21) The volume of 0.25 mol of a gas at 72.7 kPa and 15 °C is ________ m3.
A) 8.1 × 10-5
B) 1.2 × 10-4
C) 4.3 × 10–4
D) 8.2 × 10-3
E) 2.2 × 10-1
22) A gas in a 325 mL container has a pressure of 695 torr at 19 °C. There are ________ mol of gas in the
flask.
A) 1.24 × 10-2
B) 1.48 × 10-2
C) 9.42
D) 12.4
E) 80.6
23) A 0.133 mol sample of gas in a 525 mL container has a pressure of 312 torr. The temperature of the gas
is ________ °C.
A) 20.3
B) -253
C) -20.3
D) 203
E) 22.4
24) The mass of nitrogen dioxide contained in a 4.32 L vessel at 48 °C and 141600 Pa is ________ g.
A) 5.35 × 104
B) 53.5
C) 10.5
D) 70.5
E) 9.46 × 10-2
25) The density of ammonia gas in a 4.32 L container at 837 torr and 45.0 °C is ________ g/L.
A) 3.86
B) 0.719
C) 0.432
D) 0.194
E) 4.22 × 10-2
26) The density of N2O at 1.53 atm and 45.2 °C is ________ g/L.
A) 18.2
B) 1.76
C) 0.388
D) 9.99
E) 2.58
27) The molecular weight of a gas is ________ g/mol if 3.5 g of the gas occupies 2.1 L at STP.
A) 41
B) 5.5 × 103
C) 37
D) 4.6 × 102
E) 2.7 × 10-2
28) The molecular weight of a gas is ________ g/mol if 6.7 g of the gas occupies 6.3 L at STP.
A) 24
B) 3.6 × 103
C) 27
D) 3.0 × 102
E) 1.8 × 10-2
29) The molecular weight of a gas that has a density of 6.70 g/L at STP is ________ g/mol.
A) 4.96 × 102
B) 1.50 × 102
C) 7.30 × 101
D) 3.35
E) 2.98 × 10-1
30) The molecular weight of a gas that has a density of 7.10 g/L at 25.0 °C and 1.00 atm pressure is
________ g/mol.
A) 174
B) 14.6
C) 28.0
D) 5.75 × 10-3
E) 6.85 × 10-2
31) The molecular weight of a gas that has a density of 5.75 g/L at STP is ________ g/mol.
A) 3.90
B) 129
C) 141
D) 578
E) 1.73 × 10-3
32) The density of chlorine (Cl2) gas at 25 °C and 60. kPa is ________ g/L.
A) 20
B) 4.9
C) 1.7
D) 0.86
E) 0.58
24
33) The volume of hydrogen gas at 38.0 °C and 763 torr that can be produced by the reaction of 4.33 g of
zinc with excess sulfuric acid is ________ L.
A) 1.68
B) 2.71 × 10-4
C) 3.69 × 104
D) 2.84
E) 0.592
34) The volume of hydrogen gas at 45.0 °C and 699 torr that can be produced by the reaction of 5.66 g of
zinc with excess sulfuric acid is ________ L.
A) 2.84
B) 2.71 × 10-4
C) 3.69 × 104
D) 2.45
E) 0.592
35) The volume of HCl gas required to react with excess magnesium metal to produce 6.82 L of hydrogen
gas at 2.19 atm and 35.0 °C is ________ L.
A) 6.82
B) 2.19
C) 13.6
D) 4.38
E) 3.41
36) The volume of fluorine gas required to react with 2.67 g of calcium bromide to form calcium fluoride
and bromine at 41.0 °C and 4.31 atm is ________ mL.
A) 10.4
B) 210
C) 420
D) 79.9
E) 104
37) The volume of fluorine gas required to react with 4.26 g of calcium bromide to form calcium fluoride
and bromine at 25.0 °C and 4195 torr is ________ L.
A) 0.0943
B) 0.241
C) 241
D) 1.24 × 10-4
E) 0.124
38) What volume (mL) of sulfur dioxide can be produced by the complete reaction of 3.82 g of calcium
sulfite with excess HCl (aq), when the final SO2 pressure is 827 torr at 44.0 °C?
A) 7.60 × 102
B) 1.39 × 10-4
C) 1.00 × 10-3
D) 0.106
E) 5.78 × 102
39) Automobile air bags use the decomposition of sodium azide as their source of gas for rapid inflation:
2NaN3 (s) → 2Na (s) + 3N2 (g).
What mass (g) of NaN3 is required to provide 40.0 L of N2 at 25.0 °C and 763 torr?
