# The Kinetic Theory of Gases - Chapter No 17

Right Answers have been shown below in red color.

1. Evidence that a gas consists mostly of empty space is the fact that:

A. the density of a gas becomes much greater when it is liquefied
B. gases exert pressure on the walls of their containers
C. gases are transparent
D. heating a gas increases the molecular motion
E. nature abhors a vacuum

2. Air enters a hot-air furnace at 7◦ C and leaves at 77◦ C. If the pressure does not change each entering cubic meter of air expands to:

A. 0.80 m3
B. 1.25 m3
C. 1.9 m3
D. 7.0 m3
E. 11 m3

3. 273 cm3 of an ideal gas is at 0◦ C. It is heated at constant pressure to 10◦ C. It will now occupy:

A. 263 cm3
B. 273 cm3
C. 283 cm3
D. 278 cm3
E. 293 cm3

4. Two identical rooms in a house are connected by an open doorway. The temperatures in the two rooms are maintained at different values. Which room contains more air?

A. the room with higher temperature
B. the room with lower temperature
C. the room with higher pressure
D. neither because both have the same pressure
E. neither because both have the same volume

5. It is known that 28 g of a certain ideal gas occupies 22.4 liters at standard conditions (0◦ C, 1 atm). The volume occupied by 42 g of this gas at standard conditions is:

A. 14.9 liters
B. 22.4 liters
C. 33.6 liters
D. 42 liters
E. more data are needed

6. An automobile tire is pumped up to a gauge pressure of 2.0 × 105 Pa when the temperature is 27◦ C. What is its gauge pressure after the car has been running on a hot day so that the tire temperature is 77◦ C? Assume that the volume remains fixed and take atmospheric pressure to be 1.013 × 105 Pa.

A. 1.6 × 105 Pa
B. 2.6 × 105 Pa
C. 3.6 × 105 Pa
D. 5.9 × 105 Pa
E. 7.9 × 105 Pa

7. A sample of an ideal gas is compressed by a piston from 10 m3 to 5 m3 and simultaneously cooled from 273◦ C to 0◦ C. As a result, there is:

A. an increase in pressure
B. a decrease in pressure
C. a decrease in density
D. no change in density
E. an increase in density

8. A 2-m3 weather balloon is loosely filled with helium at 1 atm (76 cm Hg) and at 27◦ C. At an elevation of 20, 000 ft, the atmospheric pressure is down to 38 cm Hg and the helium has expanded, being under no constraint from the confining bag. If the temperature at this elevation is -48◦ C, the gas volume (in m3) is:

A. 3
B. 4
C. 2
D. 2.5
E. 5.3

9. Oxygen (molar mass = 32 g) occupies a volume of 12 liters when its temperature is 20◦ C and its pressure is 1 atm. Using R = 0.082 liters · atm/mol · K, calculate the mass of the oxygen:

A. 6.4 g
B. 10. g7
C. 16 g
D. 32 g
E. 64 g

10. An ideal gas occupies 12 liters at 293 K and 1 atm (76 cm Hg). Its temperature is now raised to 373 K and its pressure increased to 215 cm Hg. The new volume is:

A. 0.2 liters
B. 5.4 liters
C. 13.6 liters
D. 20.8 liters
E. none of these

11. Use R = 8.2 × 10−5 m3 · atm/mol · K and NA = 6.02 × 1023 mol−1 . The approximate number of air molecules in a 1 m3 volume at room temperature (300 K and atmospheric pressure is:

A. 41
B. 450
C. 2.5 × 1025
D. 2.7 × 1026
E. 5.4 × 1026

12. An air bubble doubles in volume as it rises from the bottom of a lake (1000 kg/m3). Ignoring any temperature changes, the depth of the lake is:
A. 21 m B. 0.76 m C. 4.9 m D. 10 m E. 0.99 m

13. An isothermal process for an ideal gas is represented on a p-V diagram by:

A. a horizontal line
B. a vertical line
C. a portion of an ellipse
D. a portion of a parabola
E. a portion of a hyperbola

14. An ideal gas undergoes an isothermal process starting with a pressure of 2 × 105 Pa and a volume of 6 cm3. Which of the following might be the pressure and volume of the final state?

A. 1 × 105 Pa and 10 cm3
B. 3 × 105 Pa and 6 cm3
C. 4 × 105 Pa and 4 cm3
D. 6 × 105 Pa and 2 cm3
E. 8 × 105 Pa and 2 cm3

15. The pressures p and volumes V of five ideal gases, with the same number of molecules, are given below. Which has the highest temperature?

A. p = 1 × 105 Pa and V = 10 cm3
B. p = 3 × 105 Pa and V = 6 cm3
C. p = 4 × 105 3 Pa and V = 4 cm3
D. p = 6 × 105 Pa and V = 2 cm3
E. p = 8 × 105 Pa and V = 2 cm3

16. During a slow adiabatic expansion of a gas:

A. the pressure remains constant
B. energy is added as heat
C. work is done on the gas
D. no energy enters or leaves as heat
E. the temperature is constant

17. An adiabatic process for an ideal gas is represented on a p-V diagram by:

A. a horizontal line
B. a vertical line
C. a hyperbola
D. a circle
E. none of these

18. A real gas undergoes a process that can be represented as a curve on a p-V diagram. The work done by the gas during this process is:

A. pV
B. p(V2 − V1)
C. (p2 − p1)V
D. ∫ p dV
E. V dp

19. A real gas is changed slowly from state 1 to state 2. During this process, no work is done on or by the gas. This process must be:

A. isothermal