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
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
3) When a hydrocarbon burns in air, what component of air reacts?
A) oxygen
B) nitrogen
C) carbon dioxide
D) water
E) argon
4) When a hydrocarbon burns in air, a component produced is?
A) oxygen
B) nitrogen
C) carbon
D) water
E) argon
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
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
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.
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
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
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
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
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
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
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
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
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
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
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
19) The molecular weight of the acetic acid (CH3CO2H), rounded to the nearest integer, is __________
amu.
A) 60
B) 48
C) 44
D) 32
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
21) The molecular weight of glucose (C6H12O6), rounded to the nearest integer, is __________ amu.
A) 24
B) 96
C) 136
D) 180
E) 224
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
23) The mass % of H in methane (CH4) is __________.
A) 25.13
B) 4.032
C) 74.87
D) 92.26
E) 7.743
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
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
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
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
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
29) The mass % of C in methane (CH4) is __________.
A) 25.13
B) 133.6
C) 74.87
D) 92.26
E) 7.743
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
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
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
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
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
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
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
9
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
38) One mole of __________ contains the largest number of atoms.
A) S8
B) C10H8
C) Al2(SO4)3
D) Na3PO4
E) Cl2
39) One mole of __________ contains the smallest number of atoms.
A) S8
B) C10H8
C) Al2(SO4)3
D) Na3PO4
E) NaCl
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
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
42) How many molecules of CH4 are in 48.2 g of this compound?
10
A) 5.00 × 1024
B) 3.00
C) 2.90 × 1025
D) 1.81 × 1024
E) 4.00
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
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
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
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
47) How many atoms of nitrogen are in 10 g of NH4NO3?
A) 3.5
11
B) 1.5 × 1023
C) 3.0 × 1023
D) 1.8
E) 2
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
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
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
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
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
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
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
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
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
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
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
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
14
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
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
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
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
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
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
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
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
16
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
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
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
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
6) When the following equation is balanced, the coefficient of Al2O3 is __________.
17
Al2O3 (s) + C (s) + Cl2 (g) → AlCl3 (s) + CO (g)
A) 1
B) 2
C) 3
D) 4
E) 5
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
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
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
10) When the following equation is balanced, the coefficient of H3PO4 is __________.
18
H3PO4 (aq) + NaOH (aq) → Na3PO4 (aq) + H2O (l)
A) 1
B) 2
C) 3
D) 4
E) 0
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
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
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
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
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
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
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
20
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
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
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
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
22) Write the balanced equation for the reaction that occurs when methanol, CH3OH (l), is burned in air.