A) 1.64
B) 1.09
C) 160
D) 71.1
E) 107
40) Automobile air bags use the decomposition of sodium azide as their source of gas for rapid inflation:
2NaN3 (s) → 2Na (s) + 3N2 (g).
What mass (g) of NaN3 is required to provide 26.5 L of N2 at 22.0 °C and 1.10 atm?
A) 52.2
B) 700.
C) 0.807
D) 1.21
E) 1.10
41) The Mond process produces pure nickel metal via the thermal decomposition of nickel tetracarbonyl:
Ni(CO)4 (l) → Ni (s) + 4CO (g).
What volume (L) of CO is formed from the complete decomposition of 444 g of Ni(CO)4 at 752 torr and
22.0 °C?
A) 0.356
B) 63.7
C) 255
D) 20.2
E) 11.0
42) What volume (L) of NH3 gas at STP is produced by the complete reaction of 7.5 g of H2O according to
the following reaction?
Mg3N2 (s) + 6H2O (l) → 3Mg(OH)2 (aq) + 2NH3 (g)
A) 3.1
B) 9.3
C) 19
D) 28
E) 0.32
43) Ammonium nitrite undergoes thermal decomposition to produce only gases:
NH4NO2 (s) → N2 (g) + 2H2O (g)
What volume (L) of gas is produced by the decomposition of 35.0 g of NH4NO2(s) at 525 °C and 1.5 atm?
A) 48
B) 160
C) 15
D) 72
E) 24
44) The thermal decomposition of potassium chlorate can be used to produce oxygen in the laboratory.
2KClO3 (s) → 2KCl (s) + 3O2 (g)
What volume (L) of O2 gas at 25 °C and 1.00 atm pressure is produced by the decomposition of 7.5 g of
KClO3 (s)?
A) 4.5
B) 7.5
C) 2.3
D) 3.7
E) 11
45) Since air is a mixture, it does not have a “molar mass.” However, for calculation purposes, it is
possible to speak of its “effective molar mass.” (An effective molar mass is a weighted average of the
molar masses of a mixture’s components.) If air at STP has a density of 1.285 g/L, its effective molar mass
is ________ g/mol.
A) 26.94
B) 31.49
C) 30.00
D) 34.42
E) 28.80
46) A vessel contained N2, Ar, He, and Ne. The total pressure in the vessel was 987 torr. The partial
pressures of nitrogen, argon, and helium were 44.0, 486, and 218 torr, respectively. The partial pressure of
neon in the vessel was ________ torr.
A) 42.4
B) 521
C) 19.4
D) 239
E) 760
47) The pressure in a 12.2 L vessel that contains 2.34 g of carbon dioxide, 1.73 g of sulfur dioxide, and 3.33
g of argon, all at 42 °C is ________ mm Hg.
A) 263
B) 134
C) 395
D) 116
E) 0.347
48) A sample of He gas (3.0 L) at 5.6 atm and 25 °C was combined with 4.5 L of Ne gas at 3.6 atm and 25
°C at constant temperature in a 9.0 L flask. The total pressure in the flask was ________ atm. Assume the
initial pressure in the flask was 0.00 atm and the temperature upon mixing was 25 °C.
A) 2.6
B) 9.2
C) 1.0
D) 3.7
E) 24
49) A sample of H2 gas (2.0 L) at 3.5 atm was combined with 1.5 L of N2 gas at 2.6 atm pressure at a
constant temperature of 25 °C into a 7.0 L flask. The total pressure in the flask is ________ atm. Assume
the initial pressure in the flask was 0.00 atm and the temperature upon mixing was 25 °C.
A) 0.56
B) 2.8
C) 1.0
D) 1.6
E) 24
50) In a gas mixture of He, Ne, and Ar with a total pressure of 8.40 atm, the mole fraction of Ar is
________ if the partial pressures of He and Ne are 1.50 and 2.00 atm, respectively.
A) 0.179
B) 0.238
C) 0.357
D) 0.583
E) 0.417
51) A gas mixture of Ne and Ar has a total pressure of 4.00 atm and contains 16.0 mol of gas. If the partial
pressure of Ne is 2.75 atm, how many moles of Ar are in the mixture?
A) 11.0
B) 5.00
C) 6.75
D) 9.25
E) 12.0
52) A gas mixture of N2 and CO2 has a total pressure of 8.00 atm and contains 12.5 mol of gas. If the
partial pressure of N2 is 3.69 atm, how many moles of CO2 are in the mixture?
A) 5.77
B) 3.69
C) 4.31
D) 11.0
E) 6.73
53) A mixture of He and Ne at a total pressure of 0.95 atm is found to contain 0.32 mol of He and 0.56 mol
of Ne. The partial pressure of Ne is ________ atm.
A) 1.7
B) 1.5
C) 0.60
D) 0.35
E) 1.0
54) A flask contains a mixture of He and Ne at a total pressure of 2.6 atm. There are 2.0 mol of He and 5.0
mol of Ne in the flask. The partial pressure of He is ________ atm.
A) 9.1
B) 6.5
C) 1.04
D) 0.74
E) 1.86
55) Sodium hydride reacts with excess water to produce aqueous sodium hydroxide and hydrogen gas:
NaH (s) + H2O (l) → NaOH (aq) + H2 (g)
A sample of NaH weighing ________ g will produce 982 mL of gas at 28.0 °C and 765 torr, when the
hydrogen is collected over water. The vapor pressure of water at this temperature is 28 torr.
A) 2.93
B) 0.960
C) 0.925
D) 0.0388
E) 925
56) SO2 (5.00 g) and CO2 (5.00 g) were placed in a 750.0 mL container at 50.0 °C. The total pressure in the
container was ________ atm.
A) 0.192
B) 4.02
C) 2.76
D) 6.78
E) 1.60
57) SO2 (5.00 g) and CO2 (5.00 g) are placed in a 750.0 mL container at 50.0 °C. The partial pressure of
SO2 in the container was ________ atm.
A) 2.76
B) 4.02
C) 6.78
D) 0.192
E) 1.60
58) SO2 (5.00 g) and CO2 (5.00 g) were placed in a 750.0 mL container at 50.0 °C. The partial pressure of
CO2 in the container was ________ atm.
A) 6.78
B) 2.76
C) 1.60
D) 0.192
E) 4.02
59) CO (5.00 g) and CO2 (5.00 g) were placed in a 750.0 mL container at 50.0 °C. The total pressure in the
container was ________ atm.
A) 10.3
B) 4.02
C) 6.31
D) 0.292
E) 1.60
32
60) CO (5.00 g) and CO2 (5.00 g) were placed in a 750.0 mL container at 50.0 °C. The partial pressure of
CO in the container was ________ atm.
A) 6.29
B) 4.02
C) 10.3
D) 0.292
E) 1.60
61) CO (5.00 g) and CO2 (5.00 g) were placed in a 750.0 mL container at 50.0 °C. The partial pressure of
CO2 in the container was ________ atm.
A) 4.02
B) 10.3
C) 1.60
D) 0.292
E) 6.31
62) The root-mean-square speed of CO at 113 °C is ________ m/s.
A) 317
B) 58.3
C) 586
D) 993
E) 31.5
63) A sample of N2 gas (2.0 mmol) effused through a pinhole in 5.5 s. It will take ________ s for the same
amount of CH4 to effuse under the same conditions.
A) 7.3
B) 5.5
C) 3.1
D) 4.2
E) 9.6
64) A sample of O2 gas (2.0 mmol) effused through a pinhole in 5.0 s. It will take ________ s for the same
33
amount of CO2 to effuse under the same conditions.
A) 4.3
B) 0.23
C) 3.6
D) 5.9
E) 6.9
65) A sample of He gas (2.0 mmol) effused through a pinhole in 53 s. The same amount of an unknown
gas, under the same conditions, effused through the pinhole in 248 s. The molecular mass of the unknown
gas is ________ g/mol.
A) 0.19
B) 5.5
C) 88
D) 19
E) 350
66) Using the van der Waals equation, the pressure in a 22.4 L vessel containing 1.00 mol of neon gas at
is ________ atm. (a = 0.211 L2-atm/mol2, b = 0.0171 L/mol)
A) 0.730
B) 1.00
C) 1.21
D) 1.37
E) 0.367
67) Using the van der Waals equation, the pressure in a 22.4 L vessel containing 1.50 mol of chlorine gas
at 0.00 °C is ________ atm. (a = 6.49 L2-atm/mol2, b = 0.0562 L/mol)
A) 0.993
B) 1.50
C) 0.676
D) 1.91
E) 1.48
10.3 Algorithmic Questions
1) Molecular compounds of low molecular weight tend to be gases at room temperature. Which of the
following is most likely not a gas at room temperature?
A) KBr
B) F2
C) HCN
D) SO2
E) CH4
2) A pressure of 0.500 atm is the same as a pressure of ________ of mm Hg.
A) 193
B) 760.
C) 380.
D) 29.9
E) 33.0
3) A closed-end manometer was attached to a vessel containing argon. The difference in the mercury
levels in the two arms of the manometer was 9.60 cm. Atmospheric pressure was 783 mm Hg. The
pressure of the argon in the container was ________ mm Hg.
A) 96.0
B) 661
C) 773
D) 793
E) 882