c .<br />

H2o is acting like a base then like a acid because you can see the<br />

change because of the negative.<br />

NH3 + H2O ⇌ NH4 + + OH¯<br />

Identify the conjugate acid base pairs in each reaction.<br />

HC 2H 3O 2 and C 2H 3O 2¯<br />

is one conjugate pair.<br />

H 2O and H 3O + is the other.<br />

NH 3 and NH 4<br />

+<br />

is one pair.<br />

H 2O and OH¯ is the other.<br />

Notice that H 2O in the first equation is acting as a base and in the second equation is acting as an acid.<br />

Conjugate pair A and C<br />

Thesecion is B And D .<br />

158


IV. Problems with the Theory<br />

This theory works very nicely in all protic solvents (water, ammonia, acetic acid, etc.), but fails to<br />

explain acid base behavior in aprotic solvents such as benzene and dioxane. That job will be left for a<br />

more general theory, such as the Lewis Theory of Acids and Bases.<br />

The Lewis theory of acids and bases<br />

I. Introduction<br />

Lewis gives his definition of an acid and a base:<br />

"We are inclined to think of substances as possessing acid or basic properties, without having a<br />

particular solvent in mind. It seems to me that with complete generality we may say that a basic<br />

substance is one which has a lone pair of electrons which may be used to complete the stable group<br />

of another atom, and that an acid is one which can employ a lone pair from another molecule in<br />

completing the stable group of one of its own atoms."<br />

"In other words, the basic substance furnishes a pair of electrons for a chemical bond, the acid<br />

substance accepts such a pair."<br />

It is important to make two points here:<br />

1. NO hydrogen ion need be involved.<br />

2. NO solvent need be involved.<br />

The Lewis theory of acids and bases is more general than the "one sided" nature of the Bronsted-<br />

Lowry theory. Keep in mind that Bronsted-Lowry, which defines an acid as a proton donor and a base<br />

as a proton acceptor, REQUIRES the presence of a solvent, specifically a protic solvent, of which<br />

water is the usual example. Since almost all chemistry is done in water, the fact that this limits the<br />

Bronsted-Lowry definition is of little practical consequence.<br />

The Lewis definitions of acid and base do not have the constraints that the Bronsted-Lowry theory<br />

does and, as we shall see, many more reactions were seen to be acid base in nature using the Lewis<br />

definition than when using the Bronsted-Lowry definitions.<br />

II. The Acid Base Theory<br />

The modern way to define a Lewis acid and base is a bit more concise than above:<br />

Acid: an electron acceptor.<br />

Base: an electron donor.<br />

A "Lewis acid" is any atom, ion, or molecule which can accept electrons and a "Lewis base" is any<br />

atom, ion, or molecule capable of donating electrons. However, a warning: many textbooks will say<br />

"electron pair" where I have only written "electron." The truth is that it sometimes is an electron pair<br />

and sometimes it is not.<br />

It turns out that it may be more accurate to say that "Lewis acids" are substances which are electrondeficient<br />

(or low electron density) and "Lewis bases" are substances which are electron-rich (or high<br />

electron density).<br />

159


Several categories of substances can be considered Lewis acids:<br />

1. positive ions<br />

2. having less than a full octet in the valence shell<br />

3. polar double bonds (one end)<br />

4. expandable valence shells<br />

Several categories of substances can be considered Lewis bases:<br />

1. negative ions<br />

2. one of more unshared pairs in the valence shell<br />

3. polar double bonds (the other end)<br />

4. the presence of a double bond<br />

Sören Sörenson and the pH scale<br />

I. Short Historical Introduction<br />

In the late 1880's, Svante Arrhenius proposed that acids were substances that delivered hydrogen ion<br />

to the solution. He has also pointed out that the law of mass action could be applied to ionic<br />

reactions, such as an acid dissociating into hydrogen ion and a negatively charged anion.<br />

