Question 1

An ideal monatomic gas has a molar specific heat Cv at constant volume of:

Accepted Answer

A)  R 
B)  3R/2 
C)  5R/2 
D)  7R/2 
E)  9R/2 
A)  R 
B)  3R/2 
C)  5R/2 
D)  7R/2 
E)  9R/2

Question 2

The number of degrees of freedom of a rigid diatomic molecule is:

Accepted Answer

A)  2 
B)  3 
C)  4 
D)  5 
E)  6 
A)  2 
B)  3 
C)  4 
D)  5 
E)  6

Question 3

The energy absorbed as heat by an ideal gas for an isothermal process equals:

Accepted Answer

A)  the work done by the gas 
B)  the work done on the gas 
C)  the change in the internal energy of the gas 
D)  the negative of the change in internal energy of the gas 
E)  zero since the process is isothermal 
A)  the work done by the gas 
B)  the work done on the gas 
C)  the change in the internal energy of the gas 
D)  the negative of the change in internal energy of the gas 
E)  zero since the process is isothermal

Question 4

The pressure of an ideal gas is doubled during a process in which the energy given up as heat by the gas equals the work done on the gas. As a result, the volume is:

Accepted Answer

A)  doubled 
B)  halved 
C)  unchanged 
D)  need more information to answer 
E)  nonsense, the process is impossible 
A)  doubled 
B)  halved 
C)  unchanged 
D)  need more information to answer 
E)  nonsense, the process is impossible

Question 5

A system consists of N gas molecules, each with mass m. Their rms speed is vrms. Their total translational kinetic energy is:

Accepted Answer

A)  (1/2)m(Nvrms)2 
B)  (1/2)N(mvrms)2 
C)  (1/2)mv2rms 
D)  (1/2)Nmv2rms 
E)  N[(1/2)mvrms]2 
A)  (1/2)m(Nvrms)2 
B)  (1/2)N(mvrms)2 
C)  (1/2)mv2rms 
D)  (1/2)Nmv2rms 
E)  N[(1/2)mvrms]2

Question 6

The speeds of 25 molecules are distributed as follows: 5 in the range from 2 to 3 m/s, 10 in the range from 3 to 4 m/s, 5 in the range from 4 to 5 m/s, 3 in the range from 5 to 6 m/s, 1 in the range from 6 to 7 m/s, and 1 in the range from 7 to 8 m/s. Their average speed is about:

Accepted Answer

A)  2 m/s 
B)  3 m/s 
C)  4 m/s 
D)  5 m/s 
E)  6 m/s 
A)  2 m/s 
B)  3 m/s 
C)  4 m/s 
D)  5 m/s 
E)  6 m/s

Question 7

A certain ideal gas has a temperature 300 K and a pressure 5.0 *104 Pa. The molecules have a mean free path of 4.0 *10-7m. If the temperature is raised to 350 K and the pressure is reduced to 1.0 * 104 Pa the mean free path is them:

Accepted Answer

A)  6.9 * 10-8m 
B)  9.3 *10 - 8m 
C)  3.3 * 10 -7m 
D)  1.7 *10-6m 
E)  2.3 *10-6m 
A)  6.9 * 10-8m 
B)  9.3 *10 - 8m 
C)  3.3 * 10 -7m 
D)  1.7 *10-6m 
E)  2.3 *10-6m

Question 8

The mean free path of molecules in a gas is proportional to:

Accepted Answer

A)  the molecular diameter 
B)  the reciprocal of the molecular diameter 
C)  the molecular concentration 
D)  the reciprocal of the molecular concentration 
E)  the average molecular speed 
A)  the molecular diameter 
B)  the reciprocal of the molecular diameter 
C)  the molecular concentration 
D)  the reciprocal of the molecular concentration 
E)  the average molecular speed

Question 9

The rms speed of an oxygen molecule at 0 $\degree$C is 460 m/s. If the molar mass of oxygen is 32 g and of helium is 4 g, then the rms speed of a helium molecule at 0 $\degree$C is:

