S15--AP Phys Q4--Heat-Thermo Ch13_14_15 PRACTICE

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1 Name: Class: Date: S5--AP Phys Q4--Heat-Thermo Ch3_4_5 PRACTICE Multiple Choice Identify the choice that best completes the statement or answers the question.. Which of the following is a thermodynamic process in which a system returns to the same conditions under which it started? a. a cyclic process b. an isothermal process c. an isovolumetric process d. an adiabatic process 2. According to the first law of thermodynamics, the difference between energy transferred to or from a system as heat and energy transferred to or from a system by work is equivalent to which of the following? a. volume change b. pressure change c. entropy change d. internal energy change 3. Which of the following is not a widely used temperature scale? a. Kelvin b. Celsius c. Joule d. Fahrenheit 4. An ideal gas system undergoes an adiabatic process in which it expands and does 20 J of work on its environment. How much energy is transferred to the system as heat? a. 20 J b. 5 J c. 0 J d. 20 J 5. Which of the following best describes the relationship between two systems in thermal equilibrium? a. The velocity is zero. b. The volumes are equal. c. No net energy is exchanged. d. The masses are equal. 6. Which of the following is a direct cause of a substance s temperature increase? a. Energy is removed from the particles of the substance. b. The volume of the substance decreases. c. Kinetic energy is added to the particles of the substance. d. The number of atoms and molecules in a substance changes. 7. Energy is transferred as heat between two objects, one with a temperature of 5 C and the other with a temperature of 20 C. If two other objects are to have the same amount of energy transferred between them, what might their temperatures be? a. 80 C and 90 C b. 7 C and 32 C c. 0 C and 5 C d. 5 C and 25 C 8. An ideal gas system is maintained at a constant volume of 4 L. If the pressure is constant, how much work is done by the system? a. 8 J b. 0 J c. 30 J d. 5 J 9. To which of the following is high temperature related? a. high particle kinetic energy b. large volume c. low particle kinetic energy d. zero net energy transfer 0. Which of the following describes a substance in which the temperature and pressure remain constant while the substance experiences an inward transfer of energy? a. gas b. substance undergoing a change of state c. liquid d. solid. What occurs when a system s disorder is increased? a. More energy is available to do work. b. No work is done. c. No energy is available to do work. d. Less energy is available to do work. 2. During an isovolumetric process, which of the following does not change? a. internal energy b. volume c. pressure d. temperature 3. Which of the following terms describes a transfer of energy? a. kinetic energy b. internal energy c. temperature d. heat 4. How is energy transferred as heat always directed? a. from an object with higher mass to an object of lower mass b. from an object at low temperature to an object at high temperature c. from an object at high temperature to an object at low temperature d. from an object at low kinetic energy to an object at high kinetic energy 5. A substance registers a temperature change from 20 C to 40 C. To what incremental temperature change does this correspond? a. 40 K b. 36 K c. 33 K d. 20 K

2 Name: 6. Energy transfer as heat between two objects depends on which of the following? a. The difference in volume of the two objects. b. The difference in temperature of the two objects. c. The difference in composition of the two objects. d. The difference in mass of the two objects. 7. What accounts for an increase in the temperature of a gas that is kept at constant volume? a. Energy has been added as work done on the gas. b. Energy has been removed as heat from the gas. c. Energy has been added as heat to the gas. d. Energy has been removed as work done by the gas. 8. A thermodynamic process occurs, and the entropy of a system decreases. What can be concluded about the entropy change of the environment? a. It increases. b. It stays the same. c. It could increase or decrease, depending on the process. d. It decreases. 9. An ideal gas system undergoes an isovolumetric process in which 20 J of energy is added as heat to the gas. What is the change in the system s internal energy? a. 20 J b. 5 J c. 0 J d. 20 J 20. According to the second law of thermodynamics, which of the following statements about a heat engine operating in a complete cycle must be true? a. Heat from a high-temperature reservoir must be completely converted to internal energy. b. Heat from a high-temperature reservoir cannot be completely converted to work. c. Heat from a high-temperature reservoir equals the entropy increase. d. Heat from a high-temperature reservoir must be completely converted to work. 2. When a drop of ink mixes with water, what happens to the entropy of the system? a. The system s entropy decreases, and the total entropy of the universe increases. b. The system s entropy increases, and the total entropy of the universe increases. c. The system s entropy increases, and the total entropy of the universe decreases. d. The system s entropy decreases, and the total entropy of the universe decreases. 22. The use of fiberglass insulation in the outer walls of a building is intended to minimize heat transfer through what process? a. radiation b. convection c. vaporization d. conduction 23. Energy transferred as heat occurs between two bodies in thermal contact when they differ in which of the following properties? a. mass b. specific heat c. temperature d. density 24. What happens to the internal energy of an ideal gas when it is heated from 0 C to 4 C? a. It decreases. b. It remains constant. c. It is impossible to determine. d. It increases. 25. Which of the following is a set of particles or interacting components to which energy is added or from which energy is removed? a. a system b. an environment c. an engine d. an ideal gas 26. If two small beakers of water, one at 70 C and one at 80 C, are emptied into a large beaker, what is the final temperature of the water? a. The final temperature is between 70 C and 80 C. b. The final temperature is greater than 80 C. c. The final temperature is less than 70 C. d. The water temperature will fluctuate. 27. Which of the following is true during a phase change? a. Temperature decreases. b. Temperature remains constant. c. There is no transfer of energy as heat. d. Temperature increases. 28. A chunk of ice with a mass of kg at 0 C melts and absorbs J of heat in the process. Which best describes what happened to this system? a. Its entropy decreased. b. Work was converted to energy. c. Its entropy remained constant. d. Its entropy increased. 29. The zeroth law of thermodynamics pertains to what relational condition that may exist between two systems? a. zero net forces b. zero velocities c. zero temperature d. thermal equilibrium e. none of the above 30. A substance is heated from 5 C to 35 C. What would the same incremental change be when registered in kelvins? a. 20 b. 40 c. 36 d. 33 e. 42 2

3 Name: 3. An ideal gas is confined to a container with constant volume. The number of moles is constant. By what factor will the pressure change if the absolute temperature triples? a. /9 b. /3 c. 3.0 d. 9.0 e An ideal gas is confined to a container with adjustable volume. The number of moles and temperature are constant. By what factor will the volume change if pressure triples? a. /9 b. /3 c. 3.0 d. 9.0 e Two moles of nitrogen gas are contained in an enclosed cylinder with a movable piston. If the gas temperature is 298 K, and the pressure is N/m 2, what is the volume? (R = 8.3 J/mol K) a m 3 b m 3 c m 3 d m 3 e m One way to heat a gas is to compress it. A gas at.00 atm at 25.0 C is compressed to one tenth of its original volume, and it reaches 40.0 atm pressure. What is its new temperature? a. 500 K b. 500 C c. 92 C d. 99 C e. 92 K 35. A helium-filled weather balloon has a 0.90 m radius at liftoff where air pressure is.0 atm and the temperature is 298 K. When airborne, the temperature is 20 K, and its radius expands to 3.0 m. What is the pressure at the airborne location? a atm b atm c atm d atm e. 0.5 atm 36. The mass of a hot-air balloon and its cargo (not including the air inside) is 200 kg. The air outside is at a temperature of 0 C and a pressure of atm = 0 5 N/m 2. The volume of the balloon is 400 m 3. Which temperature below of the air in the balloon will allow the balloon to just lift off? (Air density at 0 C is.25 kg/m 3.) a. 37 C b. 69 C c. 99 C d. 200 C e. 220 C 37. A spherical air bubble originating from a scuba diver at a depth of 8.0 m has a diameter of.0 cm. What will the bubble's diameter be when it reaches the surface? (Assume constant temperature.) a. 0.7 cm b..0 cm c..4 cm d..7 cm e. 2.3 cm 38. Heat flow occurs between two bodies in thermal contact when they differ in what property? a. mass b. specific heat c. density d. temperature e. volume 39. A 0-kg piece of aluminum (which has a specific heat of 900 J/kg C) is warmed so that its temperature increases by 5.0 C. How much heat was transferred into it? a J b J c J d J e J 40. A 0.2-kg aluminum plate, initially at 20 C, slides down a 5-m-long surface, inclined at a 30 angle to the horizontal. The force of kinetic friction exactly balances the component of gravity down the plane so that the plate, once started, glides down at constant velocity. If 90% of the mechanical energy of the system is absorbed by the aluminum, what is its temperature increase at the bottom of the incline? (Specific heat for aluminum is 900 J/kg C.) a. 0.6 C b C c C d C e. 0.0 C g of dry ice (solid CO 2 ) is dropped into a beaker containing 500 g of 66 C water. The dry ice converts directly to gas, leaving the solution. When the dry ice is gone, the final temperature of the water is 29 C. What is the heat of vaporization of solid CO 2? (c water =.00 cal/g C) a. 37 cal/g b. 74 cal/g c. cal/g d. 48 cal/g e. 65 cal/g 42. If one's hands are being warmed by holding them to one side of a flame, the predominant form of heat transfer is what process? a. conduction b. radiation c. convection d. vaporization e. none of the above 43. The use of fiberglass insulation in the outer walls of a building is intended to minimize heat transfer through the wall by what process? a. conduction b. radiation c. convection d. vaporization e. none of the above 44. How does the heat energy from the sun reach us through the vacuum of space? a. conduction b. radiation c. convection d. none of the above choices are valid e. both choices B and C are valid 45. According to the first law of thermodynamics, the sum of the heat gained by a system and the work done on that same system is equivalent to which of the following? a. entropy change b. internal energy change c. temperature change d. specific heat e. both choices A and B are valid. 3

