1. Given the balanced equation - Revsworld

1. Given the balanced equation:
2Na + S → Na 2 S
What is the total number of moles of S that reacted when
4.0 moles of Na were completely consumed?
1) 1.0 mole 3) 0.5 mole
2) 2.0 moles 4) 4.0 moles
2. Given the reaction:
N 2 (g) + 3H 2 (g) → 2NH 3 (g)
What is the total number of moles of NH 3 (g) produced
when 10. moles of H 2 (g) reacts completely with N 2 (g)?
1) 6.7 3) 3.0
2) 2.0 4) 15
3. Given the balanced equation:
2 C 4 H 10 (g) + 13 O 2 (g) → 8 CO 2 (g) + 10 H 2 O(g)
What is the total number of moles of O 2 (g) that must
react completely with 5.00 moles of C 4 H 10 (g)?
1) 10.0 3) 26.5
2) 20.0 4) 32.5
4. Given the reaction:
Ca + 2H 2 O → Ca(OH) 2 + H 2
How many moles of H 2 O are needed to exactly react
with 2.0 moles of Ca?
1) 1.0 3) 0.50
2) 2.0 4) 4.0
5. Given the reaction:
PbCl 2 (aq) + Na 2 CrO 4 (aq) →
PbCrO 4 (s) + 2 NaCl(aq)
What is the total number of moles of NaCl formed when
2 moles of Na 2 CrO 4 react completely?
1) 1 mole 3) 3 moles
2) 2 moles 4) 4 moles
6. Given the equation:
Zn + 2HCl → ZnCl 2 + H 2
How many moles of HCl would be required to produce a
total of 2 moles of H 2 ?
1) 0.5 3) 3
2) 2 4) 4
7. Given the reaction:
2Na + 2H 2 O → 2NaOH + H 2
What is the total number of moles of hydrogen produced
when 4 moles of sodium react completely?
1) 1 3) 3
2) 2 4) 4
8. Given the reaction:
6 CO 2 + 6 H 2 O →C 6 H 12 O 6 + 6 O 2
What is the total number of moles of water needed to
make 2.5 moles of C 6 H 12 O 6 ?
1) 2.5 3) 12
2) 6.0 4) 15
9. Given the equation:
2 C 2 H 2 (g) + 5 O 2 (g) - 4 CO 2 (g) + 2 H 2 O(g)
How many moles of oxygen are required to react
completely with 1.0 mole of C 2 H 2 ?
1) 2.5 3) 5.0
2) 2.0 4) 10
10. Given the equation:
2C 4 H 10 + 13O 2 → 8CO 2 + 10H 2 O
How many moles of carbon dioxide are produced for
each mole of butane consumed?
1) 1 3) 8
2) 2 4) 4
11. Given the reaction:
4Al(s) + 3O 2 (g) → 2Al 2 O 3 (s)
What is the minimum number of grams of oxygen gas
required to produce 1.00 mole of aluminum oxide?
1) 32.0 g 3) 96.0 g
2) 48.0 g 4) 192 g
12. In the reaction
Fe 2 O 3 + 3CO → 2Fe + 3CO 2 ,
what is the total number of moles of CO used to produce
112 grams of iron?
1) 1.0 3) 3.0
2) 2.0 4) 4.0
13. Given the balanced equation:
Fe(s) + CuSO 4 (aq) - FeSO 4 (aq) + Cu(s) What
total mass of iron is necessary to produce 1.00 mole of
copper?
1) 26.0 g 3) 112 g
2) 55.8 g 4) 192 g
14. According to the reaction
H 2 + Cl 2 → 2HCl,
the production of 2.0 moles of HCl would require 70.
grams of Cl 2 and
1) 1.0 g of H 2
2) 2.0 g of H 2
3) 3.0 g of H 2
4) 4.0 g of H 2
15. Given the balanced equation:
NaOH + HCl → NaCl + H 2 O
What is the total number of grams of H 2 O produced
when 116 grams of the product, NaCl, is formed?
1) 9.0 g 3) 36 g
2) 18 g 4) 54 g
16. Given the reaction:
4Al + 3O 2 → 2Al 2 O 3
How many moles of Al 2 O 3 will be formed when 27
grams of Al reacts completely with O 2 ?
1) 1.0 3) 0.50
2) 2.0 4) 4.0

17. Given the reaction:
2C 2 H 6 + 7O 2 → 4CO 2 + 6H 2 O
What is the total number of CO 2 molecules produced
when one mole of C 2 H 6 is consumed?
1) 6.02 × 10 23 3) 3(6.02 × 10 23 )
2) 2(6.02 × 10 23 ) 4) 4(6.02 × 10 23 )
18. In a laboratory experiment, a student reacted 2.8 grams
of Fe(s) (steel wool) in excess CuSO 4 (aq), according to
the following balanced equation:
Fe(s) + CuSO 4 (aq) → FeSO 4 (aq) + Cu(s)
When the Fe(s) was completely consumed, the
precipitated Cu(s) had a mass of 3.2 grams. Did the
student's result in this experiment verify the mole ratio of
Fe(s) to Cu(s) as predicted by the equation?
1) Yes, because the experimental result was 2:1.
2) No, because the experimental result was 2:1.
3) Yes, because the experimental result was 1:1.
4) No, because the experimental result was 1:1.
19. Given the reaction:
Cu + 4HNO 3 → Cu(NO 3 ) 2 + 2H 2 O + 2NO 2
What is the total mass of H 2 O produced when 32 grams
of Cu is completely consumed?
1) 9.0 g 3) 36 g
2) 18 g 4) 72 g
20. Given the reaction:
N 2 + 3H 2 → 2NH 3
How many grams of ammonia are produced when 1.0
mole of nitrogen reacts?
1) 8.5 3) 34
2) 17 4) 68
21. Magnesium was reacted with an excess of dilute
hydrochloric acid and the hydrogen gas produced
collected in a eudiometer. The volume of hydrogen in the
eudiometer was corrected to conditions of STP. If 94.1
milliliters of hydrogen was produced, how much
magnesium reacted in this experiment?
1) 0.01 g 3) 0.05 g
2) 0.10 g 4) 0.50 g
22. Given the equation:
6CO 2 (g) + 6H 2 O(l) → C 6 H 12 O 6 (s) + 6O 2 (g)
What is the minimum number of liters of CO 2 (g),
measured at STP, needed to produce 32.0 grams of
oxygen?
1) 264 L 3) 192 L
2) 32.0 L 4) 22.4 L
23. Given the reaction:
Mg + H 2 SO 4 → MgSO 4 + H 2
How many grams of H 2 SO 4 are needed to produce
exactly 11.2 liters of H 2 , measured at STP?
1) 24.5 3) 98.0
2) 49.0 4) 196
24. Given the reaction
N 2 (g) + 3H 2 (g) → 2NH 3 (g)
How many liters of ammonia, measured at STP, are
produced when 28.0 grams of nitrogen is completely
consumed?
1) 5.60 3) 22.4
2) 11.2 4) 44.8

