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<strong>Leonardo</strong> <strong>Alvarez</strong><br />
Chemistry<br />
Block 3
Converting Real Things<br />
Table 1<br />
Using the scale, come up with a conversion ratio just by looking at the scale and prove that it works<br />
but converting 10 grams to ounces. (Hint: 7grams and 15 grams)<br />
Table 2<br />
Using a 50 mL graduated cylinder, fill a 600mL beaker 66.7% full.<br />
Table 3<br />
Using the measuring cup determine how many mL are in 4 ounces of water. Make a conversion ratio<br />
you could use to do other conversions.<br />
Table 4<br />
Using a meter stick, measure the back table in inches, feet and yards and convert them into<br />
centimeters and meters.<br />
Table 5<br />
Using the scale, find the mass of a text book on your table in ounces (round to the nearest ounce)<br />
and cover it to grams.<br />
Table 6<br />
Using the ruler, measure the length of a piece of paper in inches and then convert that into meters.<br />
Make a conversion ratio you could use to do other conversions.
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.
1qt=32 oz 1gal = 4qts 1.00 qt = 946 mL 1L = 1000mL<br />
2. Convert 8135.6 mL to quarts<br />
=<br />
3. Convert 115.2 oz to mL<br />
=<br />
4. Convert 2.3 g to Liters<br />
=<br />
5. Convert 8.42 L to oz<br />
=<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 _________ to _________<br />
=<br />
2. Convert _________ to _________<br />
=<br />
3. Convert _________ to _________<br />
=<br />
4. Convert _________ to _________<br />
=<br />
5. Convert _________ to _________<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 b) 4 mL = ______L c) 8 g = _______mg<br />
d) 9 mg =_______g e) 2 mL = ______L f) 6 kg = _____g<br />
g) 4 cm =_______m h) 12 mg = ______ g i) 6.5 cm 3 = _______L<br />
j) 7.02 mL =_____cm 3 k) .03 hg = _______ dg l) 6035 mm _____cm<br />
m) .32 m = _______cm n) 38.2 g = _____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 />
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 />
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 />
5. Weather satellites orbit Earth at an altitude of 1,400,000 meters. What is this altitude in kilometers?<br />
6. Which unit would you use to measure the capacity? Write milliliter or liter.<br />
a) a bucket __________<br />
b) a thimble __________<br />
c) a water storage tank__________<br />
d) a carton of juice__________<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 />
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 />
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?
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 />
_____ 1. distance between two points<br />
a. time<br />
_____ 2. SI unit of length<br />
_____ 3. tool used to measure length<br />
_____ 4. units obtained by combining other units<br />
_____ 5. amount of space occupied by an object<br />
_____ 6. unit used to express volume<br />
_____ 7. SI unit of mass<br />
_____ 8. amount of matter in an object<br />
_____ 9. mass per unit of volume<br />
_____ 10. temperature scale of most laboratory thermometers<br />
_____ 11. instrument used to measure mass<br />
_____ 12. interval between two events<br />
_____ 13. SI unit of temperature<br />
_____ 14. SI unit of time<br />
_____ 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 />
________________________________________________________________________________<br />
17. balance, second, mass __________________________________________________________<br />
________________________________________________________________________________<br />
18. kilogram, liter, cubic centimeter __________________________________________________<br />
________________________________________________________________________________<br />
19. time, second, distance __________________________________________________________<br />
________________________________________________________________________________<br />
20. decimeter, kilometer, Kelvin _____________________________________________________<br />
________________________________________________________________________________
1. How many meters are in one kilometer? __________<br />
2. What part of a liter is one milliliter? __________<br />
3. How many grams are in two dekagrams? __________<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 />
5. What part of a meter is a decimeter? __________<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 ______________ .<br />
7. The system of measurement used worldwide in science is _______________ .<br />
8. SI is based on units of _______________ .<br />
9. The system of measurement that was based on units of ten was the _______________ system.<br />
10. In SI, _______________ 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 _______________ .
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 />
_____ a. kilometer<br />
_____ b. centimeter<br />
_____ c. meter<br />
_____ e. hectometer<br />
_____ f. millimeter<br />
_____ g. decimeter<br />
_____ 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 />
8. How many years make up a decade? _______________________________________________<br />
9. How many years make up a century? ______________________________________________<br />
10. What part of a second do you think a millisecond is? __________________________________
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.
