MULTIPLE CHOICE. Choose the one alternative that best ...

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1) When a gas undergoes an isothermal process, there is

1)

A) no change in the volume of the gas.

B) no change in the pressure of the gas.

C) no heat added to the gas.

D) no work done by (or on) the gas.

E) no change in the temperature of the gas.

2) The process shown in the pV diagram in the figure is an

2)

A) isochoric expansion. B) isothermal expansion. C) adiabatic expansion. D) isobaric expansion. E) isochoric compression.

3) When a fixed amount of ideal gas goes through an adiabatic expansion,

3)

A) its internal (thermal) energy does not change.

B) the gas does no work.

C) no heat enters or leaves the gas.

D) its temperature cannot change.

E) its pressure must increase.

4) An engine manufacturer makes the claim that the engine they have developed will, on each cycle, take 4) 100 J of heat out of boiling water at 100?C, do mechanical work of 80 J, and exhaust 20 J of heat at 10?C. What, if anything, is wrong with this claim? A) There is nothing wrong with this claim because 100 J = 20 J + 80 J. B) An engine would operate by taking in heat at the lower temperature and exhausting heat at the higher temperature. C) The efficiency of this engine is greater than the ideal Carnot cycle efficiency. D) This engine violates the first law of thermodynamics because 100 J + 20 J 80 J. E) The heat exhausted must always be greater than the work done according to the second law of thermodynamics.

1

5) A hot piece of iron is thrown into the ocean and its temperature eventually stabilizes. Which of the

5)

following statements concerning this process is correct? (There may be more than one correct choice.)

A) The ocean gains more entropy than the iron loses.

B) The entropy gained by the iron is equal to the entropy lost by the ocean.

C) The ocean gains less entropy than the iron loses.

D) The entropy lost by the iron is equal to the entropy gained by the ocean.

E) The change in the entropy of the iron-ocean system is zero.

6) When a gas expands adiabatically,

6)

A) the internal (thermal) energy of the gas increases.

B) the internal (thermal) energy of the gas decreases.

C) it does no work.

D) the temperature of the gas remains constant.

E) work is done on the gas.

7) A gas is taken through the cycle shown in the pV diagram in the figure. During one cycle, how much

7)

work is done by the gas?

A) p0V0

B) 4 p0V0

C) 2 p0V0

D) 3 p0V0

8) Two processes are shown on the pV diagram in the figure. One of them is an adiabat and the other one is 8) an isotherm. Which process is the isotherm?

A) process A B) process B C) The processes shown are neither isotherms nor adiabats. D) It is not possible to tell without knowing if the gas is monatomic or diatomic.

9) A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the

9)

change in the internal (thermal) energy of the gas?

A) 400 J

B) 0 J

C) 800 J

D) -800 J

E) More information is needed to answer this question.

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10) A Carnot cycle consists of

10)

A) two adiabats and two isobars.

B) four adiabats.

C) two adiabats and two isotherms.

D) two isobars and two isotherms.

E) four isotherms.

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

11) Consider two cylinders of gas identical in all respects except that one contains oxygen O 2 and 11) the other helium He. Both cylinders initially contain the same volume of gas at 0?C and 1 atm of pressure and are closed by a movable piston at one end. Both gases are now compressed adiabatically to one-third their original volume. (a) Which gas will show the greater temperature increase? A) the O2 B) the He C) Neither; both will show the same increase. D) It is impossible to tell from the information given. (b) Which gas will show the greater pressure increase? A) the O2 B) the He C) Neither; both will show the same increase. D) It is impossible to tell from the information given.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

12) The figure (not to scale) shows a pV diagram for 1.8 g of helium gas (He) that undergoes the process

12)

1 2 3. Find the value of V3. The ideal gas constant is R = 8.314 J/mol ? K = 0.0821 L ? atm/mol ? K,

and the atomic weight of helium is 4.0 g/mol.