This idea was followed up by Wilhelm Ostwald, who calculated the dissociation constants (the<br />

modern symbol is Ka) of many weak acids. Ostwald also showed that the size of the constant is a<br />

measure of an acid's strength.<br />

By 1894, the dissociation constant of water (today called Kw) was measured to the modern value of<br />

1 x 10¯14 .<br />

In 1904, H. Friedenthal recommended that the hydrogen ion concentration be used to characterize<br />

solutions. He also pointed out that alkaline (modern word = basic) solutions could also be<br />

characterized this way since the hydroxyl concentration was always 1 x 10¯14 ÷ the hydrogen ion<br />

concentration. Many consider this to be the real introduction of the pH scale.<br />

III. The Introduction of pH<br />

Sörenson defined pH as the negative logarithm of the hydrogen ion concentration.<br />

pH = - log [H + ]<br />

Remember that sometimes H3O + is written, so<br />

pH = - log [H3O + ]<br />

means the same thing.<br />

So let's try a simple problem: The [H + ] in a solution is measured to be 0.010 M. What is the pH?<br />

The solution is pretty straightforward. Plug the [H + ] into the pH definition:<br />

pH = - log 0.010<br />

An alternate way to write this is:<br />

pH = - log 10¯2<br />

Since the log of 10¯2 is -2, we have:<br />

pH = - (- 2)<br />

Which, of course, is 2.<br />

160


Let's discuss significant figures and pH.<br />

Another sample problem: Calculate the pH of a solution in which the [H3O + ] is 1.20 x 10¯3 M.<br />

For the solution, we have:<br />

pH = - log 1.20 x 10¯3<br />

This problem can be done very easily using your calculator. However, be warned about putting<br />

numbers into the calculator.<br />

So you enter (-), log, 1.20, X10 n , (-), 3, enter.<br />

The answer, to the proper number of significant digits is: 2.921.<br />

III. Significant Figures in pH<br />

Here is the example problem: Calculate the pH of a solution where the [H + ] is 0.00100 M. (This could<br />

also be a pOH problem. The point being made is the same.)<br />

OK, you say, that's pretty easy, the answer is 3. After all, 0.00100 is 10¯3 and the negative log of 10¯3<br />

is 3.<br />

You would be graded wrong!! Why? Because the pH is not written to reflect the number of significant<br />

figures in the concentration.<br />

Notice that there are three sig figs in 0.00100. (Hopefully you remember significant figures, since you<br />

probably studied them months ago before getting to acid base stuff. THEY ARE STILL IMPORTANT!)<br />

So, our pH value should also reflect three significant figures.<br />

However, there is a special rule to remember with pH (and pOH) values. The whole number portion<br />

DOES NOT COUNT when figuring out how many digits to write down.<br />

Let's phrase that another way: in a pH (and a pOH), the only place where significant figures are<br />

contained is in the decimal portion.<br />

So, the correct answer to the above problem is 3.000. Three sig figs and they are all in the decimal<br />

portion, NOT (I repeat NOT) in the whole number portion.<br />

Practice Problems<br />

Convert each hydrogen ion concentration into a pH. Identify each as an acidic pH or a basic pH.<br />

1. 0.0015<br />

2. 5.0 x 10¯9<br />

3. 1.0<br />

4. 3.27 x 10¯4<br />

5. 1.00 x 10¯12<br />

6. 0.00010<br />

pH= -log (0.0015)= -log (0.0015)= 2.823908741 = 2.82<br />

ph=-log ( 5.0* 10^-9) = 8.301029996 = 8.30<br />

ph=-log (1.0) = 0<br />

ph=-log ( 3.27^10^-4)= 3.4852247 = 3.49<br />

ph=-log ( 1.00X 10 ^-12) = 12.000<br />

ph=-log (0.00010) = 4.000<br />

acid<br />

Base<br />

acid<br />

Acid<br />

Base<br />

acid<br />

161


1. 2.82<br />

2. 8.30<br />

3. 0.00<br />

4. 3.485<br />

5. 12.000<br />

6. 4.00<br />

Sörenson also just mentions the reverse direction. That is, suppose you know the pH and you want to<br />

get to the hydrogen ion concentration ([H + ])?<br />

Here is the equation for that:<br />

[H + ] = 10¯pH<br />

That's right, ten to the minus pH gets you back to the [H + ] (called the hydrogen ion concentration).<br />

