Question 1

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 2

The pressure of an ideal gas is doubled in an isothermal process.The root-mean-square speed of the molecules:

Accepted Answer

A) does not change 
B) increases by a factor of 
C) decreases by a factor of 
D) increases by a factor of 2 
E) decreases by a factor of 1/2 
A) does not change 
B) increases by a factor of 
C) decreases by a factor of 
D) increases by a factor of 2 
E) decreases by a factor of 1/2

Question 3

Energy transferred into an ideal gas as heat:

Accepted Answer

A) goes entirely into the internal energy of the gas 
B) goes entirely into doing work to expand the gas 
C) goes entirely into the internal energy of the gas only if the pressure is constant 
D) goes entirely into the internal energy of the gas only if the temperature is constant 
E) goes entirely into the internal energy of the gas only if the volume is constant 
A) goes entirely into the internal energy of the gas 
B) goes entirely into doing work to expand the gas 
C) goes entirely into the internal energy of the gas only if the pressure is constant 
D) goes entirely into the internal energy of the gas only if the temperature is constant 
E) goes entirely into the internal energy of the gas only if the volume is constant

Question 4

The diagram shows three isotherms for an ideal gas, with T3-T2 the same as T2-T1.It also shows five thermodynamic processes carried out on the gas.Rank the processes in order of the change in the internal energy of the gas, least to greatest.

Accepted Answer

A) I, II, III, IV, V 
B) V; then I, III and IV tied; then II 
C) V; I; then III, and IV tied; then II 
D) II; then I, III and IV tied; then V 
E) II; I; then III, IV, and V tied 
A) I, II, III, IV, V 
B) V; then I, III and IV tied; then II 
C) V; I; then III, and IV tied; then II 
D) II; then I, III and IV tied; then V 
E) II; I; then III, IV, and V tied

Question 5

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

Accepted Answer

A) "pV" 
B) "p(V2 - V1)" 
C) "(p2 - p1)V" 
D) "$\int$ p dV" 
E) "V dp" 
A) "pV" 
B) "p(V2 - V1)" 
C) "(p2 - p1)V" 
D) "$\int$ p dV" 
E) "V dp"

Question 6

The temperature of n moles of an ideal monatomic gas is increased by $\Delta$T at constant pressure.The energy Q absorbed as heat, change $\Delta$Eint in internal energy, and work W done by the environment are given by:

Accepted Answer

A) Q = (5/2)nR$\Delta$T, $\Delta$Eint = 0, W = -nR$\Delta$T 
B) Q = (3/2)nR$\Delta$T, $\Delta$Eint = (5/2)nR$\Delta$T, W = -(3/2)nR$\Delta$T 
C) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (5/2)nR$\Delta$T, W = 0 
D) Q = (3/2)nR$\Delta$T, $\Delta$Eint = 0, W = -nR$\Delta$T 
E) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (3/2)nR$\Delta$T, W = -nR$\Delta$T 
A) Q = (5/2)nR$\Delta$T, $\Delta$Eint = 0, W = -nR$\Delta$T 
B) Q = (3/2)nR$\Delta$T, $\Delta$Eint = (5/2)nR$\Delta$T, W = -(3/2)nR$\Delta$T 
C) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (5/2)nR$\Delta$T, W = 0 
D) Q = (3/2)nR$\Delta$T, $\Delta$Eint = 0, W = -nR$\Delta$T 
E) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (3/2)nR$\Delta$T, W = -nR$\Delta$T

Question 7

How many molecules are in a sample of 10-3 mol?