25. In a laboratory experiment, a student determined the mass of the product, KClO 3 (s), to be 45.7 grams.
a. Calculate the gram formula mass of KClO 3 (s). Round atomic masses from the Periodic Table to the nearest tenth. [Show all
work. Indicate the correct answer in proper significant figures and include an appropriate unit.]
b. Calculate the number of moles of KClO 3 (s) produced. [Show all work. Indicate the correct answer in proper significant figures.]
26. Given the unbalanced equation:
__Al 2 (SO 4 ) 3 + __Ca(OH) 2 → __Al(OH) 3 + __CaSO 4
Balance the equation using smallest whole number
coefficients.
27. Base your answer to the following question on the unbalanced equation provided:
___ C 5 H 12 (g) + ___ O 2 (g) → ___ CO 2 (g) + ___ H 2 O(g)
Balance the equation using the smallest whole-number coefficients.
28. Given the compound C 4 H 10 O 8,
a Calculate the molar masss of the compound.
b
c
Calculate the number of moles in 17.7 grams of the compound.
What is the empirical formula for this compound?
29. Base your answer to the following question on the information and equation below.
Antacids can be used to neutralize excess stomach acid. Brand Aantacid contains the acid-neutralizing agent magnesium
hydroxide, Mg(OH) 2 . It reacts with HCl(aq) in the stomach, according to the following balanced equation:
2 HCl(aq) + Mg(OH) 2 (s) → MgCl 2 (aq) + 2 H 2 O(…)
If a person produces 0.050 mole of excess HCl in the stomach, how many moles of Mg(OH) 2 are needed to neutralize this excess
hydrochloric acid?
30. Base your answer to the following question on the balanced chemical equation below.
2 H 2 O → 2 H 2 + O 2
How does the balanced chemical equation show the Law of Conservation of Mass?
31. A student heats a 243 gram sample of BaCl 2 • 2H 2 O hydrated crystals?
a What was the percentage by mass of water in the hydrated crystals?[Show all work]
b If all the water was driven out of the crystal, what would be the expected weight of the BaCl 2 sample remaining?[Show all work]

32. Base your answer to the following question on the
information below, which describes the smelting of iron
ore, and on your knowledge of chemistry.
In the smelting of iron ore, Fe 2 O 3 is reduced in a blast
furnace at high temperature by a reaction with carbon
monoxide. Crushed limestone, CaCO 3 , is also added to
the mixture to remove impurities in the ore. The carbon
monoxide is formed by the oxidation of carbon(coke), as
shown in the reaction below:
2 C + O2 - 2 CO + energy
Liquid iron flows from the bottom of the blast furnace
and is processed into different alloys of iron.
Balance the equation for the reaction of Fe 2 O 3 and CO
using the smallest whole-number coefficients.
Base your answers to questions 33 and 34 on the particle diagrams below, which show atoms and/or molecules in three different samples of
matter at STP.
33. Which sample represents a pure substance?
34. Explain why (x)(x) does not represent a compound.

35. The following procedures are carried out during a laboratory activity to determine the mass in grams of CuSO 4 in a hydrated sample
of CuSO 4 •5H 2 O.
Step 1 Determine the mass in grams of the crucible and CuSO 4 •5H 2 O.
Step 2 Determine the mass in grams of the crucible and CuSO 4
Step 3 Determine the mass in grams of CuSO 4 •5H 2 O.
Step 4 Determine the mass in grams of the empty crucible.
Step 5 Determine the mass in grams of CuSO 4
Arrange the steps above in the order that the student should use to determine the mass of CuSO 4 in the sample.
_______, _______, _______, _______, ________
36. Base your answers to the following questions on the information below.
For health reasons, the element chlorine is added to the drinking water because it will kill disease-causing
organisms. Typically 0.50 ppm of chlorine is added to drinking water to make it safe.
In 2.0 liters of drinking water (2000.g), how many grams of chlorine is present?[Show all work. Include in your answer proper
units and significant figures.]
37. In a laboratory experiment, a student determined the mass of the product, CaSO 4 (s), to be 31.9 grams.
a Calculate the gram formula mass of CaSO 4 (s). Round atomic masses from the Periodic Table to the nearest tenth. [Show all
work. Indicate the correct answer in proper significant figures and include an appropriate unit.]
b Calculate the number of moles of CaSO 4 (s) produced. [Show all work.
Indicate the correct answer in proper significant figures.]
38. In a laboratory experiment, a student determined the mass of the product, NaCl(s), to be 1.84 grams.
a Calculate the gram formula mass of NaCl(s). Round atomic masses from the Periodic Table to the nearest tenth. [Show all work.
Indicate the correct answer, including an appropriate unit.]
b Calculate the number of moles of NaCl(s) produced. Show all work. Indicate the correct answer.
39. Given the unbalanced equation:
__NH 3 + __O 2 → __HNO 3 + __ H 2 O
balance the equation using the smallest whole number
coefficients.

40. In a laboratory experiment, a student determined the mass of the product, HgBr(s), to be 98.7 grams.
a Calculate the gram formula mass of HgBr(s). Round atomic masses from the Periodic Table to the nearest tenth. [Show all work.
Indicate the correct answer in proper significant figures and include an appropriate unit.]
b Calculate the number of moles of HgBr(s) produced. [ Show all work. Indicate the correct answer in proper significant figures.]
41. Given the unbalanced equation:
__Li + __N 2 → __Li 3 N
balance the equation using smallest whole number
coefficients.
42. Base your answers to the following questions on the information below.
Rockets use as fuel, liquid hydrogen, H 2 (l) and liquid oxygen , O 2 (l) , which react together forming hot gaseous
water. This reaction provides the energy to lift the the shuttle and it's crew.
Write a balanced equation for the reaction of liquid hydrogen with liquid oxygen to produce gaseous water. Include the energy term
( " + energy" ) in your equation.
43. In a laboratory experiment, a student determined the mass of the product, LiCl(s), to be 0.333 grams.
a Calculate the gram formula mass of LiCl(s). Round atomic masses from the Periodic Table to the nearest tenth. [Show all work.
Indicate the correct answer in proper significant figures and include an appropriate unit.]
b Calculate the number of moles of LiCl(s) produced. [Show all work. Indicate the correct answer in proper significant figures.]
44. In a laboratory experiment, a student determined the mass of the product, NaNO 3 (s), to be 0.105 grams.
a. Calculate the gram formula mass of NaNO 3 (s). Round atomic masses from the Periodic Table to the nearest tenth. [ Show all
work. Indicate the correct answer in proper significant figures and include an appropriate unit.]
b. Calculate the number of moles of NaNO 3 (s) produced. [Show all work. Indicate the correct answer in proper significant figures.]

Reference Tables

Answer Key
1. 2
29. 0.025
2. 1
3. 4
30. Acceptable responses: 4 H and 2 O on both sides; 4 H = 4 H
and 2 O = 2 O; same number of each element on both sides.
4. 4
31. a) 36/ (137 + 71 + 36) × 100 = 15% b) 207 grams
5. 4
32. 1 Fe 2 O 3 + 3 CO - 2 Fe + 3 CO 2
6. 4
33. Allow credit for 3.
7. 2
34. Acceptable responses: A compound must contain two or more
8. 4
different elements, only 1 kind of atom present.
9. 1
35. 4,1,3,2,5
36. 0.0010 g
10. 4
37. a) 40.1 + 32.1 + 4(16.0) = 136.2 g b) 31.9g x 1.00
11. 2
mole/136.2g = 0.234 mole
12. 3
38. a) 23.0 + 35.5 = 58.5 g b) 1.84 g × 1.00 mole/58.5 g =
0.0315 mole
13. 2
39. 1 NH 3 + 2 O 2 → 1 HNO 3 + 1 H 2 O
14. 2
40. a) 200.6 + 79.9 = 280.5g b) 98.7g × 1.00 mole/280.5g =
15. 3
0.352 mole
16. 3
41. _6_Li + _1_N 2 → _2_Li 3 N
17. 2
42. 2 H 2 (l) + O 2 (l) → 2 H 2 O(g) + energy
18. 3
43. a) 6.9 + 35.5 = 42.4g b) 0.333g × 1.00 mole/42.4g =
0.00785 mole
19. 2
44. a) 23.0 + 14.0 + 3(16.0) = 85.0 g b) 0.105g x 1.00
20. 3
mole/85.0g = 0.00124 mole
21. 2
22. 4
23. 2
24. 4
25. a) 39.1 + 35.5 + 3(16.0) = 122.6 g b) 45.7g x 1.00
mole/122.6g = .373 mole
26. _1_Al 2 (SO 4 ) 3 + _3_Ca(OH) 2 → _2_Al(OH) 3 + _3_CaSO 4
27. Allow credit for C 5 H 12 (g) + 8 O 2 (g) → 5 CO 2 (g) + 6 H 2 O(g).
Allow credit even if the coefficient “1” is written in front of C 5 H 12
(g)