This is actually pretty easy to do with the calculator. Here's the sample problem: calculate the [H + ]<br />

from a pH of 2.45.<br />

This problem can be done very easily using your calculator. However, be warned about putting<br />

numbers into the calculator.<br />

So you enter 2nd, 10 x , (-), 2.45, enter.<br />

The answer, to the proper number of significant digits is: .00355.<br />

The pH of an acidic pond is 5. What is the hydrogen ion concentration (moles per liter)?<br />

The answer is:<br />

pH = -log (hydrogen ion concentration)<br />

The answer was .00001. Thus, 5 = -log (.00001).<br />

We'll take the formula that you started with (pH = -log([H+])) and work to the answer (solve for [H+]).<br />

pH = - log ([H+]) Given.<br />

pH = log ([H+] (-1) ) Since logarithms are like exponents, when you multiply a log by<br />

something, you can just move it to the inside of log as an exponent.<br />

10 pH = 10 log ([H+] (-1)) Take each side to tenth power.<br />

10 pH = [H+] (-1) Since "log" is just another notation for "log base 10", when you<br />

raise a log to the tenth power, the log cancels out.<br />

[H+] = 10 (-pH)<br />

Take the reciprocal of both sides.<br />

That is the general form. To answer the specific question,<br />

5 = - log ([H+])<br />

5 = log ([H+] (-1) )<br />

10 5 = [H+] (-1)<br />

10 (-5) = [H+]<br />

[H+]<br />

= .00001 mol/L<br />

162


On your calculator you would input 10, ^, (-), 5 and you would get 0.00001.<br />

This is also the way to find the amount of OH + that are present in a base.<br />

To find the pH: -log(concentration)<br />

To find the concentration: 10 -pH<br />

Define these terms:<br />

pH scale<br />

A ph scale in which measures the acidic of a subtance. It can also measure the level of base it its. Not only thtaht ph<br />

scale can show the mixture of a basea nd aci meaning that its nuetral which the number on the ph is 7.<br />

The scale ranges from 1-14. Acids are from 1 -6 while bases are 8-14.<br />

Hydronium ion<br />

A hydronuim ion is a aqueous solution is no more than a proton. Its a bare nuclues. Contains single postive charge which<br />

is concentrated into a volume of space .The hydronium ion is an vital when their is chemicla reactions<br />

that occur in aqueous solutions.The chemical formula of a hydronuim ion is H3O<br />

Arrhenius acid/base<br />

An Arrhenius acid dissociates in water to form hydrogen ions. On the other hand, an Arrhenius base<br />

dissociates in water to form hydroxide ions. Acid is any substance which delivers hydrogen ion to the solution.<br />

While any substance which delivers hydroxide ion (OH¯) to the solution.<br />

Lewis acid/base<br />

In the Lewis theory of acid-base reactions, the bases give pairs of electrons. While on the other hand the acids take<br />

pairs of electrons. A Lewis acid is a substance, that can take in a pair of nonbonding electrons.<br />