Accepted Answer

A)  230 m/s 
B)  326 m/s 
C)  650 m/s 
D)  920 m/s 
E)  1300 m/s 
A)  230 m/s 
B)  326 m/s 
C)  650 m/s 
D)  920 m/s 
E)  1300 m/s

Question 10

The temperature of low pressure hydrogen is reduced from 100 $\degree$C to 20 $\degree$C. The rms speed of its molecules decreases by approximately:

Accepted Answer

A)  80% 
B)  89% 
C)  46% 
D)  21% 
E)  11% 
A)  80% 
B)  89% 
C)  46% 
D)  21% 
E)  11%

Question 11

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

Accepted Answer

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

Question 12

Two monatomic ideal gases are in thermal equilibrium with each other. Gas A is composed of molecules with mass m while gas B is composed of molecules with mass 4m. The ratio of the average molecular kinetic energy KA/KB is:

Accepted Answer

A)  1/4 
B)  1/2 
C)  1 
D)  2 
E)  4 
A)  1/4 
B)  1/2 
C)  1 
D)  2 
E)  4

Question 13

The temperature of a gas is most closely related to:

Accepted Answer

A)  the kinetic energy of translation of its molecules 
B)  its total molecular kinetic energy 
C)  the sizes of its molecules 
D)  the potential energy of its molecules 
E)  the total energy of its molecules 
A)  the kinetic energy of translation of its molecules 
B)  its total molecular kinetic energy 
C)  the sizes of its molecules 
D)  the potential energy of its molecules 
E)  the total energy of its molecules

Question 14

The "Principle of equipartition of energy" states that the internal energy of a gas is shared equally:

Accepted Answer

A)  among the molecules 
B)  between kinetic and potential energy 
C)  among the relevant degrees of freedom 
D)  between translational and vibrational kinetic energy 
E)  between temperature and pressure 
A)  among the molecules 
B)  between kinetic and potential energy 
C)  among the relevant degrees of freedom 
D)  between translational and vibrational kinetic energy 
E)  between temperature and pressure

Question 15

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:

Accepted Answer

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

Question 16

Ideal monatomic gas A is composed of molecules with mass m while ideal monatomic gas B is composed of molecules with mass 4m. The average molecular energies are the same if the ratio of the temperatures TA/TB is:

Accepted Answer

A)  1/4 
B)  1/2 
C)  1 
D)  2 
E)  4 
A)  1/4 
B)  1/2 
C)  1 
D)  2 
E)  4

Question 17

When work W is done on an ideal gas of diatomic molecules in thermal isolation the increase in the total rotational energy of the molecules is:

Accepted Answer

A)  0 
B)  W/3 
C)  2W/3 
D)  2W/5 
E)  W 
A)  0 
B)  W/3 
C)  2W/3 
D)  2W/5 
E)  W

Question 18

During a reversible adiabatic expansion of an ideal gas, which of the following is NOT true?

Accepted Answer

A)    
B)  pV = nRT 
C)    
D)  W = -$\int$ pdV 
E)  pV = constant 
A)    
B)  pV = nRT 
C)    
D)  W = -$\int$ pdV 
E)  pV = constant

Question 19

Which of the following changes when the pressure of an ideal gas is changed isothermally?

Accepted Answer

A)  Mean free path 
B)  Root-mean-square molecular speed 
C)  Internal energy 
D)  Most probable kinetic energy 
E)  Average speed 
A)  Mean free path 
B)  Root-mean-square molecular speed 
C)  Internal energy 
D)  Most probable kinetic energy 
E)  Average speed

Question 20

Two ideal monatomic gases are in thermal equilibrium with each other. Gas A is composed of molecules with mass m while gas B is composed of molecules with mass 4m. The ratio of the average molecular speeds vA/vB is:

Accepted Answer

A)  1/4 
B)  1/2 
C)  1 
D)  2 
E)  4 
A)  1/4 
B)  1/2 
C)  1 
D)  2 
E)  4

Exam 19: The Kinetic Theory of Gases

An ideal monatomic gas has a molar specific heat Cv at constant volume of:

The number of degrees of freedom of a rigid diatomic molecule is:

The energy absorbed as heat by an ideal gas for an isothermal process equals:

The pressure of an ideal gas is doubled during a process in which the energy given up as heat by the gas equals the work done on the gas. As a result, the volume is:

A system consists of N gas molecules, each with mass m. Their rms speed is vrms. Their total translational kinetic energy is:

The speeds of 25 molecules are distributed as follows: 5 in the range from 2 to 3 m/s, 10 in the range from 3 to 4 m/s, 5 in the range from 4 to 5 m/s, 3 in the range from 5 to 6 m/s, 1 in the range from 6 to 7 m/s, and 1 in the range from 7 to 8 m/s. Their average speed is about:

A certain ideal gas has a temperature 300 K and a pressure 5.0 *104 Pa. The molecules have a mean free path of 4.0 *10-7m. If the temperature is raised to 350 K and the pressure is reduced to 1.0 * 104 Pa the mean free path is them:

The mean free path of molecules in a gas is proportional to:

The rms speed of an oxygen molecule at 0 °\degree° C is 460 m/s. If the molar mass of oxygen is 32 g and of helium is 4 g, then the rms speed of a helium molecule at 0 °\degree° C is:

The temperature of low pressure hydrogen is reduced from 100 °\degree° C to 20 °\degree° C. The rms speed of its molecules decreases by approximately:

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

Two monatomic ideal gases are in thermal equilibrium with each other. Gas A is composed of molecules with mass m while gas B is composed of molecules with mass 4m. The ratio of the average molecular kinetic energy KA/KB is:

The temperature of a gas is most closely related to:

The "Principle of equipartition of energy" states that the internal energy of a gas is shared equally:

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:

Ideal monatomic gas A is composed of molecules with mass m while ideal monatomic gas B is composed of molecules with mass 4m. The average molecular energies are the same if the ratio of the temperatures TA/TB is:

When work W is done on an ideal gas of diatomic molecules in thermal isolation the increase in the total rotational energy of the molecules is:

During a reversible adiabatic expansion of an ideal gas, which of the following is NOT true?

Which of the following changes when the pressure of an ideal gas is changed isothermally?

Two ideal monatomic gases are in thermal equilibrium with each other. Gas A is composed of molecules with mass m while gas B is composed of molecules with mass 4m. The ratio of the average molecular speeds vA/vB is:

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An ideal monatomic gas has a molar specific heat C_v at constant volume of:

A system consists of N gas molecules, each with mass m. Their rms speed is v_rms. Their total translational kinetic energy is:

A certain ideal gas has a temperature 300 K and a pressure 5.0 10⁴Pa. The molecules have a mean free path of 4.0 10^-⁷m. If the temperature is raised to 350 K and the pressure is reduced to 1.0 * 10⁴Pa the mean free path is them:

The rms speed of an oxygen molecule at 0 $\degree$ C is 460 m/s. If the molar mass of oxygen is 32 g and of helium is 4 g, then the rms speed of a helium molecule at 0 $\degree$ C is:

The temperature of low pressure hydrogen is reduced from 100 $\degree$ C to 20 $\degree$ C. The rms speed of its molecules decreases by approximately:

Two monatomic ideal gases are in thermal equilibrium with each other. Gas A is composed of molecules with mass m while gas B is composed of molecules with mass 4m. The ratio of the average molecular kinetic energy K_A/K_B is:

Ideal monatomic gas A is composed of molecules with mass m while ideal monatomic gas B is composed of molecules with mass 4m. The average molecular energies are the same if the ratio of the temperatures T_A/T_B is:

Two ideal monatomic gases are in thermal equilibrium with each other. Gas A is composed of molecules with mass m while gas B is composed of molecules with mass 4m. The ratio of the average molecular speeds v_A/v_B is: