Name: ________________________ Class: ___________________ Date: __________
ID: A
Gases SOM PreTest
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1. A gas is ____ and assumes ____ of its container whereas a liquid is ____ and assumes ______ of its container.
a. condensed, the volume and shape, condensed, the volume and shape b. compressible, the shape, not compressible, the volume and shape c. compressible, the volume and shape, not compressible, the shape of a portion d. condensed, the shape, compressible, the volume and shape
2. The tendency of molecules to move toward areas of lower concentration is called
a. suspension. b. effusion. c. suffusion. d. diffusion.
3. It is found that 250. mL of a gas at STP has a mass of 0.700 g. What is the molar mass?
a. 128 g/mol b. 62.7 g/mol c. 2.80 g/mol d. 11.2 g/mol
4. What causes a gas to exert pressure?
a. temperature b. collisions c. density d. elevation
5. A sample of N2 gas is contaminated with a gas (A) of unknown molar mass. It is found that gas A escapes
at 4 times the rate of N2 . The molar mass of gas A is:
a. 112 g/mol b. 1.75 g/mol c. 448 g/mol d. 7.01 g/mol
6. A sample consisting of CO2(g) and CO2(s) at equilibrium at –78°C and 1 atm pressure is heated to –30°C
and the pressure is increased to 8 atm. Based on the phase diagram below, what will happen?
a. All of the CO2 will be converted to CO2(l). b. The melting point of the CO2(s) will decrease. c. At
equilibrium, only CO2(g) will be present. d. At equilibrium, CO2(g) and CO2(l) will be present.
7. The partial pressures of CH4 , N2, and O2 in a sample of gas were found to be 135 mmHg, 508 mmHg, and
571 mmHg, respectively. Calculate the mole fraction of nitrogen.
a. 0.751 b. 0.470 c. 20.4 d. 0.418
8. A balloon has a volume of 2.32 liters at 24.0°C. The balloon is heated to 48.0°C. Calculate the new
volume of the balloon.
a. 4.64 L b. 2.15 L c. 2.51 L d. 1.16 L
9. Which of the following would have a higher rate of effusion than C2 H2?
a. CH4 b. N2 c. Cl2 d. O2
10. A breathing mixture used by deep-sea divers contains helium, oxygen, and carbon dioxide. What is the partial
pressure of oxygen at 101.4 kPa if P He = 82.5 kPa and P CO 2 = 0.4 kPa?
a. 18.5 kPa b. 101.0 kPa c. 82.9 kPa d. 19.3 kPa
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Name: ________________________
ID: A
Use the table below to answer the following questions.
Water Vapor Pressure
Pressure (mm Hg)
Temperature (C)
0
4.6
5
6.5
10
9.2
15
12.8
20
17.5
25
23.8
30
31.8
35
42.2
40
55.3
50
92.5
11. A sample of gas is collected by water displacement at 400.0 mm Hg and 30C. What is the gas’ partial pressure?
a. 368.2 mm Hg b. 431.8 mm Hg c. 430 mm Hg d. 400.0 mm Hg
12. The temperature of a specific amount of gas in a sealed container changes from 20.0°C to 40.0°C. If the
volume remains constant, the pressure will change from 755 mmHg to
a. 807 mmHg b. 1510 mmHg c. 378 mmHg d. 707 mmHg
13. An ideal gas is a hypothetical gas
a. whose particles have zero mass. b. made of motionless particles. c. that conforms to all of the assumptions
of the kinetic theory. d. not made of particles.
14. Which of the following is a Potential Energy Change?
a. CD b. AB c. BC d. EF
15. The heating curve shown was generated by measuring the heat flow and temperature for a solid as it was heated. The
slope of the __________ segment corresponds to the heat capacity of the liquid of the substance.
a. DE b. BC c. AB d. CD
16. The heating curve shown was generated by measuring the heat flow and temperature of a solid as it was heated. The
heat flow into the sample in the segment __________ will yield the value of the Hvap of this substance.
a. AB b. BC c. CD d. DE e. EF
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Name: ________________________
ID: A
17. Which of the compounds below is an example of a network solid?
a. SiO2(s) b. MgO(s) c. C25H52(s) d. S8 (s)
18.
a.
b.