Baicaly a Lewis acid is an electron pair acceptor.<br />

Bronsted-Lowry acid/base<br />

An acid is a substance from which a proton can be removed. A base is a substance that can remove a proton from an<br />

acid.In an acid, the hydrogen ion is bonded to the rest of the molecule. In an acid, the hydrogen ion is bonded to the<br />

rest of the molecule<br />

Strong acid/base<br />

strong acid is any acid that ionizes completely in solutions. Which menas thet it gives the greatest number of hyrogen ion or<br />

protons. While a srong base feel slippery and taste soapy. A strong base is a base that breaks completley apart<br />

in solution.<br />

Weak acid/base<br />

.A weak acid is an acid that dissociates incompfew of its hydrogen atoms into solution. Which makes it is less capable<br />

than a strongacid when giving protons away. While a strong base is a base that does not ionize fully in an<br />

aqueous solution.<br />

Neutralization reaction<br />

Neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of hydrogen<br />

ions and OH- ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7 which is<br />

nuetral not acidic nor a base but in the middle conating a bit of both.<br />

Titration<br />

Titration is a slow addition of one solution of a known concentration to a known volume of another solution of unknown<br />

concentration until the reaction reaches neutralization, which is often indicated by a color change. Two of the most<br />

common titrations are acid-base and redox titrations<br />

163


The Learning Goal for this assignment is:<br />

The student will learn what happens during oxidation and reduction and how to balance redox equations.<br />

1. Oxidation Numbers<br />

Redox Reactions<br />

Oxidation and reduction<br />

Every atom, ion or polyatomic ion has a formal oxidation number associated with it. This value<br />

compares the number of protons in an atom (positive charge) and the number of electrons assigned<br />

to that atom (negative charge).<br />

In many cases, the oxidation number reflects the actual charge on the atom, but there are many<br />

cases where it does not. Think of oxidation numbers as a bookkeeping exercise simply to keep track<br />

of where electrons go.<br />

2. Reduction<br />

Reduction means what it says: the oxidation number is reduced in reduction.<br />

This is accomplished by adding electrons. The electrons, being negative, reduce the overall oxidation<br />

number of the atom receiving the electrons.<br />

3. Oxidation<br />

Oxidation is the reverse process: the oxidation number of an atom is increased during oxidation.<br />

This is done by removing electrons. The electrons, being negative, make the atom that lost them<br />

more positive.<br />

I use this mnemonic to help me remember which is which: LEO the lion says GER.<br />

LEO = Loss of Electrons is Oxidation<br />

GER = Gain of Electrons is Reduction<br />

Another well-known mnemonic is this: OIL RIG<br />

OIL = Oxidation Is Loss (of Electrons)<br />

RIG = Reduction Is Gain (of Electrons)<br />

Another way is to simply remember that reduction is to reduce the oxidation number. Therefore,<br />

oxidation must increase the value.<br />

4. Reduction-Oxidation Reactions<br />

There are many chemical reactions in which one substance gets reduced in oxidation number<br />

(reduction) while another participating substance gets increased in oxidation number (oxidation).<br />

Such a reaction is called called a REDOX reaction. The RED, of course, comes from REDuction and<br />

OX from OXidation. However, it is pronounced re-dox and not red-ox.<br />

Here is a simple example of a redox reaction:<br />

164


Ag+ + Cu ---> Ag + Cu2+<br />

I have deliberately not balanced it and I have also written it in net ionic form. I have found that kids<br />

studying redox get confused by net ionic form and how to change a full equation into net ionic form.<br />

Redox equations need to be balanced but, except for the simplest ones, it cannot be done by<br />

inspection (also called trial and error). I take that back, complex ones can be done by trial and error. It<br />

typically takes quite a bit of work, especially when compared to how long it takes when the proper<br />

technique is used.<br />

There is a technique used to balance redox reactions. It is called "balancing by half-reactions." The<br />

basic plan will be to split the full equation into two simpler parts (called half-reactions), balance them<br />

following several standard steps, then recombine the balanced half-reactions into the final answer.<br />

This is another technique called the "ion-electron method." I plan to ignore it.<br />

Notes:<br />

when your losing electrons your gaining oxidation numbers . Reduction is gaining elcectrons.If somrething is<br />

reeducing itself its going from a higher oxidation number to a lower. Reducing oxidation agent.<br />