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
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
Convert each number from Scientific Notation to real numbers:<br />
1. 7.485 X 10³ 6. 1.683 X 10⁰<br />
2. 8.842 X 10² 7. 3.622 10⁰<br />
3. 2.887 X 10−⁵ 8. 1.735 X 10−⁵<br />
4. 5.893 X 10−² 9. 9.736 X 10−¹<br />
5. 6.162 X 10−³ 10. 8.558 X 10−²<br />
Convert each number from a real number to Scientific Notation:<br />
11. 0.0006633 16. 1,937,000<br />
12. 0.0004445 17. 34,570<br />
13. 0.002182 18. 0.00003948<br />
14. 469.5 19. 894,500<br />
15. 727,400 20. 678.3
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.
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.
How Many Significant Digits for Each Number?<br />
1) 2359 = ______<br />
2) 2.445 x 10−⁵= ______<br />
3) 2.93 x 10⁴= ______<br />
4) 1.30 x 10−⁷= ______<br />
5) 2604 = ______<br />
6) 9160 = ______<br />
7) 0.0800 = ______<br />
8) 0.84 = ______<br />
9) 0.0080 = ______<br />
10) 0.00040 = ______<br />
11) 0.0520 = ______<br />
12) 0.060 = ______<br />
13) 6.90 x 10−¹= ______<br />
14) 7.200 x 10⁵= ______<br />
15) 5.566 x 10−²= ______<br />
16) 3.88 x 10⁸= ______<br />
17) 3004 = ______<br />
18) 0.021 = ______<br />
19) 240 = ______<br />
20) 500 = ______
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 = _______<br />
2) 87.54 - 3.3 = _______<br />
3) 99.1498 + 6.5397 + 9.7 = _______<br />
4) 5.868 - 5.1 = _______<br />
5) 59.9233 + 86.21 + 99.396 = _______<br />
6) 7.7 + 26.756 = _______<br />
7) 66.8 + 2.3 + 4.8516 = _______<br />
8) 9.7419 + 43.545 = _______<br />
9) 4.8976 + 48.4644 + 1.514 = _______<br />
10) 4.335 + 35.85 = _______<br />
11) 9.448 - 1.7 = _______<br />
12) 75.826 - 8.6555 = _______<br />
13) 57.2 + 23.814 = _______<br />
14) 77.684 - 4.394 = _______<br />
15) 26.4496 + 3.339 = _______<br />
16) 9.6848 + 29.85 = _______<br />
17) 63.11 + 2.5412 + 4.93 = _______<br />
18) 11.2471 + 75.4 = _______<br />
19) 73.745 - 8.755 = _______<br />
20) 6.5238 + 1.7 + 27.79 = _______
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 />
2) 720 ÷ 7.7 = __________<br />
3) 929 x 0.3 = __________<br />
4) 300 ÷ 44.31 = __________<br />
5) 608 ÷ 9.8 = __________<br />
6) 0.06 x 0.079 = __________<br />
7) 0.008 x 72.91 x 7000 = __________<br />
8) 73.94 x 67 x 780 = __________<br />
9) 0.62 x 0.097 x 40 = __________<br />
10) 600 x 10 x 5030 = __________<br />
11) 5200 ÷ 4.46 = __________<br />
12) 0.0052 x 0.4 x 107 = __________<br />
13) 0.099 x 8.8 = __________<br />
14) 0.0095 x 5.2 = __________<br />
15) 8000 ÷ 4.62 = __________<br />
16) 0.6 x 0.8 = __________<br />
17) 2.84 x 0.66 = __________<br />
18) 0.5 x 0.09 = __________<br />
19) 8100 ÷ 34.84 = __________<br />
20) 8.24 x 6.9 x 8100 = __________
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
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.
http://www.learner.org/interactives/periodic/basics_interactive.html
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.
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 (H 2 O), 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.
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.