A) 17 L

B) 8.6 L

C) 34 L

D) 69 L

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13) The figure shows a pV diagram for 8.3 g of nitrogen gas (N2) in a sealed container. The temperature T1 13) of the gas in state 1 is 79?C. What are (a) the pressure p1 of the gas in state 1 and (b) the temperature T2 of the gas in state 2? The ideal gas constant is R = 8.314 J/mol ? K = 0.0821 L ? atm/mol ? K, and the ATOMIC weight of nitrogen is 14 g/mol.

A) (a) 86 atm, (b) 160?C. C) (a) 19 atm, (b) 160?C.

B) (a) 86 atm, (b) 700?C. D) (a) 19 atm, (b) 700?C.

14) How much work is done by 3.00 mol of ideal gas when it triples its volume at a constant temperature

14)

of 127?C? The ideal gas constant is R = 8.314 J/mol ? K.

A) 12.7 kJ

B) 1.20 kJ

C) 9.97 kJ

D) 11.0 kJ

E) 15.3 kJ

15) An ideal gas in a balloon is kept in thermal equilibrium with its constant-temperature surroundings.

15)

How much work is done by the gas if the outside pressure is slowly reduced, allowing the balloon to

expand to 6.0 times its original size? The balloon initially has a pressure of 645.0 Pa and a volume of

0.10 m3. The ideal gas constant is R = 8.314 J/mol ? K.

A) 120 J

B) -330 J

C) 390 J

D) 6.0 J

16) An ideal monatomic gas cools from 455.0 K to 405.0 K at constant volume as 831 J of energy is

16)

removed from it. How many moles of gas are in the sample? The ideal gas constant is

R = 8.314 J/mol ? K.

A) 1.33 mol

B) 1.50 mol

C) 0.725

D) 2.50 mol

E) 2.15 mol

mol

17) A monatomic ideal gas undergoes an isothermal expansion at 300 K, as the volume increased from

17)

0.03 m3 to 0.21 m3. The final pressure of the gas is 60 kPa. The ideal gas constant is R = 8.314 J/mol ? K.

The change in the internal (thermal) energy of the gas is closest to

A) 0.00 kJ.

B) 25 kJ.

C) 12 kJ.

D) -25 kJ.

E) -12 kJ.

4

18) An expansion process on an ideal diatomic gas has a linear path between the initial and final states on a 18)

pV diagram. The initial pressure is 300 kPa, the initial volume is 0.020 m3, and the initial temperature

is 390 K. The final pressure is 160 kPa and the final temperature is 310 K. The change in the internal

(thermal) energy of the gas is closest to

A) 3100 J.

B) -1800 J.

C) -3100 J.

D) 1800 J.

E) 0.00 J.

19) An ideal gas with = 1.67 is initially at 0?C in a volume of 10.0 L at a pressure of 1.00 atm. It is then

19)

expanded adiabatically to a volume of 10.4 L. What is the final temperature of the gas?

A) -20?C

B) -7.1?C

C) 2.5?C

D) -23?C

E) 68?C

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

20) The pV diagram shown is for 7.50 moles of an ideal diatomic gas taken through a cycle from a 20) to b to c. The ideal gas constant is R = 8.314 J/mol ? K.

(a) What is the highest temperature reached by the gas during the cycle? (b) What net work does the gas do during the cycle? (c) How much heat is exchanged with the gas during part bc of the cycle? Does it enter or leave the gas? (d) What is the change in the internal (thermal) energy of the gas during part bc of the cycle? (e) What is the change in the internal (thermal) energy of the gas during the entire cycle?

21) A fixed amount of ideal gas goes through a process abc. In state a, the temperature of the gas is 21) 152?C, its pressure is 1.25 atm, and it occupies a volume of 0.250 m 3. It then undergoes an isothermal expansion to state b that doubles its volume, followed by an isobaric compression back to its original volume at state c. (Hint: First show this process on a pV diagram.) The ideal gas constant is 8.314 J/mol ? K, and 1.00 atm = 1.01 ? 105 Pa. (a) How many moles does this gas contain? (b) What is the change in the internal energy of the gas between states a and b? (c) What is the net work done on (or by) this gas during the entire process? (d) What is the temperature of the gas in state c?

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