5. Some Definitions<br />

Oxidizing Agent - that substance which oxidizes somebody else. It is reduced in the process.<br />

Reducing Agent - that substance which reduces somebody else. It is oxidized in the process.<br />

It helps me to remember these definitions by the opposite nature of what happens. By that, I mean<br />

the oxidizing agent gets reduced and the reducing agent gets oxidized.<br />

6. Rules for Assigning Oxidation Numbers<br />

The Oxidation Number of an element corresponds to the number of electrons, e - , that an atom loses,<br />

gains, or appears to use when joining with other atoms in compounds. In determining the Oxidation<br />

Number of an atom, there are seven guidelines to follow:<br />

1. The Oxidation Number of an individual atom is 0. This includes diatomic elements such as<br />

O2 or others like P4 and S8<br />

2. The total Oxidation Number of all atoms in: a neutral species is 0 and in an ion is equal to the<br />

ion charge.<br />

3. Group 1 metals have an Oxidation Number of +1 and Group 2 an Oxidation Number of +2<br />

4. The Oxidation Number of fluorine is -1 in compounds<br />

5. Hydrogen generally has an Oxidation Number of +1 in compounds, except hydrides<br />

6. Oxygen generally has an Oxidation Number of -2 in compounds, except peroxides<br />

7. In binary metal compounds, Group 17 elements have an Oxidation Number of -1, Group 16 of -<br />

2, and Group 15 of -3.<br />

Note: The sum of the Oxidation Number s is equal to zero for neutral compounds and equal to the<br />

charge for polyatomic ion species.<br />

Now, some examples:<br />

1. What is the oxidation number of Cl in HCl?<br />

Since H = +1, the Cl must be -1 (minus one).<br />

165


2. What is the oxidation number of Na in Na2O?<br />

Since O = -2, the two Na must each be +1.<br />

3. What is the oxidation number of Cl in ClO¯?<br />

The O is -2, but since a -1 must be left over, then the Cl is +1.<br />

4. What is the oxidation number for each element in KMnO4?<br />

K = +1 because KCl exists. We know the Cl = -1 because HCl exists.<br />

O = -2 by definition<br />

Mn = +7. There are 4 oxygens for a total of -8, K is +1, so Mn must be the rest.<br />

5. What is the oxidation number of S in SO4 2¯<br />

O = -2. There are four oxygens for -8 total. Since -2 must be left over, the S must = +6.<br />

Please note that, if there is no charge indicated on a formula, the total charge is taken to be zero.<br />

Practice Problems<br />

Find oxidation numbers<br />

+5 6<br />

1. N in NO3¯<br />

+4<br />

2. C in CO3 2¯<br />

-6<br />

3. Cr in CrO4 2¯<br />

4. Cr in Cr2O7 2¯<br />

N=+5<br />

c=+4<br />

+6 -8 Cr= +6<br />

+6 -14 Cr=+6<br />

5. Fe in Fe2O3<br />

6. Pb in PbOH +<br />

+5<br />

+6<br />

-2<br />

-4<br />

7. V in VO2 +<br />

-6<br />

+1<br />

8. V in VO 2+<br />

9. Mn in MnO4¯<br />

Fe=+3<br />

Pb=+2<br />

V=+5<br />

v=+4<br />

mn=+7<br />

10. Mn in MnO4 2¯<br />

mn=+6<br />

Notes:<br />

Oxidation and reduction reactions are reactions that in which electrons are lost by an atom or ion in<br />

one reactant and also gained by an atom in another reactant. Even though electrons are gained and lost in these<br />

reactions, the balanced equation for a redox reaction does not show the electrons that are being transferred<br />

because they are being cancled out to become stable. In order to tell whether a redox reaction has occurred or if it<br />

has not , we need a way to keep track of electrons. The best way to do so is by assigning oxidation numbers to the<br />

atoms or ions involved in a chemical reaction and seeing if the reaction is oxidation or reduction by identifying if the<br />

reaction is increasinf or decreasing. If its increasing its oxidation . While if its losing or decreasing its Reduction<br />

166


7. Half Reactions<br />

A half-reaction is simply one which shows either reduction OR oxidation, but not both. Here is the<br />

example redox reaction used in a different file:<br />

Ag + + Cu → Ag + Cu 2+<br />

It has BOTH a reduction and an oxidation in it. That is why we call it a redox reaction, from REDuction<br />

and OXidation.<br />

What you must be able to do is look at a redox reaction and separate out the two half-reactions in it.<br />

To do that, identify the atoms which get reduced and get oxidized. Here are the two half-reactions<br />

from the above example:<br />

Ag+ → Ag<br />

Cu → Cu 2+<br />

The silver is being reduced, its oxidation number going from +1 to zero. The copper's oxidation<br />

number went from zero to +2, so it was oxidized in the reaction. In order to figure out the halfreactions,<br />

you MUST be able to calculate the oxidation number of an atom.<br />

Keep in mind that a half-reaction shows only one of the two behaviors we are studying. A single halfreaction<br />

will show ONLY reduction or ONLY oxidation, never both in the same equation.<br />

Also, notice that the reaction is read from left to right to determine if it is reduction or oxidation. If you<br />

read the reaction in the opposite direction (from right to left) it then becomes the other of our two<br />

choices (reduction or oxidation). For example, the silver half-reaction above is a reduction, but in the<br />

reverse direction it is an oxidation, going from zero on the right to +1 on the left.<br />

There will be times when you want to switch a half-reaction from one of the two types to the other. In<br />

that case, rewrite the entire equation and swap sides for everything involved. If I needed the silver<br />

half-reaction to be oxidation, I'd write Ag → Ag+ rather than just doing it mentally.<br />

The next step is that both half-reactions must be balanced. However, there is a twist. When you<br />

learned about balancing equation, you made equal the number of atoms of each element on each<br />

side of the arrow. That still applies, but there is one more thing: the total amount of charge on each<br />

side of the half-reaction MUST be the same.<br />

When you look at the two half-reactions above, you will see they are already balanced for atoms with<br />

one Ag on each side and one Cu on each side. So, all we need to do is balance the charge. To do<br />

this you add electrons to the more positive side. You add enough to make the total charge on each<br />

side become EQUAL.<br />

To the silver half-reaction, we add one electron:<br />

To the copper half-reaction, we add two electrons:<br />

Ag+ + e¯ ---> Ag<br />

Cu ---> Cu 2+ + 2e¯<br />

167


One point of concern: notice that each half-reaction wound up with a total charge of zero on each<br />

side. This is not always the case. You need to strive to get the total charge on each side EQUAL, not<br />

zero.<br />

One more point to make before wrapping this up. A half-reaction is a "fake" chemical reaction. It's just<br />

a bookkeeping exercise. Half-reactions NEVER occur alone. If a reduction half-reaction is actually<br />

happening (say in a beaker in front of you), then an oxidation reaction is also occurring. The two halfreactions<br />

can be in separate containers, but they do have to have some type of "chemical<br />

connection" between them.<br />

Half-Reaction Practice Problems<br />

Balance each half-reaction for atoms and charge:<br />

0<br />

-1<br />

1) Cl2 → Cl¯<br />

0 2+<br />

2) Sn → Sn 2+<br />

up oxidation<br />

down reduction<br />

The numbers are going own so its a reduction because its reducing.<br />

The reaction is going up so its oxidation.<br />

3) Fe 2+ → Fe 3+<br />

The reaction is going up so its oxidation.<br />

4) I3¯ → I¯<br />

5) ICl2¯ → I¯ (I'm being mean on this one. Hint: the iodine is the only thing reduced or oxidized.)<br />

Separate each of these redox reactions into their two half-reactions (but do not balance):<br />