P<br />
N<br />
P<br />
N
P<br />
N<br />
P<br />
N
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
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
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
In the space below, write the unabbreviated electron configurations of the following elements:<br />
1) sodium ________________________________________________<br />
2) iron ________________________________________________<br />
3) bromine ________________________________________________<br />
4) barium ________________________________________________<br />
5) neptunium ________________________________________________<br />
In the space below, write the abbreviated electron configurations of the following elements:<br />
6) cobalt ________________________________________________<br />
7) silver ________________________________________________<br />
8) tellurium ________________________________________________<br />
9) radium ________________________________________________<br />
10) lawrencium ________________________________________________<br />
Determine what elements are denoted by the following electron configurations:<br />
11) 1s²s²2p⁶3s²3p⁴ ____________________<br />
12) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s¹ ____________________<br />
13) [Kr] 5s²4d¹⁰5p³ ____________________<br />
14) [Xe] 6s²4f¹⁴5d⁶ ____________________<br />
15) [Rn] 7s²5f¹¹ ____________________<br />
Identify the element or determine that it is not a valid electron configuration:<br />
16) 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p⁵ ____________________<br />
17) 1s²2s²2p⁶3s³3d⁵ ____________________<br />
18) [Ra] 7s²5f⁸ ____________________<br />
19) [Kr] 5s²4d¹⁰5p⁵ ____________________<br />
20) [Xe] ____________________<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)
Using Wikipedia define the 8 categories of elements on pages 168 and 169 on the left<br />
page.<br />
Color your periodic table similar to the one on Pages 168—169.<br />
Alkali Metals -<br />
Alkali Earth Metals-<br />
Other Metals-<br />
Metalloids-<br />
Nonmetals-<br />
Noble Gases-<br />
Transions metals-<br />
Inner transion metals-
Atomic Size<br />
Increases<br />
Increases<br />
As you go from the top to boom of the energy level the energy levels of the elements increase<br />
As you go from le to right of the periodic table the mass increases which results in a bigger gravitaonal pull
Ionizaon Energy<br />
Increase<br />
Ionizaon energy is the energy needed to take away an electron away from<br />
an atom<br />
increase
Electronegavity<br />
increases<br />
Electronegavity is the ability for an atom to take an electron<br />
increases
Ion Size<br />
increase<br />
increase<br />
How they compare to atoms to ions<br />
Catons decrease in size because they giving up electrons and go down an energy level
Create groups for these Scientist and explain your groupings<br />
(use the information you got from your research)
Research these Scientist and summarize their contributions to chemistry<br />
Antoine Henri Becquerel<br />
Niels Bohr<br />
Louis de Barogilie<br />
Glenn Seaborg<br />
Hantaro Nagaoka<br />
Democritus<br />
Marie and Pierre Curie<br />
Eugene Goldstein<br />
Dmitri Mendeleev<br />
J.J. Thomson<br />
James Chadwick<br />
Erwin Shrodinger<br />
John Dalton<br />
Lothar Meyer<br />
Robert Millikan<br />
J.W. Dobereiner<br />
Ernest Rutherford
Nuclear radiation notes<br />
Chapter 25.1<br />
Block 3<br />
Leo <strong>Alvarez</strong><br />
25.1<br />
Radioactivity<br />
Atoms emit electromagnetic radiation when an electron moves from a higher energy level to a<br />
lower energy level<br />
Antoine made an accidental discovery by studying the ability of uranium salts that have been<br />
exposed to sunlight to fog photographic film plates<br />
In a chemical reaction atoms tend to attain more stable electron configuration by transferring or<br />
sharing electrons<br />
Radio active decay can be done without any input of energy<br />
Radiation is transmitted during radioactive decay<br />
Types of radiation<br />
Some radioactive sources emit helium nuclei and are also called alpha particles<br />
When an atom loses an alpha particle, the atomic number, the atomic number of the product is<br />
lower by two and its mass number is lowered by four
Radioisotopes can cause harm when ingested but do no harm in penetrating objects<br />
When a electron breaks apart from a neutron in an atom its called beta particle<br />
