Chemistry 151 – Sample Exam 3 (M/C Part)
Note: I have added several (~8) extra problems from Chapter 5 so you can get more practice on
the types of numerical questions that show up for gases.
1.
A pressure that will support a column of Hg to a height of 256 mm would support a column
of water to what height? The density of mercury is 13.6 g/cm3.
A.
B.
C.
D.
E.
2.
348 cm
1.00 × 102 ft
18.8 mm
33.8 ft
76.0 cm
The gas pressure in an aerosol can is 1.8 atm at 25C. If the gas is an ideal gas, what
pressure would develop in the can if it were heated to 475C?
A. 0.095 atm
3.
C. 1/2
D. 1/4
E. 1/8
B. 3/4
C. 4/3
D. 1/3
E. 4
B. 6.2 mL
C. 7.1 mL
D. 22.4 mL
E. 41.4 mL
B. 1.35 atm
C. 8.8 atm
D. 0.738 atm
E. 0.114 atm
0.820 mole of hydrogen gas has a volume of 2.00 L at a certain temperature and pressure.
What is the volume 0.125 mol of this gas at the same temperature and pressure?
A. 0.0512 L
8.
B. 2
The temperature of an ideal gas in a 5.00 L container originally at 1 atm pressure and 25C
is lowered to 220 K. Calculate the new pressure of the gas.
A. 1.0 atm
7.
E. 34.2 atm
A small bubble rises from the bottom of a lake, where the temperature and pressure are 4C
and 3.0 atm, to the water's surface, where the temperature is 25C and pressure is 0.95 atm.
Calculate the final volume of the bubble if its initial volume was 2.1 mL.
A. 0.72 mL
6.
D. 4.52 atm
If the pressure on a gas sample is tripled and the absolute temperature is quadrupled, by
what factor will the volume of the sample change?
A. 12
5.
C. 3.26 atm
If the pressure of a gas sample is quadrupled and the absolute temperature is doubled, by
what factor does the volume of the sample change?
A. 8
4.
B. 0.717 atm
B. 0.250 L
C. 0.305 L
D. 4.01 L
E. 19.5 L
Calculate the volume occupied by 35.2 g of methane gas (CH4) at 25C and 1.0 atm.
R = 0.0821 L atm/Kmol.
A. 0.0186 L
B. 4.5 L
C. 11.2 L
Page 1
D. 49.2 L
E. 53.7 L
9.
Gases are sold in large cylinders for laboratory use. What pressure, in atmospheres, will be
exerted by 2,500 g of oxygen gas (O2) when stored at 22C in a 40.0 L cylinder?
A.
B.
C.
D.
E.
10.
3.55 atm
1,510 atm
47.3 atm
7.56 × 104 atm
10.2 atm
Calculate the density of CO2(g) at 100C and 10.0 atm pressure.
A. 1.44 g/L
11.
C. -39.3 g/L
D. 39.95 g/L
E. 1254 g/L
B. CClF3
C. CO2
D. C2H6
E. CF4
Determine the molar mass of Freon-11 gas if a sample weighing 0.597 g occupies 100 cm3
at
95C, and 1,000 mmHg.
B. 35.3 g/mol
C. 70.9 g/mol
D. 137 g/mol
E. 384 g/mol
A mixture of three gases has a total pressure of 1,380 mmHg at 298 K. The mixture is
analyzed and is found to contain 1.27 mol CO2, 3.04 mol CO, and 1.50 mol Ar. What is
the partial pressure of Ar?
A. 0.258 atm
16.
B. 1.65 g/L
increases.
decreases.
remains the same.
Not enough information is given to correctly answer the question.
A. 0.19 g/mol
15.
E. 14.4 g/L
Two moles of chlorine gas at 20.0C are heated to 350C while the volume is kept
constant. The density of the gas
A.
B.
C.
D.
14.
D. 53.6 g/L
Which of the following gases will have the greatest density at the same specified
temperature and pressure?
A. H2
13.
C. 44.0 g/L
Calculate the density of Ar(g) at -11C and 675 mmHg.
A. 1.52 g/L
12.
B. 134 g/L
B. 301 mmHg
C. 356 mmHg
D. 5,345 mmHg E. 8,020 mmHg
How many liters of chlorine gas at 200C and 0.500 atm can be produced by the reaction
of 12.0 g of MnO2 with HCl as follows?
MnO2(s) + 4HCl(aq)  MnCl2(aq) + 2H2O(l) + Cl2(g)
A. 10.7 L
B. 3.09 L
C. 4.53 L
Page 2
D. 0.138 L
E. 0.093 L
17.
Chlorine gas can be prepared in the laboratory by the reaction of manganese dioxide with
hydrochloric acid:
MnO2(s) + 4HCl(aq) MnCl2(aq) + 2H2O(l) + Cl2(g)
How much MnO2 should be added to excess HCl to obtain 275 mL of chlorine gas at
5.0C and 650 mmHg?
A.
B.
C.
D.
E.
18.
1.18 × 10–4 g
0.896 g
1.22 g
49.8 g
8,440 g
What mass of KClO3 must be decomposed to produce 126 L of oxygen gas at 133C and
0.880 atm?
2KClO3(s) 2KCl(s) + 3O2(g)
A. 24.6 g
19.
B. 70.8 g
C. 272 g
D. 408 g
E. 612 g
Which statement is false?
A. The average kinetic energies of molecules from samples of different "ideal" gases is the
same at the same temperature.
B. The molecules of an ideal gas are relatively far apart.
C. All molecules of an ideal gas have the same kinetic energy at constant temperature.
D. Molecules of a gas undergo many collisions with each other and the container walls.
E. Molecules of greater mass have a lower average speed than those of less mass at the
same temperature.
20.
Complete this sentence: The molecules of different samples of an ideal gas have the same
average kinetic energies, at the same ________.
A.
B.
C.
D.
21.
If equal masses of O2(g) and HBr(g) are in separate containers of equal volume and
temperature, which one of the following statements is true?
A.
B.
C.
D.
E.
22.
pressure
temperature
volume
density
The pressure in the O2 container is greater than that in the HBr container.
There are more HBr molecules than O2 molecules.
The average velocity of the O2 molecules is less than that of the HBr molecules.
The average kinetic energy of HBr molecules is greater than that of O2 molecules.
The pressures of both gases are the same.
Which gas has molecules with the greatest average molecular speed at 25C?
A. CH4
B. Kr
C. N2
Page 3
D. CO2
E. Ar
23.
Which of the following gas molecules have the highest average kinetic energy at 25C?
A.
B.
C.
D.
E.
24.
H2
O2
N2
Cl2
All the gases have the same average kinetic energy.
What is the pressure of the gas trapped in the apparatus shown below when the atmospheric
pressure is 720 mmHg?
A. 12 mmHg
25.
C. 720 mmHg
D. 732 mmHg
E. 760 mmHg
Determine the pressure of the gas trapped in the apparatus shown below when the
atmospheric pressure is 695 mmHg.
A. 45 mmHg
26.
B. 708 mmHg
B. 650 mmHg
C. 695 mmHg
D. 740 mmHg
E. 760 mmHg
Copper metal has a specific heat of 0.385 J/gC. Calculate the amount of heat required to
raise the temperature of 22.8 g of Cu from 20.0C to 875C.
A. 1.97 10–5 J B. 1.0 10–2 J
C. 329 J
Page 4
D. 7.51 kJ
E. 10.5 kJ
27.
A glass containing 200 g of H2O at 20C was placed in a refrigerator. The water loses
11.7 kJ as it cools to a constant temperature. What is its new temperature? The specific
heat of water is 4.184 J/gC.
A. 0.013C
28.
D. 14C
32.9 kJ/C
7.8 kJ/C
1.76 kJ/C
1.76 kJ/C
15.3 kJ/C
O2(g) + 2H2(g)  2H2O(g)
H2O(g) H2O(l)
3O2(g) + 2CH3OH(g) 2CO2(g) + 2H2O(g)
H2O(s) H2O(l)
Find the standard enthalpy of formation of ethylene, C2H4(g), given the following data:
C2H4(g) + 3O2(g) 2CO2(g) + 2H2O(l)
C(s) + O2(g) CO2(g)
H2(g) + 1/2O2(g) H2O(l)
A.
B.
C.
D.
E.
31.
E. 34C
Which of the following processes is endothermic?
A.
B.
C.
D.
30.
C. 6C
Naphthalene combustion can be used to calibrate the heat capacity of a bomb calorimeter.
The heat of combustion of naphthalene is 40.1 kJ/g. When 0.8210 g of naphthalene was
burned in a calorimeter containing 1,000 g of water, a temperature rise of 4.21C was
observed. What is the heat capacity of the bomb calorimeter excluding the water?
A.
B.
C.
D.
E.
29.
B. 4C
Hf = -1411 kJ
Hf = -393.5 kJ
Hf = -285.8 kJ
52 kJ
87 kJ
731 kJ
1.41 103 kJ
2.77 103 kJ
Given the thermochemical equation
2SO2 + O2 2SO3
Hrxn = -198 kJ.
What is the enthalpy change (H) for the decomposition of one mole of SO3?
A. 198 kJ
B. -99 kJ
C. 99 kJ
Page 5
D. 396 kJ
E. -198 kJ
32.
The combustion of octane produces heat according to the equation
2C8H18(l) + 25O2(g) 16CO2(g) + 18H2O(l)
Hrxn= -11,020 kJ
What is the heat of combustion per gram of octane?
A.
B.
C.
D.
E.
33.
-5.510 MJ/g
-96.5 kJ/g
-48.2 kJ/g
-193 kJ/g
-629.2 MJ/g
The combustion of butane produces heat according to the equation
2C4H10(g) + 13O2(g) 8CO2(g) + 10H2O(l)
Hrxn= -5,314 kJ
How many grams of CO2 are produced per 1.00 104 kJ of heat released?
A.
B.
C.
D.
E.
23.4 g
44.0 g
82.3 g
187 g
662 g
Page 6
Answer Key for Test "Exam_3_Sample.tst", 11/10/2003
No. in
Q-Bank
5-1
5-7
5-8
5-9
5-10
5-11
5-12
5-15
5-21
5-24
5-28
5-29
5-31
5-34
5-38
5-44
5-46
5-50
5-51
5-52
5-53
5-54
5-55
5-58
5-59
6-3
6-8
6-12
6-13
6-20
6-28
6-33
6-37
No. on
Test
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Correct
Answer
A
D
C
C
C
D
C
E
C
E
B
B
C
D
C
A
B
C
C
B
A
A
E
B
D
D
C
C
D
A
C
C
D
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