Which graph illustrates Boyle’s law?
Volume Vs. Pressure for a
Gas at Constant Temperature
Pressure Vs. Temperature for a
Gas at Constant Volume
c.
Pressure Vs. Temperature for a
Gas at Constant Volume
d.
Volume vs. Pressure for a
Gas at Constant Temperature
Three identical 1.0-L flasks contain the gases He, CH4, and NH3, each at 0°C and 1 atm pressure.
19. For which gas do the molecules have the highest average velocity?
a. CH4 b. NH3 c. all gases the same d. He
20. For which gas do the molecules have the smallest average kinetic energy?
a. all gases the same b. NH3 c. He d. CH4
21. Diffusion between two gases occurs most rapidly if the gases are at
a. low temperature and the molecules are large. b. high temperature and the molecules are large. c. high
temperature and the molecules are small. d. low temperature and the molecules are small.
22. The strongest interparticle attractions exist between particles of a __________ and the weakest interparticle
attractions exist between particles of a __________.
a. liquid, solid b. solid, gas c. gas, solid d. solid, liquid
23. For a gas, which two variables are directly proportional to each other (if all other conditions remain
constant)? 1. P and V
2. P and n
a. 1 only b. 2 only c. 2 and 3 only d. 3 only
3. P and T
24. When a container is filled with 3.00 moles of H2, 2.00 moles of O2, and 1.00 mole of N2, the pressure in the
container is 768 kPa. What is the partial pressure of O2?
a. 256 kPa b. 128 kPa c. 192 kPa d. 128 kPa
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Name: ________________________
ID: A
25. A volatile liquid
a. has no odor. b. is ionic. c. evaporates readily. d. has strong attractive forces between particles.
26. Crystalline solids __________.
a. exist only at high temperatures b. have highly ordered structures c. exist only at very low temperatures d. are usually very soft
27.
The normal boiling point of the substance with the phase diagram shown above is __________°C.
a. 10 b. 15 c. 30 d. 40
28. Under which conditions do real gases most resemble ideal gases?
a. high pressure and high temperature b. low pressure and high temperature c. low pressure and low
temperature d. high pressure and low temperature
29. Which of the following is not a type of crystal?
a. ionic crystal b. lattice crystal c. metallic crystal d. covalent network crystal
30. The equilibrium vapor pressure of a liquid is
a. the same for all liquids. b. measured only at 0C. c. constant for a particular liquid at all temperatures.
d. the pressure exerted by a vapor in equilibrium with its liquid at a given temperature.
31. According to the kinetic-molecular theory, gases condense into liquids because of
a. forces between molecules. b. elastic collisions. c. atmospheric pressure. d. gravity.
32. A sample of gas occupies 17 mL at –112C. Assuming the pressure is held constant, what volume does the sample
occupy at 70C?
a. 27 mL b. 8.0mL c. 10.6 mL d. 36mL
33. A 3.60-L sample of carbon monoxide is collected at 55°C and 0.869 atm. What volume will the gas
occupy at 1.05 atm and 25°C?
a. 1.35 L b. 3.95 L c. 3.28 L d. 2.71 L e. none of these
34. A gas sample is heated from -20.0°C to 57.0°C and the volume is increased from 2.00 L to 4.50 L. If the
initial pressure is 0.140 atm, what is the final pressure?
a. 0.411 atm b. 0.242 atm c. 0.0811 atm d. 0.0477 atm
35. A 7.94-g piece of solid CO2 (dry ice) is allowed to sublime in a balloon. The final volume of the balloon is
1.00 L at 301 K. What is the pressure of the gas?
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a. 0.224 atm b. 4.46 atm c. 3.11 atm d. 1.96  10 atm e. none of these
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Name: ________________________
ID: A
Diagram- you will put these into the TI Tomorrow
1. Triple point
2. Critical point
3. Gas
4. Liquid
5. Solid
6. Normal freezing point
7. On the phase diagram shown above, segment __________ corresponds to the conditions of temperature and pressure
under which the liquid and the gas of the substance are in equilibrium.
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