Thermodynamics

James Joule did much to establish the value of the

• universal gravitational constant

• specific heat capacity of helium

• charge of an electron

• mechanical equivalent of heat

• speed of light

If the average kinetic energy of the molecules in an ideal gas at a temperature of 300 K is E, the average kinetic energy at a temperature of 600 K is

• 4E

• $\sqrt{2}\ E$

• $\frac{E}{\sqrt{2}}$

• E

• 2E

Which of the following statements is NOT a correct assumption of the classical model of an ideal gas?

• The volume of the molecules is negligible compared with the volume occupied by the gas.

• The collisions between molecules are inelastic.

• The molecules obey Newton's laws of motion.

• The molecules are in random motion.

• The only appreciable forces on the molecules are those that occur during collisions.

Which of the following will occur if the average speed of the gas molecules in a closed rigid container is increased?

• The pressure of the gas will increase.

• The density of the gas will increase.

• The density of the gas will decrease.

• The pressure of the gas will decrease.

• The temperature of the gas will decrease.

For the process X→Y, ΔU is greater than zero and

• Q<0 and W = 0

• Q<0 and W>0

• Q>0 and W<0

• Q>0 and W>0

• Q>0 and W=0

For the process Y→Z, Q is greater than zero and

• W=0 and $\Delta$ U<0

• W=0 and $\Delta$ U>0

• W>0 and $\Delta$ U>0

• W >0 and $\Delta$ U=0

• W<0 and $\Delta$ U=0

An ideal gas confined in a box initially has pressure P. If the absolute temperature of the gas is doubled and the volume of the box is quadrupled, the pressure is

• P/4

• P/2

• P/8

• 2P

• P

Which of the following is always a characteristic of an adiabatic process?

• No heat flows into or out of the system (Q = 0).

• The temperature does not change (ΔT = 0).

• No work is done on or by the system (W = 0).

• The internal energy does not change (ΔU = 0).

• The pressure does not change (ΔP = 0).

A certain quantity of an ideal gas initially at temperature T₀, pressure p₀, and volume V₀ is compressed to one-half its initial volume. As shown above, the process may be adiabatic (process 1), isothermal (process 2), or isobaric (process 3).

Which of the following is true of the mechanical work done on the gas?

• It is greatest for process 1.

• It is the same for processes I and 2 and less for process 3.

• It is the same for all three processes.

• It is the same for processes 2 and 3 and less for process 1.

• It is greatest for process 3.

A certain quantity of an ideal gas initially at temperature T₀, pressure p₀, and volume V₀ is compressed to one-half its initial volume. As shown above, the process may be adiabatic (process 1), isothermal (process 2), or isobaric (process 3).

Which of the following is true of the final temperature of this gas?

• It is greatest for process 3.

• It is the same for processes 1 and 2.

• It is greatest for process 2.

• It is the same for processes 1 and 3.

• It is greatest for process 1