6) Sn + NO3¯ →SnO2 + NO2<br />

7) HClO + Co →Cl2 + Co 2+<br />

8) NO2 →NO3¯ + NO<br />

Here are the two half-reactions to be combined:<br />

Here is the rule to follow:<br />

Ag+ + e¯ → Ag<br />

Cu → Cu 2+ + 2e¯<br />

the total electrons MUST cancel when the two half-reactions are added.<br />

Another way to say it:<br />

the number of electrons in each half-reaction MUST be equal when the two half-reactions are<br />

added.<br />

What that means is that one (or both) equations must be multiplied through by a factor. The value of<br />

the factor is selected so as to make the number of electrons equal.<br />

In our example problem, the top reaction (the one with silver) must be multiplied by two, like this:<br />

2Ag+ + 2e¯ → 2Ag<br />

168


Notice that each separate substance is increased by the factor amount. Occasionally, a student will<br />

multiply ONLY the electrons by the factor. That is incorrect.<br />

When the two half-reactions are added, we get:<br />

2Ag+ + 2e¯ + Cu → 2Ag + Cu 2+ + 2e¯<br />

With two electrons on each side, they may be canceled, resulting in:<br />

2Ag+ + Cu → 2Ag + Cu 2+<br />

This is the correct answer. Notice that there are two silvers on each side and one copper. Notice also<br />

that the total charge on each side is +2. It is balanced for both atoms and charge. Sometimes, I am<br />

asked if the order matters, if the Cu could be first on the left-hand side. The answer is that the order<br />

does not matter. There happen to be certain styles about where particular substances are put in the<br />

final answer, but these are only styles. They do not affect the chemical correctness of the answer.<br />

Notes:<br />

A half reaction is simply a reaction in which shows either reduction or oxidation, but not both. redox<br />

reactionare used in diffrent equation inorder o be balanced but not nesseraly the simple ones.<br />

Practice Problems<br />

Separate into half-reactions, balance them and then recombine.<br />

1) Sn + Cl2 ---> Sn 2+ + Cl¯<br />

2) Fe 2+ + I3¯ ---> Fe 3+ + I¯<br />

1. N in NO 3¯<br />

The O is -2 and three of them makes -6. Since -1 is left over, the N must be +5<br />

2. C in CO 3<br />

2¯<br />

The O is -2 and three of them makes -6. Since -2 is left over, the C must be +4<br />

3. Cr in CrO 4<br />

2¯<br />

The O is -2 and four of them makes -8. Since -2 is left over, the Cr must be +6<br />

4. Cr in Cr 2 O 7<br />

2¯<br />

The O is -2 and seven of them makes -14. Since -2 is left over, the two Cr must be +12<br />

What follows is an important point. Each Cr is +6. Each one. We do not speak of Cr 2 being +12. Each Cr atom is considered individually.<br />

5. Fe in Fe 2 O 3<br />

The O is -2 and three of them makes -6. Each Fe must then be +3<br />

6. +2 9. +7<br />

7. +5 10. +6<br />

8. +4<br />

1) Cl 2 + 2e¯ →2Cl¯ 5) ICl 2¯<br />

+ 2e¯ →I¯ + 2Cl¯<br />

2) Sn →Sn 2+ + 2e¯ 6) Sn →SnO 2 and NO 3¯<br />

→NO 2<br />

3) Fe 2+ →Fe 3+ + e¯ 7) HClO →Cl 2 and Co ---> Co 2+<br />

4) I 3¯ → 3I¯ + 2e¯ 8) NO 2 →NO 3¯<br />

and NO 2 →NO<br />

Note that in this last redox equation the NO 2 (actually just the N) is both being reduced AND being oxidized. In the first half-reaction, the N goes from +4<br />

to +5 (oxidation) and in the second, the N goes from +4 to +2 (reduction).<br />

By the way, we could flip the reaction so that NO 3¯<br />

and NO are reacting together to produce only one product, the NO 2 . In that case, the two halfreactions<br />

would be reversed.<br />

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