Beta particles are more penetrating than alpha particles are<br />
Gamma rays have no mass or electrical charge but are extremely penetrating<br />
25.2<br />
Nuclear stability and decay<br />
More than 1500 nuclei are known and only 264 are stable and do not decay<br />
When a nucleus is unstable it can undergo spontaneous decay for different reasons like having an<br />
unstable amount of neutrons relative to the number of protons<br />
A beta transmission is when a nucleus increases the amount of protons while decreasing the<br />
amount of neutrons<br />
Half life<br />
Every radioisotope is measured by its half life which is the time required for one half of<br />
the nuclei in a radioisotope sample to decay to products
Notes<br />
The students will learn how ionic compounds from and how metallic bonding affects the<br />
properties of metals<br />
Metals have several qualities that are unique, such as the ability to conduct electricity a low ionization<br />
energy, and a low electro-negativity<br />
Their physical properties include a lustrous (shiny) appearance, and they are malleable<br />
and ductile. Metals have a crystal structure.<br />
The strength of a metallic bond depends on three things:<br />
The number of electrons that become delocalized from the metal<br />
The charge of the cation (metal).<br />
The size of the cation.<br />
A strong metallic bond will be the result of more delocalized electrons<br />
Metallic bonds are strong and require a great deal of energy to break<br />
conduct-the action or manner of managing an activity or organization.<br />
delocalized- detach or remove (something) from a particular place or location, or from local limitations.<br />
ionization-the condition of being dissociated into ions (as by heat or radiation or chemical reaction or<br />
electrical discharge); "the ionization of a gas"<br />
Be 2 N 3-<br />
Mg 3 N 2<br />
magnesium nitride<br />
1-same<br />
2-di<br />
3-tri<br />
4-tetra
Metallic Character<br />
Metals have several qualities that are unique, such as the ability to conduct electricity, a low<br />
ionization energy, and a low electronegativity (so they will give up electrons easily, i.e., they are<br />
cations). Their physical properties include a lustrous (shiny) appearance, and they are malleable<br />
and ductile. Metals have a crystal structure.<br />
Metals that are malleable can be beaten into thin sheets, for example: aluminum foil.<br />
Metals that are ductile can be drawn into wires, for example: copper wire.<br />
Bonding Characteristics<br />
The strength of a metallic bond depends on three things:<br />
The number of electrons that become delocalized from the metal<br />
The charge of the cation (metal).<br />
The size of the cation.<br />
A strong metallic bond will be the result of more delocalized electrons, which causes the<br />
effective nuclear charge on electrons on the cation to increase, in effect making the size of the<br />
cation smaller. Metallic bonds are strong and require a great deal of energy to break, and<br />
therefore metals have high melting and boiling points.<br />
A metallic bonding theory must explain how so much bonding can occur with such few electrons<br />
(since metals are located on the left side of the periodic table and do not have many electrons in<br />
their valence shells). The theory must also account for all of a metal's unique chemical and<br />
physical properties.<br />
http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/General_Principles/Met<br />
allic_Bonding
Notes<br />
Metallic bonding constitutes the electrostatic attractive forces between the delocalized electrons.<br />
metallic bonding is sometimes compared with that of molten salts<br />
conduction electrons divide their density equally over all atoms that function as neutral<br />
Metallic bond is not the only type of chemical bonding a metal can exhibit, even as a simple substance<br />
gallium consists of covalently-bound pairs of atoms in both liquid and solid state—these pairs form a crystal<br />
lattice with metallic bonding between them.<br />
gallium-the chemical element of atomic number 31, a soft silvery-white metal that melts at about 30°C, just above<br />
room temperature.<br />
lattice-the structure of fissionable and non-fissionable materials geometrically arranged within a nuclear reactor.<br />
electrostatic force- the electrostatic interaction between electrically charged particles.
Metallic bonding constitutes the electrostatic attractive forces between the delocalized electrons,<br />
called conduction electrons, gathered in an electron cloud and the positively charged metal ions.<br />
Understood as the sharing of "free" electrons among a lattice of positively charged ions (cations),<br />
metallic bonding is sometimes compared with that of molten salts; however, this simplistic<br />
view[which?] holds true for very few[which?] metals. In a more quantum-mechanical view, the<br />
conduction electrons divide their density equally over all atoms that function as neutral (noncharged)<br />
entities.[citation needed] Metallic bonding accounts for many physical properties of<br />
metals, such as strength, malleability, ductility, thermal and electrical conductivity, opacity, and<br />
luster.[1][2][3][4]<br />
Although the term "metallic bond" is often used in contrast to the term "covalent bond", it is<br />
preferable[by whom?] to use the term metallic bonding, because this type of bonding is<br />
collective in nature and a single "metallic bond" does not exist. Metallic bond is not the only type<br />
of chemical bonding a metal can exhibit, even as a simple substance. For example, elemental<br />
gallium consists of covalently-bound pairs of atoms in both liquid and solid state—these pairs<br />
form a crystal lattice with metallic bonding between them. Another example of a metal–metal<br />
covalent bond is mercurous ion (Hg2+<br />
2).<br />
http://en.wikipedia.org/wiki/Metallic_bond
Ionic bonds<br />
Metal + non metals<br />
Cations + Anion<br />
Cation Non metal (metal)<br />
NaCl= Sodium Chloride = Na Cl<br />
Be F = Beryllium Floride = BeF2<br />
Formula unit is used to show how any electrons the atom will have<br />
Coveland Bond atoms<br />
Sharing electrons<br />
H20<br />
The bigger the mass of an atom, the more electrons it will take<br />
H202 + dihydrogen<br />
Oxygen (O) can disappear sometimes (99 percent of the time)
PCl3<br />
Phosphurus Triclohride\<br />
SBr2
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-
Orbital Equation Lone Pairs Angle Name
www.youtube.com/watch?v=AsqEkF7hcII<br />
www.youtube.com/watch?v=tEn0N4R2dqA<br />
www.youtube.com/watch?v=Pft2CASl0M0<br />
www.youtube.com/watch?v=rwhJklbK8R0<br />
The Mole
www.youtube.com/watch?v=BTRm8PwcZ3U<br />
www.youtube.com/watch?v=F9NkYSKJifs<br />
www.youtube.com/watch?v=xPdqEX_WMjo<br />
Molar Mass
Mole Conversions
Steps for Mole Conversions
Answer the following questions:<br />
1) How many moles are in 25 grams of water?<br />
Mole Calculation Practice<br />
2) How many grams are in 4.5 moles of Li 2 O?<br />
3) How many molecules are in 23 moles of oxygen?<br />
4) How many moles are in 3.4 x 10 23 molecules of H 2 SO 4 ?<br />
5) How many molecules are in 25 grams of NH 3 ?<br />
6) How many grams are in 8.2 x 10 22 molecules of N 2 I 6 ?
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 />
C 3 H 8 + O 2 --> H 2 O + CO 2<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 />
Right side: 1 carbon, 2 hydrogen and 3 oxygen
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 />
C 3 H 8 + O 2 --> H 2 O + 3CO 2<br />
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.
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 />
C 3 H 8 + O 2 --> 4H 2 O + 3CO 2<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 />
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 />
C 3 H 8 + 5O 2 --> 4H 2 O + 3CO 2.<br />
The carbon, hydrogen and oxygen atoms are balanced. Your equation is complete.
1) ___ NaNO 3 + ___ PbO ___ Pb(NO 3 ) 2 + ___ Na 2 O<br />
2) ___ AgI + ___ Fe 2 (CO 3 ) 3 ___ FeI 3 + ___ Ag 2 CO 3<br />
3) ___ C 2 H 4 O 2 + ___ O 2 ___ CO 2 + ___ H 2 O<br />
4) ___ ZnSO 4 + ___ Li 2 CO 3 ___ ZnCO 3 + ___ Li 2 SO 4<br />
5) ___ V 2 O 5 + ___ CaS ___ CaO + ___ V 2 S 5
6) ___ Mn(NO 2 ) 2 + ___ BeCl 2 ___ Be(NO 2 ) 2 + ___ MnCl 2<br />
7) ___ AgBr + ___ GaPO 4 ___ Ag 3 PO 4 + ___ GaBr 3<br />
8) ___ H 2 SO 4 + ___ B(OH) 3 __ B 2 (SO 4 ) 3 + ___ H 2 O<br />
9) ___ S 8 + ___ O 2 ___ SO 2<br />
10) ___ Fe + ___ AgNO 3 ___ Fe(NO 3 ) 2 + ___ Ag
1) 2 NaNO 3 + PbO Pb(NO 3 ) 2 + Na 2 O<br />
2) 6 AgI + Fe 2 (CO 3 ) 3 2 FeI 3 + 3 Ag 2 CO 3<br />
3) C 2 H 4 O 2 + 2 O 2 2 CO 2 + 2 H 2 O<br />
4) ZnSO 4 + Li 2 CO 3 ZnCO 3 + Li 2 SO 4<br />
5) V 2 O 5 + 5 CaS 5 CaO + V 2 S 5<br />
6) Mn(NO 2 ) 2 + BeCl 2 Be(NO 2 ) 2 + MnCl 2<br />
7) 3 AgBr + GaPO 4 Ag 3 PO 4 + GaBr 3<br />
8) 3 H 2 SO 4 + 2 B(OH) 3 B 2 (SO 4 ) 3 + 6 H 2 O<br />
9) S 8 + 8 O 2 8 SO 2<br />
10) Fe + 2 AgNO 3 Fe(NO 3 ) 2 + 2 Ag<br />
Additional Notes:
Categories of 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 />
A + BC ---> AC + B<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<br />
and 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 ---> H 2O + BA<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 />
C 10H 8 + 12 O 2 ---> 10 CO 2 + 4 H 2O<br />
If something that has carbon and hydrogen reacts with oxygen, it’s probably a combustion reaction.<br />
The products will be CO 2 and H 2 O.<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 it's<br />
a synthesis reaction<br />
2) Does your reaction have one large molecule falling apart to make several small ones? If yes, then<br />
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.