Accepted Answer

A) 6.02 x 1018 
B) 6.02 x 1020 
C) 6.02 x 1022 
D) 6.02 x 1023 
E) cannot tell without knowing the molecular mass 
A) 6.02 x 1018 
B) 6.02 x 1020 
C) 6.02 x 1022 
D) 6.02 x 1023 
E) cannot tell without knowing the molecular mass

Question 8

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 9

A gas is confined to a cylindrical container of radius 1 cm and length 1 m.The pressure exerted on an end face, compared with the pressure exerted on the long curved face, is:

Accepted Answer

A) smaller because its area is smaller 
B) smaller because most molecules cannot traverse the length of the cylinder without undergoing collisions 
C) larger because the face is flat 
D) larger because the molecules have a greater distance in which to accelerate before they strike the face 
E) none of these 
A) smaller because its area is smaller 
B) smaller because most molecules cannot traverse the length of the cylinder without undergoing collisions 
C) larger because the face is flat 
D) larger because the molecules have a greater distance in which to accelerate before they strike the face 
E) none of these

Question 10

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) 160 m/s 
B) 330 m/s 
C) 650 m/s 
D) 1300 m/s 
E) 3700 m/s 
A) 160 m/s 
B) 330 m/s 
C) 650 m/s 
D) 1300 m/s 
E) 3700 m/s

Question 11

As the pressure in an ideal gas is increased isothermally the average molecular speed:

Accepted Answer

A) increases 
B) decreases 
C) increases at high temperature, decreases at low 
D) decreases at high temperature, increases at low 
E) stays the same 
A) increases 
B) decreases 
C) increases at high temperature, decreases at low 
D) decreases at high temperature, increases at low 
E) stays the same

Question 12

Over 1 cycle of a cyclic process in which a system does net work on its environment:

Accepted Answer

A) the change in the pressure of the system cannot be zero 
B) the change in the volume of the system cannot be zero 
C) the change in the temperature of the system cannot be zero 
D) the change in the internal energy of the system cannot be zero 
E) none of the above 
A) the change in the pressure of the system cannot be zero 
B) the change in the volume of the system cannot be zero 
C) the change in the temperature of the system cannot be zero 
D) the change in the internal energy of the system cannot be zero 
E) none of the above

Question 13

For a gas at thermal equilibrium the average speed v, the most probable speed vp, and the root-mean-square speed vrms are in the order:

Accepted Answer

A) vp rms rms p rms p 
D) vp rms 
E) v p rms 
A) vp rms rms p rms p 
D) vp rms 
E) v p rms

Question 14

As the volume of an ideal gas is increased at constant pressure the average molecular speed:

Accepted Answer

A) increases 
B) decreases 
C) increases at high temperature, decreases at low 
D) decreases at high temperature, increases at low 
E) stays the same 
A) increases 
B) decreases 
C) increases at high temperature, decreases at low 
D) decreases at high temperature, increases at low 
E) stays the same

Question 15

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:

Accepted Answer

A) 41 
B) 450 
C) 2.4 *1025 
D) 2.7 * 1026 
E) 5.4 * 1026 
A) 41 
B) 450 
C) 2.4 *1025 
D) 2.7 * 1026 
E) 5.4 * 1026

Question 16

According to the Maxwellian speed distribution, as the temperature increases the average speed:

Accepted Answer

A) increases 
B) decreases 
C) increases at high temperatures and decreases at low 
D) decreases at high temperatures and increases at low 
E) stays the same 
A) increases 
B) decreases 
C) increases at high temperatures and decreases at low 
D) decreases at high temperatures and increases at low 
E) stays the same

Question 17

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 18

In an adiabatic expansion,

Accepted Answer

A) the temperature of the gas does not change. 
B) the gas does work on the environment, and the internal energy of the gas decreases. 
C) the environment does work on the gas, and the internal energy of the gas increases. 
D) the volume of the gas does not change. 
E) the pressure of the gas does not change. 
A) the temperature of the gas does not change. 
B) the gas does work on the environment, and the internal energy of the gas decreases. 
C) the environment does work on the gas, and the internal energy of the gas increases. 
D) the volume of the gas does not change. 
E) the pressure of the gas does not change.

