20) The temperature of a sample of CH4 gas (10.34 g) in a 50.0 L vessel at 1.33 atm is __________ °C.
A) 984
B) -195
C) 195
D) 1260
E) -1260
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
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 x 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) 47
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) 2.0
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
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 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
100°C 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) A pressure of 1.25 atm is the same as a pressure of __________ of mm Hg.
A) 193
B) 760.
C) 950.
D) 29.9
E) 33.0
2) 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 11.8 cm. Atmospheric pressure was 783 mm Hg. The
pressure of the argon in the container was __________ mm Hg.
A) 118
B) 661
C) 771
D) 795
E) 882
3) A fixed amount of gas at 25.0°C occupies a volume of 10.0 L when the pressure is 667 torr. Use
Boyle’s law to calculate the pressure (torr) when the volume is reduced to 7.88 L at a constant
temperature of 25.0°C.
A) 846
B) 0.118
C) 5.26 × 104
D) 526
E) 1.11
4) A fixed amount of gas at 25.0°C occupies a volume of 10.0 L when the pressure is 629 torr. Use
Charles’s law to calculate the volume (L) the gas will occupy when the temperature is increased to
121°C while maintaining the pressure at 629 torr.
A) 10.9
B) 13.2
C) 2.07
D) 7.56
E) 48.4
5) A sample of gas (24.2 g) initially at 6.00 atm was compressed from 8.00 L to 2.00 L at constant
temperature. After the compression, the gas pressure was __________ atm.
A) 12.0
B) 16.0
C) 18.0
D) 20.0
E) 24.0
6) A balloon originally had a volume of 4.39 L at 44°C and a pressure of 729 torr. The balloon must be
cooled to __________°C to reduce its volume to 3.78 L (at constant pressure).
A) 38.0
B) 0.00
C) 72.9
D) 273
E) 546
7) If 3.21 mol of a gas occupies 56.2 L at 44°C and 793 torr, 5.21 mol of this gas occupies __________
L under these conditions.
A) 14.7
B) 61.7
C) 30.9
D) 91.2
E) 478
8) A gas originally at 27°C and 1.00 atm pressure in a 3.9 L flask is cooled at constant pressure until the
temperature is 11°C. The new volume of the gas is __________ L.
A) 0.27
B) 3.7
C) 3.9
D) 4.1
E) 0.24
9) A sample of He gas (2.35 mol) occupies 57.9 L at 300.0 K and 1.00 atm. The volume of this sample
is __________ L at 423 K and 1.00 atm.
A) 0.709
B) 41.1
C) 81.6
D) 1.41
E) 57.9
10) A sample of an ideal gas (3.00 L) in a closed container at 25.0°C and 76.0 torr is heated to 340°C.
The pressure of the gas at this temperature is __________ torr.
A) 912
B) 156
C) 76.5
D) 39.5
E) 0.0253
11) At a temperature of __________°C, 0.444 mol of CO gas occupies 11.8 L at 912 torr.
A) 379
B) 73.0
C) 14.0
D) 32.0
E) 116
12) The pressure exerted by 1.5 mol of gas in a 13 L flask at 22°C is __________ kPa.
A) 560
B) 280
C) 18
D) 2.4
E) 1.0
13) A 0.325 L flask filled with gas at 0.851 atm and 19°C contains __________ mol of gas.
A) .0116
B) .0148
C) 9.42
D) 12.4
E) 80.7
14) A sample of gas (1.9 mol) is in a flask at 21°C and 697 mm Hg. The flask is opened and more gas is
added to the flask. The new pressure is 782 mm Hg and the temperature is now 26°C. There are now
__________ mol of gas in the flask.
A) 1.6
B) 2.1
C) 2.9
D) 3.5
E) 0.28
15) A sample of gas (1.3 mol) occupies __________ L at 22°C and 4.5 atm.
A) .079
B) .52
C) 7.0
D) 13
E) .032
16) The volume of 0.65 mol of an ideal gas at 365 torr and 97°C is __________ L.
A) .054
B) 9.5
C) 11
D) 41
E) .024
17) The volume occupied by 0.50 mol of gas at 35°C and 2.0 atm pressure is __________ L.
A) 38
B) 6.3
C) .72
D) .053
E) .026
18) The density of nitric oxide (NO) gas at 1.21 atm and 46.2°C is __________ g/L.
A) 0.0462
B) 0.722
C) 1.39
D) 0.319
E) 9.6
19) The density of krypton gas at 1.21 atm and 50.0°C is __________ g/L.
A) 0.0456
B) 0.262
C) 0.295
D) 3.82
E) 7.65
20) The density of chlorine gas at 1.21 atm and 34.9°C is __________ g/L.
A) 0.0479
B) 0.295
C) 0.423
D) 1.70
E) 3.39
21) A 1.44-g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of 1.00 atm and
a temperature of 100.0°C. The unknown gas is __________.
A) argon
B) helium
C) krypton
D) neon
E) xenon
22) Calcium hydride (CaH2) reacts with water to form hydrogen gas:
CaH2 (s) + 2H2O (l) → Ca(OH)2 (aq) + 2H2 (g)
How many grams of CaH2 are needed to generate 48.0 L of H2 gas at a pressure of 0.888 atm and a
temperature of 32°C?
A) 50.7
B) 0.851
C) 143
D) 35.8
E) 71.7
23) Given the equation:
C2H6 (g) + O2 (g) → CO2 (g) + H2O (g) (not balanced)
Determine the number of liters of CO2 formed at STP. when 240.0 grams of C2H6 is burned in excess
oxygen gas.
36
24) Given the equation:
C2H6 (g) + O2 (g) → CO2 (g) + H2O (g) (not balanced)
Determine the number of liters of O2 consumed at STP when 270.0 grams of C2H6 is burned.
25) Zinc reacts with aqueous sulfuric acid to form hydrogen gas:
Zn (s) + H2SO4 (aq) → ZnSO4 (aq) + H2 (g)
In an experiment, 225 mL of wet H2 is collected over water at 27°C and a barometric pressure of 748
torr. How many grams of Zn have been consumed? The vapor pressure of water at 27°C is 26.74 torr.
A) 4.79 × 106
B) 0.567
C) 567
D) 431
E) 4.31 × 105
26) Zinc reacts with aqueous sulfuric acid to form hydrogen gas:
Zn (s) + H2SO4 (aq) → ZnSO4 (aq) + H2 (g)
In an experiment, 201 mL of wet H2 is collected over water at 27°C and a barometric pressure of 733
torr. The vapor pressure of water at 27°C is 26.74 torr. The partial pressure of hydrogen in this
experiment is __________ atm.
A) 0.929
B) 706
C) 0.964
D) 760
E) 1.00
10.4 Short Answer Questions
1) Abnormally high blood pressure is called __________.
2) The temperature and pressure specified by STP are __________ °C and __________ atm.
3) How many molecules are there in 4.00 L of oxygen gas at 500 °C and 50.0 torr?
4) The volume of HCl gas required to react with excess Ca to produce 11.4 L of hydrogen gas at 1.62
atm and 62.0°C is __________ L.
5) What is the density (in g/L) of oxygen gas at 77.0°C and 700.0 torr?
6) What is the partial pressure (in mm Hg) of neon in a 4.00 L vessel that contains 0.838 mol of
methane, 0.184 mol of ethane, and 0.755 mol of neon at a total pressure of 928 mm Hg?
7) The rms speed of methane molecules at 45.0°C is __________ m/sec.
8) The deviation from ideal behavior of a gas is most evident at __________ and/or low temperature.
9) The van der Waals equation corrects the ideal gas law for the finite volume and __________ of gas
molecules.
10.5 True/False Questions
1) The main component of air is oxygen.
2) If the temperature is lowered from 60°C to 30°C, the volume of a fixed amount of gas will be one half
the original volume.
3) A gas is considered “ideal” if one mole of it in a one-liter container exerts a pressure of exactly 1 atm
at room temperature.
4) Kinetic-molecular theory assumes that attractive and repulsive forces between gas particles are
stronger than those between gas particles and container walls.
5) According to the kinetic-molecular theory, molecules of different gases at the same temperature
always have the same average kinetic energy.
6) The effusion rate of a gas is proportional to the square root of its molar mass.
7) Two deviations of real gases from ideal gases which are treated in the van der Waals equation are
finite molecular volume and non-zero molecular attractions.