4 Name: 46. In an isovolumetric process by an ideal gas, the system's heat gain is equivalent to a change in: a. temperature. b. volume. c. pressure. d. internal energy. e. none of the above. 47. A closed 2.0-L container holds 3.0 mol of an ideal gas. If 200 J of heat is added, what is the change in internal energy of the system? a. zero b. 00 J c. 50 J d. 200 J e. 250 J 48. An adiabatic expansion refers to the fact that: a. no heat is transferred between a system and its surroundings. b. the pressure remains constant. c. the temperature remains constant. d. the volume remains constant. e. both choices A and B are valid. 49. A turbine takes in 000-K steam and exhausts the steam at a temperature of 500 K. What is the maximum theoretical efficiency of this system? a. 24% b. 33% c. 50% d. 67% e. 73% 50. During each cycle of operation a refrigerator absorbs 55 cal from the freezer compartment and expels 85 cal to the room. If one cycle occurs every 0 s, how many minutes will it take to freeze 500 g of water, initially at 0 C? (L v = 80 cal/g) a. 800 min b min c. 20 min d. 60 min e. 30 min Problem 5. Liquid oxygen has a temperature of 83 C. What is this temperature in kelvins? 52. The internal energy of a system is initially 63 J. A total of 7 J of energy is added to the system as heat while the system does 59 J of work. What is the system s final internal energy? 53. An engine with a mass of 325 kg and an initial temperature of 22.0 C takes in J of energy as heat and does J of work. If the rest of the energy is retained by the engine, which has a specific heat capacity of 550 J/kg C, what is the engine s final temperature? 54. Over several cycles, a refrigerator compressor does work on the refrigerant by causing a net change in volume of 0.62 m 3 under a constant pressure of Pa. This causes the refrigerant to remove J of energy as heat from the interior of the refrigerator. Because the compartment is not perfectly insulated, J of energy leaks into the compartment from outside the refrigerator. Treating the compressor, refrigerant, and refrigerator compartment as a single system, and assuming that the refrigerator requires 3 J of energy to change its interior temperature by.00 C, what is the final temperature of the refrigerator? Assume that its temperature at the start of the process is 25.7 C. 55. The piston of an engine has a radius of m and is displaced a distance of 0.23 m when the pressure within the cylinder is Pa. If the efficiency of the engine is 0.28, how much work must the engine give up as heat to the low-temperature reservoir? 4

5 S5--AP Phys Q4--Heat-Thermo Ch3_4_5 PRACTICE Answer Section MULTIPLE CHOICE. ANS: A PTS: DIF: I OBJ: ANS: D PTS: DIF: I OBJ: ANS: C PTS: DIF: I OBJ: ANS: C PTS: DIF: II OBJ: ANS: C PTS: DIF: I OBJ: ANS: C PTS: DIF: I OBJ: ANS: B PTS: DIF: II OBJ: ANS: B PTS: DIF: II OBJ: ANS: A PTS: DIF: I OBJ: ANS: B PTS: DIF: I OBJ: ANS: D PTS: DIF: I OBJ: ANS: B PTS: DIF: I OBJ: ANS: D PTS: DIF: I OBJ: ANS: C PTS: DIF: I OBJ: ANS: D PTS: DIF: II OBJ: ANS: B PTS: DIF: I OBJ: ANS: C PTS: DIF: I OBJ: ANS: A PTS: DIF: II OBJ: ANS: D PTS: DIF: II OBJ: ANS: B PTS: DIF: I OBJ: ANS: B PTS: DIF: II OBJ: ANS: D PTS: DIF: I OBJ: ANS: C PTS: DIF: I OBJ: ANS: D PTS: DIF: I OBJ: ANS: A PTS: DIF: I OBJ: ANS: A PTS: DIF: I OBJ: ANS: B PTS: DIF: I OBJ: ANS: D PTS: DIF: I OBJ: ANS: D PTS: DIF: TOP: 0. Temperature and the Zeroth Law of Thermodynamics 0.2 Thermometers and Temperature Scales 30. ANS: A PTS: DIF: TOP: 0. Temperature and the Zeroth Law of Thermodynamics 0.2 Thermometers and Temperature Scales 3. ANS: C PTS: DIF: TOP: 0.4 Macroscopic Description of an Ideal Gas 32. ANS: B PTS: DIF: TOP: 0.4 Macroscopic Description of an Ideal Gas 33. ANS: B PTS: DIF: 2 TOP: 0.4 Macroscopic Description of an Ideal Gas 34. ANS: D PTS: DIF: 3 TOP: 0.4 Macroscopic Description of an Ideal Gas 35. ANS: C PTS: DIF: 2 TOP: 0.4 Macroscopic Description of an Ideal Gas 36. ANS: D PTS: DIF: 3 TOP: 0.4 Macroscopic Description of an Ideal Gas

6 37. ANS: C PTS: DIF: 3 TOP: 0.4 Macroscopic Description of an Ideal Gas 38. ANS: D PTS: DIF: TOP:. Heat and Internal Energy.2 Specific Heat 39. ANS: A PTS: DIF: 2 TOP:. Heat and Internal Energy.2 Specific Heat 40. ANS: B PTS: DIF: 3 TOP:. Heat and Internal Energy.2 Specific Heat 4. ANS: D PTS: DIF: 2 TOP:.4 Latent Heat and Phase Change 42. ANS: B PTS: DIF: TOP:.5 Energy Transfer 43. ANS: A PTS: DIF: TOP:.5 Energy Transfer 44. ANS: B PTS: DIF: TOP:.5 Energy Transfer 45. ANS: B PTS: DIF: TOP: 2.2 The First Law of Thermodynamics 46. ANS: D PTS: DIF: 2 TOP: 2.2 The First Law of Thermodynamics 47. ANS: D PTS: DIF: TOP: 2.2 The First Law of Thermodynamics 48. ANS: A PTS: DIF: TOP: 2.2 The First Law of Thermodynamics 49. ANS: C PTS: DIF: 2 TOP: 2.3 Heat Engines and the Second Law of Thermodynamics 50. ANS: C PTS: DIF: 3 TOP: 2.3 Heat Engines and the Second Law of Thermodynamics PROBLEM 5. ANS: K T C = 83 C T = T C T = ( ) K = K PTS: DIF: IIIA OBJ: ANS: 75 J U i = 63 J Q = 7 J W = 59 J Work is done by the system, so W is positive. Energy is added as heat to the system, so Q is positive. U = U f U i = Q W U f = U i + Q W = 63 J + 7 J 59 J = 75 J PTS: DIF: IIIA OBJ:

7 53. ANS: 25.9 C m = 325 kg T i = 22.0 C Q = J W = J c p = 550 J/kg C Work is done by the system, so W is positive. Energy is added as heat to the system, so Q is positive. U = Q W U = mc p T = mc p (T f T i ) mc p (T f T i ) = Q W T f = Q W mc p + T i T f T f = J J (325 kg)(550 J/kg C) = 3.9 C C = 25.9 C C = J (325 kg)(550 J/kg C) C PTS: DIF: IIIB OBJ:

8 54. ANS: 2.9 C V = 0.62 m 3 P = Pa Q removed = J Q added = J U/ T = 3 J/.00 C T initial = 25.7 C U = Q W W = P V Q = Q removed + Q added U = Q removed + Q added P V U = J J ( Pa)( 0.62 m 3 ) U = J J J = J T = T final T initial = Ê Á U 3 J.00 C T final = Ê Á U 3 J.00 C + T initial = J Ê 3 J C = 22.8 C C = 2.9 C Á.00 C PTS: DIF: IIIC OBJ:

9 55. ANS: J r = m d = 0.23 m P = Pa eff = 0.28 W net = P V = PAd A = πr 2 eff = W net Q h W net = Q h Q c Q c = Q h W net = W Ê net W eff net = W net Á eff = PAd Ê Á eff Q c = ( Pa)(π)( m) 2 Ê (0.23 m) Á 0.28 Q c = ( Pa)(π)( m) 2 (0.23 m) ( 3.6 ) = Ê Pπr2 d Á eff Q c = ( Pa)(π)( m) 2 (0.23 m) ( 2.6) = J PTS: DIF: IIIC OBJ:

Chapter 10, Thermal Physics

Chapter 10, Thermal Physics CHAPTER 10 1. If it is given that 546 K equals 273 C, then it follows that 400 K equals: a. 127 C b. 150 C c. 473 C d. 1 200 C 2. A steel wire, 150 m long at 10 C, has a coefficient of linear expansion