CH. 19 PRACTICE

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

1) When a fixed amount of ideal gas goes through an isobaric expansion,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 must increase.E) its pressure must increase.

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2) A container of ideal gas has a movable frictionless piston. This container is placed in avery large water bath and slowly compressed so that the temperature of the gas remainsconstant and equal to the temperature of the water. Which of the following statementsabout this gas are true for this process? (There may be more than one correct choice.)A) Heat leaves the gas during the compression.B) Since the gas and water are at the same temperature, no heat can flow between

them, which makes this an adiabatic compression.C) The internal energy of the gas increases during the compression because work is

done on the gas.D) The internal (thermal) energy of the gas does not change during the compression.E) Since the temperature of the gas remains constant, the pressure of the gas must

also remain constant.

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3) An ideal gas is compressed in a well-insulated chamber using a well-insulated piston.This process isA) isobaric. B) isothermal. C) isochoric. D) adiabatic.

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

4) Consider two cylinders of gas identical in all respects except that one containsoxygen O2 and the other helium He. Both cylinders initially contain the samevolume of gas at 0°C and 1 atm of pressure and are closed by a movable pistonat one end. Both gases are now compressed adiabatically to one-third theiroriginal volume.(a) Which gas will show the greater temperature increase?

A) the O2B) the HeC) 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 O2B) the HeC) Neither; both will show the same increase.D) It is impossible to tell from the information given.

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

1) The entropy of an isolated system must be conserved, so it never changes.A) True B) False

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2) As a result of any natural process, the total entropy of any system plus that of itsenvironmentA) always stays the same. B) sometimes decreases.C) never decreases. D) never increases.

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3) An ice cube at 0°C is placed in a very large bathtub filled with water at 30°C andallowed to melt, causing no appreciable change in the temperature of the bath water.Which one of the following statements is true?A) The net entropy change of the system (ice plus water) is zero because no heat was

added to the system.B) The entropy lost by the ice cube is equal to the entropy gained by the water.C) The entropy of the water does not change because its temperature did not change.D) The entropy of the system (ice plus water) increases because the process is

irreversible.E) The entropy gained by the ice cube is equal to the entropy lost by the water.

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4) What is the change in entropy of 10.0 moles of ideal monatomic gas that reversiblyundergoes the isothermal expansion shown in the figure? The ideal gas constant isR = 8.314 J/(mol • K).

A) 45.2J/K

B) 63.1J/K

C) 90.8J/K

D) 221J/K

E) 104J/K

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5) A hot piece of iron is thrown into the ocean and its temperature eventually stabilizes.Which of the following statements concerning this process is correct? (There may bemore than one correct choice.)A) The entropy lost by the iron is equal to the entropy gained by the ocean.B) The ocean gains less entropy than the iron loses.C) The change in the entropy of the iron-ocean system is zero.D) The ocean gains more entropy than the iron loses.E) The entropy gained by the iron is equal to the entropy lost by the ocean.

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6) A brass rod, 75.0 cm long and having a cross-sectional area of 2.50 cm2, conducts heatfrom a large furnace at 375°C into a very large cold water bath at 10.0°C without losingany heat at the lateral surface of the rod. Steady state has been established, and thethermal conductivity of brass is 109 W/m • K. The rate at which the entropy of thesystem (furnace plus water) is changing is closest toA) 6.74 × 10-2 W/K.B) 2.64 × 10-2 W/K.C) 3.54 × 10-2 W/K.D) 2.05 × 10-2 W/K.E) 4.69 × 10-2 W/K.

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