1) NaOH + KNO 3 --> NaNO 3 + KOH<br />
2) CH 4 + 2 O 2 --> CO 2 + 2 H 2 O<br />
3) 2 Fe + 6 NaBr --> 2 FeBr 3 + 6 Na<br />
List what type the following reactions are:<br />
4) CaSO 4 + Mg(OH) 2 --> Ca(OH) 2 + MgSO 4<br />
5) NH 4 OH + HBr --> H 2 O + NH 4 Br<br />
6) Pb + O 2 --> PbO 2<br />
7) Na 2 CO 3 --> Na 2 O + CO 2<br />
Predicting Reaction Products<br />
Predict the products of each of the following chemical reactions. If a reaction will not occur, explain<br />
why not:<br />
Category of Reaction<br />
1) __Ag 2 SO 4 + __NaNO 3 →<br />
2) __NaI + __CaSO 4 →<br />
3) __HNO 3 + __Ca(OH) 2 →<br />
4) __CaCO 3 →<br />
5) __AlCl 3 + __(NH 4 )PO 4 →<br />
6) __Pb + __Fe(NO 3 ) 3 →<br />
7) __C 3 H 6 + __O 2 →<br />
8) __Na + __CaSO 4 →<br />
__________________<br />
__________________<br />
__________________<br />
__________________<br />
__________________<br />
__________________<br />
__________________<br />
__________________
1) double displacement<br />
2) combustion<br />
3) single displacement<br />
4) double displacement<br />
5) acid-base<br />
6) synthesis<br />
7) decomposition<br />
List what type the following reactions are: (answers)<br />
Predicting Reaction Products – Answers<br />
Predict the products of each of the following chemical reactions. If a reaction will not occur, explain why not:<br />
1) ____ Ag 2 SO 4 + ____ NaNO 3 → no reaction!<br />
Examining this reaction, it appears that a double displacement reaction will occur. This would lead to the conclusion that<br />
the products would be AgNO3 and Na2SO4. However, for this reaction to occur, both reactants and only one of the<br />
products must be soluble in water. If you look up the solubilities on a chart, you’ll find that Ag2SO3 is partly soluble in<br />
water, and all of the other compounds are totally soluble in water. This tells us that this reaction will not occur.<br />
2) ____ NaI + ____ CaSO 4 → no reaction!<br />
Another double displacement reaction, this time with Na2SO4 and CaI2 as products. Because both products are soluble<br />
in water and CaSO4 is only partially soluble in water, the conditions for a successful double displacement reaction are not<br />
met.<br />
3) 2 HNO 3 + 1 Ca(OH) 2 → 1 Ca(NO 3 ) 2 + 2 H 2 O<br />
It’s an acid-base reaction, and acid-base reactions occur readily whether or not the reactants are both soluble in water.<br />
4) 1 CaCO 3 → 1 CaO + 1 CO 2<br />
It’s a decomposition reaction. If you didn’t guess that these were the products, you should have at least known that it was<br />
a decomposition reaction and predicted that this would have broken into its constituent elements, Ca, C, and O2.<br />
5) 1 AlCl 3 (aq) + 1 (NH 4 ) 3 PO4(aq) → AlPO 4 (s) + 3 NH 4 Cl(aq)<br />
This is a double displacement reaction, except in this case both of the reactants and only one product are soluble in<br />
water. Because the conditions for a successful reaction are met, the reaction does occur!<br />
6) ____ Pb + ____ Fe(NO 3 ) 3 →<br />
Though this is a single displacement reaction, lead is lower on the activity series than the iron it would replace. As a<br />
result, this reaction does not occur.<br />
7) 2 C 3 H 6 + 9 O 2 → 6 CO 2 + 6 H 2 O<br />
The reactants suggest that this is a combustion reaction, meaning that the products must be carbon dioxide and water.<br />
Once you figure this out, the only thing left to do is balance it, as shown.<br />
8) 2 Na + 1 CaSO 4 → 1 Na 2 SO 4 + 1 Ca<br />
This should clearly be a single displacement reaction. Because sodium is higher on the activity series than calcium, this<br />
reaction does occur.
Balancing Equations Practice Problems<br />
From Widener Chemistry Practice<br />
1 page<br />
The students will learn how balanced chemical equations are used in stoichiometric calculations and<br />
how to calculate amounts of reactants and products in a chemical equation.
Stoichiometry Practice Problems<br />
From Widener Chemistry Practice<br />
2 pages<br />
The students will learn how balanced chemical equations are used in stoichiometric calculations and<br />
how to calculate amounts of reactants and products in a chemical equation.
Percent Yield Practice Problems<br />
from Widener Chemistry Practice<br />
1 pages<br />
The students will learn how balanced chemical equations are used in stoichiometric calculations and<br />
how to calculate amounts of reactants and products in a chemical equation.
Learning goal: the students will learn what are the factors that determine and<br />
characteristics that distinguish gases, liquids and solids and how substances change<br />
from one state to another<br />
Gas<br />
The particles in a gas are usually molecules or atoms, they are considered to be small, hard<br />
spheres with an insignificant volume. Between the particles there is empty space no<br />
attractive or repulsive forces exists between the particles. The motion of the particles in a<br />
gas is rapid, constant and random. Gases fill their containers regardless of the shape and<br />
volume. The particles travel in a straight line until they collide with another object.<br />
Gas pressure results from the force exerted by a gas per unit surface area of an object. It is<br />
the result of billions of rapidly moving particles in a gas simultaneously colliding with an<br />
object. The collisions of atoms and molecules in air with objects results in atmospheric<br />
pressure. It decreases when you climb a mountain because earths atmosphere decreases as<br />
the elevation increases.<br />
The average speed of oxygen molecules in air at 20 C is 1700 km/h. At these high speed the<br />
odor from a pizza in Washington D.C, should reach Mexico city in about 115 minutes. This<br />
does not happen because the molecules responsible for the odor are constantly striking<br />
molecules in air and rebounding in other directions. The aimless path the molecules take is<br />
called a random walk.
Liquids<br />
Both the particles in gases and the particles in liquids have kinetic energy. This energy allows<br />
the particles in gases and liquids to flow past one another. The ability of gases and liquids to<br />
flow allows them to conform to the shape of their containers. There are no attractions<br />
between the particles in a gas. The particles in a liquid are attracted to each other, these<br />
intermolecular attractions keep the particles in a liquid close together.<br />
The interplay between the disruptive motions of particles in a liquid and the attractions<br />
among the particles determines the physical properties of a liquid. Intermolecular<br />
attractions reduce the amount of space between the particles in a liquid. Increasing the<br />
pressure of a liquid has hardly any effect on its volume as well as solids. Therefore, liquids<br />
and solids are known as condensed states of matter.<br />
The conversion occurs of a liquid to a gas or vapor is called vaporization. When the<br />
conversion occurs at a surface of a liquid that is not boiling is called evaporation. During<br />
evaporation , only those molecules with a certain minimum kinetic energy can escape<br />
from the surface of a liquid. The rate of evaporation of a liquid from an open container<br />
increases as the liquid is heated. Heating allows a greater number of particles at the<br />
liquids surface to overcome the attractive forces that keep the liquid in state.
Solid<br />
The general properties of solids reflect the orderly arrangement of their particles and the<br />
fixed locations of their particle. In most solids, the atoms, ions, or molecules are packed<br />
tightly together. These solids are dense and not easy to compress because the particles in<br />
solids tend to vibrate about fixed points, solids do not flow.
Iliana Gonzalez, Gaby Cordon, Leo <strong>Alvarez</strong>, Eddy Isaac
Boyle’s Law<br />
• As volume decreases, Pressure<br />
increases when the temperature stays<br />
the same
Where:<br />
P1 = initial pressure<br />
V1 = initial volume<br />
P2 = final pressure<br />
V2 = final volume<br />
Boyle’s Formula<br />
P1* V1= P2* V2<br />
EXAMPLE:<br />
P1=105 kpa<br />
V1= 2.50 L<br />
P2= 40.5 kpa<br />
V2= ?<br />
105 kpa x 2.50 kpa = 6.48 L<br />
40.5 kpa
http://www.youtube.com/watch?v=27yqJ9vJ5kQ
Charles’ Law<br />
• Volume increases/decreases as<br />
temperature increases/decreases if<br />
the pressure stays the same
Where:<br />
V1 = initial volume<br />
T1 = initial temperature<br />
V2= final volume<br />
T2= final temperature<br />
Charles’ Formula<br />
V1/T1= V2/ T2<br />
EXAMPLE:<br />
V1 = 6.80 L<br />
T1 = 325 ◦C<br />
V2= ?<br />
T2= 25◦C<br />
6.80 L x 25◦C = .523 L<br />
325 ◦C
http://www.youtube.com/watch?v=7JKVtbe-hV8
Gay-Lussac’s Law<br />
• When one connected value goes up<br />
so does the other, meaning that if the<br />
volume stays the same the<br />
temperature increases with pressure.
Gay-Lussac’s Formula<br />
P1/T1= P2/ T2<br />
Where:<br />
P1 = initial pressure<br />
T1 = initial temperature<br />
P2= final pressure<br />
T2= final temperature<br />
EXAMPLE:<br />
P1 = 108 L<br />
T1 = 41 ◦C<br />
P2= ?<br />
T2= 22◦C<br />
108 kpa x 22◦C = .57.9 kpa<br />
41 ◦C
DEMONSTRATION<br />
GAY-LUSSAC’S LAW<br />
WATCH AND LEARN<br />
http://www.youtube.com/watch?v=j1yFvlgHM9Y
Unit 5 & 6 Test Review<br />
Heat of Fusion<br />
q = m ∙ΔH f<br />
Specific Heat<br />
c = ____q____<br />
m ∙ ΔT ᵒC<br />
Heat of Fusion of Water<br />
334 J/g = 80 cal/g<br />
Specific Heat of Water<br />
4.18 J/g ∙ᵒC<br />
Heat of fusion is the amount of heat energy required to change the state of a substance from solid to<br />
liquid. This example problem demonstrates how to calculate the amount of energy required to melt a<br />
sample of water ice.<br />
With Graham's Law, you can find the effusion rates for two gases or the molecular mass of a gas.<br />
This ratio of effusion rates follows the pattern that the gas with the lesser molecular mass has a<br />
greater rate of effusion.<br />
Ideal Gas Law<br />
Combined Gas Law<br />
p∙v=n∙R∙T V 1 ∙P 1 = V 2 ∙P 2<br />
T 1 T 2<br />
R = .082 atm or 8.31kpa<br />
Boyle’s Law<br />
P 1 ∙V 1 = P 2 ∙V 2<br />
Charles’ Law<br />
Gay – Lussac’s Law<br />
V 1 = V 2 P 1 = P 2<br />
T 1 T 2 T 1 T 2<br />
Molarity<br />
M = moles<br />
L<br />
Gas Solubility<br />
S 1 = S 2<br />
P 1 P 2
Unit 5<br />
Chapter 13 States of Matter<br />
Chapter 14 The Behavior of Gases<br />
Chapter 15 Water and Aqueous Systems<br />
Unit 6<br />
Chapter 16 Solutions<br />
Chapter 17 Thermochemistry<br />
Chapter 18 Reaction Rates and Equilibrium<br />
Chapter 19 Acid and Bases<br />
Learning Goals<br />
The students will learn what are the factors that determine and characteristics that distinguish gases<br />
liquids and solids and how substances change from one state to another.<br />
The students will learn how gases respond to changes in pressure, volume, and temperature and why<br />
the ideal gas law is useful even though ideal gases do not exist.<br />
The students will learn how the interactions between water molecules account for the unique<br />
properties of water and how aqueous solutions form.<br />
The student will learn how energy is converted in a chemical or physical process and how to<br />
determine the amount of energy is absorbed or released in that process.