Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) When the following equation is balanced, the coefficients are __________.
1)
C8H18 + O2 → CO2 + H2O
A) 2, 3, 4, 4
B) 2, 25, 16, 18
C) 2, 12, 8, 9
D) 4, 4, 32, 36
E) 1, 4, 8, 9
2)
2) Of the reactions below, which one is a decomposition reaction?
A) 2Mg + O2 → 2MgO
B) 2N2 + 3H2 → 2NH3
C) 2CH4 + 4O2 → 2CO2 + 4H2O
D) NH4Cl → NH3 + HCl
E) Cd(NO3)2 + Na2S → CdS + 2NaNO3
3) Which one of the following is not true concerning automotive air bags?
A) A gas is produced when the air bag activates.
B) The gas used for inflating them is oxygen
C) They are loaded with sodium azide initially
D) The two products of the decomposition reaction are sodium and nitrogen
E) They are inflated as a result of a decomposition reaction
3)
4) Calculate the percentage by mass of chlorine in PtCl2(NH3)2.
4)
A) 11.82
B) 23.63
C) 25.05
D) 18.09
E) 12.53
5)
5) There are __________ atoms of oxygen are in 300 molecules of CH3CO2H.
A) 3.01 × 1024
B) 1.80 × 1026
C) 600
D) 300
E) 3.61 × 1026
6) How many grams of hydrogen are in 23 g of CH4O?
A) 4.0
B) 5.8
C) 2.9
6)
D) 2.3
E) 4.6
7) How many grams of oxygen are in 45 g of C2H2O2?
A) 17
B) 25
C) 31
7)
D) 9.3
1
E) 8.3
8)
8) Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:
CaO (s) + H2O (l) → Ca(OH)2 (s)
In a particular experiment, a 1.50-g sample of CaO is reacted with excess water and 1.48 g of
Ca(OH)2 is recovered. What is the percent yield in this experiment?
A) 99
B) 101.2
C) 74.8
D) 0.99
E) 2.16
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
9) Complete and balance the following reaction, given that elemental rubidium reacts
with elemental sulfur to form Rb2S (s).
9)
Na (s) + S (s) → __________
10)
10) Under appropriate conditions, nitrogen and hydrogen undergo a combination
reaction to yield ammonia:
N2 (g) + 3H2 (g) → 2NH3 (g)
A 9.3-g sample of hydrogen requires __________ g of N2 for a complete reaction.
11) The combustion of carbon disulfide in the presence of excess oxygen yields carbon
dioxide and sulfur dioxide:
11)
CS2 (g) + 3O2 (g) → CO2 (g) + 2SO2 (g)
The combustion of 15 g of CS2 in the presence of excess oxygen yields __________ g of
SO2.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
12)
12) Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:
CaO (s) + H2O (l) → Ca(OH)2 (s)
In a particular experiment, a 2.50-g sample of CaO is reacted with excess water and 2.80 g of
Ca(OH)2 is recovered. What is the percent yield in this experiment?
A) 112
B) 1.12
C) 84.9
D) 89.2
E) 3.60
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
13) If 2352 grams of FeS2 is allowed to react with 1408 grams of O2 according to the
following equation, how many grams of Fe 2O3 are produced?
FeS2 + O2 → Fe2O3 + SO2
2
13)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
14)
14) Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide:
CaO (s) + H2O (l) → Ca(OH)2 (s)
A 4.00-g sample of CaO is reacted with 3.86 g of H2O. How many grams of water remains
after completion of reaction?
A) 0.00793
B) 2.57
C) 1.04
D) 0.143
E) 0.00
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
15) Water can be formed from the stoichiometric reaction of hydrogen with oxygen:
15)
2H2 (g) + O2 (g) → 2H2O (g)
A complete reaction of 5.0 g of O2 with excess hydrogen produces __________ g of
H2O.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
16) A compound that is composed of only carbon and hydrogen contains 85.7% C and 14.3% H by
mass. What is the empirical formula of the compound?
A) CH2
B) C86H14
C) C4H8
D) C2H4
E) CH4
16)
17) Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide:
17)
PbCO3 (s) → PbO (s) + CO2 (g)
How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II)
carbonate?
A) 2.61
B) 2.50
C) 2.09
D) 0.41
E) 0.00936
18) Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to
yield ammonia:
18)
N2 (g) + 3H2 (g) → 2NH3 (g)
If the reaction yield is 87.5%, how many moles of N 2 are needed to produce 3.00 mol of NH3?.
A) 1.71
B) 0.166
C) 2.32
D) 1.00
E) 1.5
19) Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide:
PbCO3 (s) → PbO (s) + CO2 (g)
If the reaction yield is 95.7%, how many grams of lead (II) oxide will be produced by the
decomposition of 2.50 g of lead (II) carbonate?
A) 2.09
B) 1.04
C) 5.55
D) 1.55
E) 4.00
3
19)
20)
20) The combustion of ammonia in the presence of oxygen yields NO 2 and H2O:
4 NH3 (g) + 7 O2 (g) → 4 NO2 (g) + 6 H2O (g)
The combustion of 43.9 g of ammonia with 258 g of oxygen produces __________ g of NO 2.
A) 0.954
B) 212
C) 43.9
D) 178
4
E) 119
Answer Key
Testname: CHAPTER 3 EXERCISES
1) B
2) D
3) B
4) B
5) C
6) C
7) B
8) C
9) → Na2S (s)
10)
11)
12)
13)
14)
15)
16)
17)
18)
19)
20)
43
25
C
1280
B
5.6
A
C
A
A
E
5