Question 19

The temperature of n moles of an ideal monatomic gas is increased by $\Delta$T at constant volume.The energy Q absorbed as heat, change $\Delta$Eint in internal energy, and work W done by the environment are given by:

Accepted Answer

A) Q = (5/2)nR$\Delta$T, $\Delta$Eint = 0, W = 0 
B) Q = (3/2)nR$\Delta$T, $\Delta$Eint = (3/2)nR$\Delta$T, W = 0 
C) Q = (3/2)nR$\Delta$T, $\Delta$Eint = (1/2)nR$\Delta$T, W = -nR$\Delta$T 
D) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (3/2)nR$\Delta$T, W = -nR$\Delta$T 
E) Q = (3/2)nR$\Delta$T, $\Delta$Eint = 0, W = -(3/2)nR$\Delta$T 
A) Q = (5/2)nR$\Delta$T, $\Delta$Eint = 0, W = 0 
B) Q = (3/2)nR$\Delta$T, $\Delta$Eint = (3/2)nR$\Delta$T, W = 0 
C) Q = (3/2)nR$\Delta$T, $\Delta$Eint = (1/2)nR$\Delta$T, W = -nR$\Delta$T 
D) Q = (5/2)nR$\Delta$T, $\Delta$Eint = (3/2)nR$\Delta$T, W = -nR$\Delta$T 
E) Q = (3/2)nR$\Delta$T, $\Delta$Eint = 0, W = -(3/2)nR$\Delta$T

Question 20

The number of degrees of freedom of a triatomic molecule is:

Accepted Answer

A) 1 
B) 3 
C) 6 
D) 8 
E) 9 
A) 1 
B) 3 
C) 6 
D) 8 
E) 9

Exam 19: The Kinetic Theory of Gases

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

The pressure of an ideal gas is doubled in an isothermal process.The root-mean-square speed of the molecules:

Energy transferred into an ideal gas as heat:

The diagram shows three isotherms for an ideal gas, with T3-T2 the same as T2-T1.It also shows five thermodynamic processes carried out on the gas.Rank the processes in order of the change in the internal energy of the gas, least to greatest.

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

The temperature of n moles of an ideal monatomic gas is increased by Δ\DeltaΔ T at constant pressure.The energy Q absorbed as heat, change Δ\DeltaΔ Eint in internal energy, and work W done by the environment are given by:

How many molecules are in a sample of 10-3 mol?

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

A gas is confined to a cylindrical container of radius 1 cm and length 1 m.The pressure exerted on an end face, compared with the pressure exerted on the long curved face, is:

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:

As the pressure in an ideal gas is increased isothermally the average molecular speed:

Over 1 cycle of a cyclic process in which a system does net work on its environment:

For a gas at thermal equilibrium the average speed v, the most probable speed vp, and the root-mean-square speed vrms are in the order:

As the volume of an ideal gas is increased at constant pressure the average molecular speed:

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:

According to the Maxwellian speed distribution, as the temperature increases the average speed:

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

In an adiabatic expansion,

The temperature of n moles of an ideal monatomic gas is increased by Δ\DeltaΔ T at constant volume.The energy Q absorbed as heat, change Δ\DeltaΔ Eint in internal energy, and work W done by the environment are given by:

The number of degrees of freedom of a triatomic molecule is:

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The diagram shows three isotherms for an ideal gas, with T₃-T₂the same as T₂-T₁.It also shows five thermodynamic processes carried out on the gas.Rank the processes in order of the change in the internal energy of the gas, least to greatest.

The temperature of n moles of an ideal monatomic gas is increased by $\Delta$ T at constant pressure.The energy Q absorbed as heat, change $\Delta$ E_int in internal energy, and work W done by the environment are given by:

How many molecules are in a sample of 10^-³ mol?

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

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:

For a gas at thermal equilibrium the average speed v, the most probable speed v_p, and the root-mean-square speed v_rms are in the order:

Use R = 8.2* 10^-5 m³ .atm/mol . K and N_A = 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:

The temperature of n moles of an ideal monatomic gas is increased by $\Delta$ T at constant volume.The energy Q absorbed as heat, change $\Delta$ E_int in internal energy, and work W done by the environment are given by: