Chemistry: The Central Science, 12e (Brown et al.)
Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations
3.1 Multiple-Choice Questions
1) When the following equation is balanced, the coefficients are __________.
C8H18 + O2 → CO2 + H2O
A) 2, 3, 4, 4
B) 1, 4, 8, 9
C) 2, 12, 8, 9
D) 4, 4, 32, 36
E) 2, 25, 16, 18
Answer: E
Diff: 2 Page Ref: Sec. 3.1
2) Of the reactions below, which one is not a combination reaction?
A) C + O2 → CO2
B) 2Mg + O2 → 2MgO
C) 2N2 + 3H2 → 2NH3
D) CaO + H2O → Ca(OH)2
E) 2CH4 + 4O2 → 2CO2 + 4H2O
Answer: E
Diff: 2 Page Ref: Sec. 3.2
3) When a hydrocarbon burns in air, what component of air reacts?
A) oxygen
B) nitrogen
C) carbon dioxide
D) water
E) argon
Answer: A
Diff: 2 Page Ref: Sec. 3.2
4) When a hydrocarbon burns in air, a component produced is?
A) oxygen
B) nitrogen
C) carbon
D) water
E) argon
Answer: D
Diff: 2 Page Ref: Sec. 3.2
5) Of the reactions below, which one is a decomposition reaction?
A) NH4Cl → NH3 + HCl
B) 2Mg + O2 → 2MgO
C) 2N2 + 3 H2 → 2NH3
D) 2CH4 + 4O2 → 2CO2 + 4H2O
E) Cd(NO3)O2 + Na2S → CdS + 2NaNO3
Answer: A
Diff: 3 Page Ref: Sec. 3.2
6) Which one of the following substances is the product of this combination reaction?
Al (s) + I2 (s) → __________
A) AlI2
B) AlI
C) AlI3
D) Al2I3
E) Al3I2
Answer: C
Diff: 2 Page Ref: Sec. 3.2
7) Which one of the following is not true concerning automotive air bags?
A) They are inflated as a result of a decomposition reaction
B) They are loaded with sodium azide initially
C) The gas used for inflating them is oxygen
D) The two products of the decomposition reaction are sodium and nitrogen
E) A gas is produced when the air bag activates.
Answer: C
Diff: 2 Page Ref: Sec. 3.2
8) The reaction used to inflate automobile airbags __________.
A) produces sodium gas
B) is a combustion reaction
C) is a combination reaction
D) violates the law of conservation of mass
E) is a decomposition reaction
Answer: E
Diff: 2 Page Ref: Sec. 3.2
9) Which of the following are combination reactions?
1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l)
2) CaO (s) + CO2 (g) → CaCO3 (s)
3) Mg (s) + O2 (g) → MgO (s)
4) PbCO3 (s) → PbO (s) + CO2 (g)
A) 1, 2, and 3
B) 2 and 3
C) 1, 2, 3, and 4
D) 4 only
E) 2, 3, and 4
Answer: B
Diff: 3 Page Ref: Sec. 3.2
10) Which of the following are combustion reactions?
1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l)
2) CaO (s) + CO2 (g) → CaCO3 (s)
3) PbCO3 (s) → PbO (s) + CO2 (g)
4) CH3OH (l) + O2 (g) → CO2 (g) + H2O (l)
A) 1 and 4
B) 1, 2, 3, and 4
C) 1, 3, and 4
D) 2, 3, and 4
E) 3 and 4
Answer: A
Diff: 2 Page Ref: Sec. 3.2
11) Which of the following are decomposition reactions?
1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l)
2) CaO (s) + CO2 (g) → CaCO3 (s)
3) Mg (s) + O2 (g) → MgO (s)
4) PbCO3 (s) → PbO (s) + CO2 (g)
A) 1, 2, and 3
B) 4 only
C) 1, 2, 3, and 4
D) 2 and 3
E) 2, 3, and 4
Answer: B
Diff: 3 Page Ref: Sec. 3.2
12) The formula of nitrobenzene is C6H5N O2. The molecular weight of this compound is __________ amu.
A) 107.11
B) 43.03
C) 109.10
D) 123.11
E) 3.06
Answer: D
Diff: 2 Page Ref: Sec. 3.3
13) The formula weight of potassium dichromate (K2Cr2O7) is __________ amu.
A) 107.09
B) 255.08
C) 242.18
D) 294.18
E) 333.08
Answer: D
Diff: 2 Page Ref: Sec. 3.3
14) The formula weight of lead (II) carbonate (PbCO3) is __________ amu.
A) 207.2
B) 219.2
C) 235.2
D) 267.2
E) 273.2
Answer: D
Diff: 2 Page Ref: Sec. 3.3
15) The formula weight of potassium phosphate (K3PO4) is __________ amu.
A) 173.17
B) 251.37
C) 212.27
D) 196.27
E) 86.07
Answer: C
Diff: 2 Page Ref: Sec. 3.3
16) The formula weight of aluminum sulfate (Al2(SO4)3) is __________ amu.
A) 342.15
B) 123.04
C) 59.04
D) 150.14
E) 273.06
Answer: A
Diff: 2 Page Ref: Sec. 3.3
17) The formula weight of silver chromate (Ag2CrO4) is __________ amu.
A) 159.87
B) 223.87
C) 331.73
D) 339.86
E) 175.87
Answer: C
Diff: 2 Page Ref: Sec. 3.3
18) The formula weight of ammonium sulfate ((NH4)O2SO4), rounded to the nearest integer, is __________ amu.
A) 100
B) 118
C) 116
D) 132
E) 264
Answer: D
Diff: 2 Page Ref: Sec. 3.3
19) The molecular weight of the acetic acid (CH3CO2H), rounded to the nearest integer, is __________ amu.
A) 60
B) 48
C) 44
D) 32
Answer: A
Diff: 1 Page Ref: Sec. 3.3
20) The molecular weight of the ethanol (C2H5OH), rounded to the nearest integer, is __________ amu.
A) 34
B) 41
C) 30
D) 46
E) 92
Answer: D
Diff: 1 Page Ref: Sec. 3.3
21) The molecular weight of glucose (C6H12O6), rounded to the nearest integer, is __________ amu.
A) 24
B) 96
C) 136
D) 180
E) 224
Answer: D
Diff: 1 Page Ref: Sec. 3.3
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22) What is the mass % of carbon in dimethylsulfoxide (C2H6SO) rounded to three significant figures?
A) 60.0
B) 20.6
C) 30.7
D) 7.74
E) 79.8
Answer: C
Diff: 3 Page Ref: Sec. 3.3
23) The mass % of H in methane (CH4) is __________.
A) 25.13
B) 4.032
C) 74.87
D) 92.26
E) 7.743
Answer: A
Diff: 2 Page Ref: Sec. 3.3
24) The mass % of Al in aluminum sulfate (Al2(SO4)3) is __________.
A) 7.886
B) 15.77
C) 21.93
D) 45.70
E) 35.94
Answer: B
Diff: 3 Page Ref: Sec. 3.3
25) The formula weight of a substance is __________.
A) identical to the molar mass
B) the same as the percent by mass weight
C) determined by combustion analysis
D) the sum of the atomic weights of each atom in its chemical formula
E) the weight of a sample of the substance
Answer: D
Diff: 1 Page Ref: Sec. 3.3
26) The formula weight of calcium nitrate (Ca(NO3)2), rounded to one decimal place, is __________
amu.
A) 102.1
B) 164.0
C) 204.2
D) 150.1
E) 116.1
Answer: B
Diff: 2 Page Ref: Sec. 3.3
27) The formula weight of magnesium fluoride (MgF2), rounded to one decimal place, is __________
amu.
A) 86.6
B) 43.3
C) 62.3
D) 67.6
E) 92.9
Answer: C
Diff: 2 Page Ref: Sec. 3.3
28) The formula weight of lead nitrate (Pb(NO3)2) is __________ amu.
A) 269.2
B) 285.2
C) 317.2
D) 331.2
E) 538.4
Answer: D
Diff: 2 Page Ref: Sec. 3.3
29) The mass % of C in methane (CH4) is __________.
A) 25.13
B) 133.6
C) 74.87
D) 92.26
E) 7.743
Answer: C
Diff: 2 Page Ref: Sec. 3.4
30) The mass % of F in the binary compound KrF2 is __________.
A) 18.48
B) 45.38
C) 68.80
D) 81.52
E) 31.20
Answer: E
Diff: 2 Page Ref: Sec. 3.4
31) Calculate the percentage by mass of nitrogen in PtCl2(NH3)2.
A) 4.67
B) 9.34
C) 9.90
D) 4.95
E) 12.67
Answer: B
Diff: 2 Page Ref: Sec. 3.4
32) Calculate the percentage by mass of lead in Pb(NO3)2.
A) 38.6
B) 44.5
C) 62.6
D) 65.3
E) 71.2
Answer: C
Diff: 2 Page Ref: Sec. 3.4
33) Calculate the percentage by mass of nitrogen in Pb(NO3)2.
A) 4.2
B) 5.2
C) 8.5
D) 10.4
E) 12.6
Answer: C
Diff: 2 Page Ref: Sec. 3.4
34) Calculate the percentage by mass of lead in PbCO3.
A) 17.96
B) 22.46
C) 73.05
D) 77.54
E) 89.22
Answer: D
Diff: 2 Page Ref: Sec. 3.4
35) Calculate the percentage by mass of oxygen in Pb(NO3)2
A) 9.7
B) 14.5
C) 19.3
D) 29.0
E) 33.4
Answer: D
Diff: 2 Page Ref: Sec 3.4
36) Calculate the percentage by mass of chlorine in PtCl2(NH3)2.
A) 23.63
B) 11.82
C) 25.05
D) 12.53
E) 18.09
Answer: A
Diff: 3 Page Ref: Sec. 3.4
37) Calculate the percentage by mass of hydrogen in PtCl2(N H3)2
A) 1.558
B) 1.008
C) 0.672
D) 0.034
E) 2.016
Answer: E
Diff: 3 Page Ref: Sec. 3.4
38) One mole of __________ contains the largest number of atoms.
A) S8
B) C10H8
C) Al2(SO4)3
D) Na3PO4
E) Cl2
Answer: B
Diff: 2 Page Ref: Sec. 3.4
39) One mole of __________ contains the smallest number of atoms.
A) S8
B) C10H8
C) Al2(SO4)3
D) Na3PO4
E) NaCl
Answer: E
Diff: 1 Page Ref: Sec. 3.4
40) One million argon atoms is __________ mol (rounded to two significant figures) of argon atoms.
A) 3.0
B) 1.7 × 10-18
C) 6.0 × 1023
D) 1.0 × 10-6
E) 1.0 × 10+6
Answer: B
Diff: 2 Page Ref: Sec. 3.4
41) There are __________ atoms of oxygen are in 300 molecules of CH3CO2H.
A) 300
B) 600
C) 3.01 × 1024
D) 3.61 × 1026
E) 1.80 × 1026
Answer: B
Diff: 2 Page Ref: Sec. 3.4
42) How many molecules of CH4 are in 48.2 g of this compound?
A) 5.00 × 1024
B) 3.00
C) 2.90 × 1025
D) 1.81 × 1024
E) 4.00
Answer: D
Diff: 3 Page Ref: Sec. 3.4
43) A 30.5 gram sample of glucose (C6H12O6) contains __________ mol of glucose.
A) 0.424
B) 0.169
C) 5.90
D) 2.36
E) 0.136
Answer: B
Diff: 2 Page Ref: Sec. 3.4
44) A 30.5 gram sample of glucose (C6H12O6) contains __________ atoms of carbon.
A) 1.02 x 1023
B) 6.12 x 1023
C) 6.02 x 1023
D) 2.04 x 1023
E) 1.22 x 1024
Answer: B
Diff: 3 Page Ref: Sec 3.4
45) A sample of CH2F2 with a mass of 19 g contains __________ atoms of F.
A) 2.2 × 1023
B) 38
C) 3.3 × 1024
D) 4.4 × 1023
E) 9.5
Answer: D
Diff: 3 Page Ref: Sec. 3.4
46) A sample of CH4O with a mass of 32.0 g contains __________ molecules of CH4O.
A) 5.32 × 10-23
B) 1.00
C) 1.88 × 1022
D) 6.02 × 1023
E) 32.0
Answer: D
Diff: 2 Page Ref: Sec. 3.4
47) How many atoms of nitrogen are in 10 g of NH4NO3?
A) 3.5
B) 1.5 × 1023
C) 3.0 × 1023
D) 1.8
E) 2
Answer: B
Diff: 3 Page Ref: Sec. 3.4
48) Gaseous argon has a density of 1.40 g/L at standard conditions. How many argon atoms are in 1.00
L of argon gas at standard conditions?
A) 4.76 × 1022
B) 3.43 × 1026
C) 2.11 × 1022
D) 1.59 × 1025
E) 6.02 × 1023
Answer: C
Diff: 4 Page Ref: Sec. 3.4
49) What is the mass in grams of 9.76 × 1012 atoms of naturally occurring sodium?
A) 22.99
B) 1.62 × 10-11
C) 3.73 × 10-10
D) 7.05 × 10-13
E) 2.24 × 1014
Answer: C
Diff: 3 Page Ref: Sec. 3.4
50) How many moles of pyridine (C5H5N) are contained in 3.13 g of pyridine?
A) 0.0396
B) 25.3
C) 0.319
D) 0.00404
E) 4.04 × 103
Answer: A
Diff: 3 Page Ref: Sec. 3.4
51) How many oxygen atoms are contained in 2.74 g of Al2(SO4)3?
A) 12
B) 6.02 × 1023
C) 7.22 × 1024
D) 5.79 × 1022
E) 8.01 × 10-3
Answer: D
Diff: 3 Page Ref: Sec. 3.4
52) The total number of atoms in 0.111 mol of Fe(CO)3(PH3)2 is
A) 15.0
B) 1.00 × 1024
C) 4.46 × 1021
D) 1.67
E) 2.76 × 10-24
Answer: B
Diff: 3 Page Ref: Sec. 3.4
53) How many sulfur dioxide molecules are there in 1.80 mol of sulfur dioxide?
A) 1.08 × 1023
B) 6.02 × 1024
C) 1.80 × 1024
D) 1.08 × 1024
E) 6.02 × 1023
Answer: D
Diff: 2 Page Ref: Sec. 3.4
54) How many sulfur dioxide molecules are there in 0.180 mol of sulfur dioxide?
A) 1.80 × 1023
B) 6.02 × 1024
C) 6.02 × 1023
D) 1.08 × 1024
E) 1.08 × 1023
Answer: E
Diff: 2 Page Ref: Sec. 3.4
55) How many carbon atoms are there in 52.06 g of carbon dioxide?
A) 5.206 × 1024
B) 3.134 × 1025
C) 7.122 × 1023
D) 8.648 × 10-23
E) 1.424 × 1024
Answer: C
Diff: 3 Page Ref: Sec. 3.4
56) How many oxygen atoms are there in 52.06 g of carbon dioxide?
A) 1.424 × 1024
B) 6.022 × 1023
C) 1.204 × 1024
D) 5.088 × 1023
E) 1.018 × 1024
Answer: A
Diff: 3 Page Ref: Sec. 3.4
57) How many moles of sodium carbonate contain 1.773 × 1017 carbon atoms?
A) 5.890 × 10-7
B) 2.945 × 10-7
C) 1.473 × 10-7
D) 8.836 × 10-7
E) 9.817 × 10-8
Answer: B
Diff: 2 Page Ref: Sec. 3.4
58) How many grams of sodium carbonate contain 1.773 × 1017 carbon atoms?
A) 3.121 × 10-5
B) 1.011 × 10-5
C) 1.517 × 10-5
D) 9.100 × 10-5
E) 6.066 × 10-5
Answer: A
Diff: 2 Page Ref: Sec. 3.4
59) The compound responsible for the characteristic smell of garlic is allicin, C6H10OS2. The mass of 1.00 mol of allicin, rounded to the nearest integer, is __________ g.
A) 34
B) 162
C) 86
D) 61
E) 19
Answer: B
Diff: 1 Page Ref: Sec. 3.4
60) The molecular formula of aspartame, the generic name of NutraSweet®, is C14H18N2O5. The molar mass of aspartame, rounded to the nearest integer, is __________ g.
A) 24
B) 156
C) 294
D) 43
E) 39
Answer: C
Diff: 1 Page Ref: Sec. 3.4
61) There are ________ oxygen atoms in 30 molecules of C20H42S3O2.
A) 6.0 x 1023
B) 1.8 x 1025
C) 3.6 x 1025
D) 1.2 x 1024
E) 60
Answer: E
Diff: 2 Page Ref: Sec. 3.4
62) A nitrogen oxide is 63.65% by mass nitrogen. The molecular formula could be __________.
A) NO
B) NO2
C) N2O
D) N2O4
E) either NO2 or N2O4
Answer: C
Diff: 3 Page Ref: Sec. 3.5
63) A sulfur oxide is 50.0% by mass sulfur. This molecular formula could be __________.
A) SO
B) SO2
C) S2O
D) S2O4
E) either SO2 or S2O4
Answer: E
Diff: 3 Page Ref: Sec. 3.5
64) Which hydrocarbon pair below have identical mass percentage of C?
A) C3H4 and C3H6
B) C2H4 and C3H4
C) C2H4 and C4H2
D) C2H4 and C3H6
E) none of the above
Answer: D
Diff: 3 Page Ref: Sec. 3.5
65) Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are produced by the reaction of 5.0 grams of O2 with 6.0 grams of S. What is the % yield of SO3 in this experiment?
S (s) + O2 (g) → SO3 (g) (not balanced)
A) 32
B) 63
C) 75
D) 95
E) 99
Answer: D
Diff: 4 Page Ref: Sec. 3.7
66) Propane (C3H8) reacts with oxygen in the air to produce carbon dioxide and water. In a particular experiment, 38.0 grams of carbon dioxide are produced from the reaction of 22.05 grams of propane with excess oxygen. What is the % yield in this reaction?
A) 38.0
B) 57.6
C) 66.0
D) 86.4
E) 94.5
Answer: B
Diff: 5 Page Ref: Sec 3.7
3.2 Bimodal Questions
1) When the following equation is balanced, the coefficients are __________.
NH3 (g) + O2 (g) → NO2 (g) + H2O (g)
A) 1, 1, 1, 1
B) 4, 7, 4, 6
C) 2, 3, 2, 3
D) 1, 3, 1, 2
E) 4, 3, 4, 3
Answer: B
Diff: 1 Page Ref: Sec. 3.1
2) When the following equation is balanced, the coefficients are __________.
Al(NO3)3 + Na2S → Al2S3 + NaNO3
A) 2, 3, 1, 6
B) 2, 1, 3, 2
C) 1, 1, 1, 1
D) 4, 6, 3, 2
E) 2, 3, 2, 3
Answer: A
Diff: 1 Page Ref: Sec. 3.1
3) When the following equation is balanced, the coefficient of H2 is __________.
K (s) + H2O (l) → KOH (aq) + H2 (g)
A) 1
B) 2
C) 3
D) 4
E) 5
Answer: A
Diff: 1 Page Ref: Sec. 3.1
4) When the following equation is balanced, the coefficient of Al is __________.
Al (s) + H2O (l) → Al(OH)3 (s) + H2 (g)
A) 1
B) 2
C) 3
D) 5
E) 4
Answer: B
Diff: 1 Page Ref: Sec. 3.1
5) When the following equation is balanced, the coefficient of H2O is __________.
Ca (s) + H2O (l) → Ca(OH)2 (aq) + H2 (g)
A) 1
B) 2
C) 3
D) 5
E) 4
Answer: B
Diff: 1 Page Ref: Sec. 3.1
6) When the following equation is balanced, the coefficient of Al2O3 is __________.
Al2O3 (s) + C (s) + Cl2 (g) → AlCl3 (s) + CO (g)
A) 1 B) 2 C) 3 D) 4 E) 5
Answer: A
Diff: 1 Page Ref: Sec. 3.1
7) When the following equation is balanced, the coefficient of H2S is __________.
FeCl3 (aq) + H2S (g) → Fe2S3 (s) + HCl (aq)
A) 1 B) 2
C) 3
D) 5
E) 4
Answer: C
Diff: 1 Page Ref: Sec. 3.1
8) When the following equation is balanced, the coefficient of HCl is __________.
CaCO3 (s) + HCl (aq) → CaCl2 (aq) + CO2 (g) + H2O (l)
A) 1
B) 2
C) 3 D) 4 E) 0
Answer: B
Diff: 1 Page Ref: Sec. 3.1
9) When the following equation is balanced, the coefficient of HNO3 is __________.
HNO3 (aq) + CaCO3 (s) → Ca(NO3)2 (aq) + CO2 (g) + H2O (l)
A) 1 B) 2
C) 3 D) 5 E) 4
Answer: B
Diff: 1 Page Ref: Sec. 3.1
10) When the following equation is balanced, the coefficient of H3PO4 is __________.
H3PO4 (aq) + NaOH (aq) → Na3PO4 (aq) + H2O (l)
A) 1
B) 2
C) 3
D) 4
E) 0
Answer: A
Diff: 1 Page Ref: Sec. 3.1
11) When the following equation is balanced, the coefficient of C3H8O3 is __________.
C3H8O3 (g) + O2 (g) → CO2 (g) + H2O (g)
A) 1
B) 2
C) 3
D) 7
E) 5
Answer: B
Diff: 1 Page Ref: Sec. 3.1
12) When the following equation is balanced, the coefficient of O2 is __________.
C2H4O (g) + O2 (g) → CO2 (g) + H2O (g)
A) 2
B) 3
C) 4
D) 5
E) 1
Answer: D
Diff: 1 Page Ref: Sec. 3.1
13) When the following equation is balanced, the coefficient of H2 is __________.
CO (g) + H2 (g) → H2O (g) + CH4 (g)
A) 1
B) 2
C) 3
D) 4
E) 0
Answer: C
Diff: 1 Page Ref: Sec. 3.1
14) When the following equation is balanced, the coefficient of H2SO4 is __________.
H2SO4 (aq) + NaOH (aq) → Na2SO4 (aq) + H2O (l)
A) 1
B) 2
C) 3
D) 4
E) 0.5
Answer: A
Diff: 1 Page Ref: Sec. 3.1
15) When the following equation is balanced, the coefficient of water is __________.
K (s) + H2O (l) → KOH (aq) + H2 (g)
A) 1
B) 2
C) 3
D) 4
E) 5
Answer: B
Diff: 1 Page Ref: Sec. 3.1
16) When the following equation is balanced, the coefficient of hydrogen is __________.
K (s) + H2O (l) → KOH (aq) + H2 (g)
A) 1
B) 2
C) 3
D) 4
E) 5
Answer: A
Diff: 1 Page Ref: Sec. 3.1
17) When the following equation is balanced, the coefficient of oxygen is __________.
PbS (s) + O2 (g) → PbO (s) + SO2 (g)
A) 1
B) 3
C) 2
D) 4
E) 5
Answer: B
Diff: 1 Page Ref: Sec. 3.1
18) When the following equation is balanced, the coefficient of sulfur dioxide is __________.
PbS (s) + O2 (g) → PbO (s) + SO2 (g)
A) 5 B) 1
C) 3
D) 2
E) 4
Answer: D
Diff: 1 Page Ref: Sec. 3.1
19) When the following equation is balanced, the coefficient of dinitrogen pentoxide is __________.
N2O5 (g) + H2O (l) → HNO3 (aq)
A) 1 B) 2
C) 3
D) 4
E) 5
Answer: A
Diff: 1 Page Ref: Sec. 3.1
20) When the following equation is balanced, the coefficient of water is __________.
N2O5 (g) + H2O (l) → HNO3 (aq)
A) 5 B) 2
C) 3 D) 4
E) 1
Answer: E
Diff: 1 Page Ref: Sec. 3.1
21) When the following equation is balanced, the coefficient of nitric acid is __________.
N2O5 (g) + H2O (l) → HNO3 (aq)
A) 5 B) 2
C) 3
D) 4
E) 1
Answer: B
Diff: 1 Page Ref: Sec. 3.1
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