Physics Test 4

3) As shown in the figure, a bimetallic strip, consisting of metal G on the top and metal H on the bottom, is rigidly attached to a wall at the left. The coefficient of linear thermal expansion for metal G is greater than that of metal H. If the strip is uniformly heated, it will A) curve upward. B) curve downward. C) remain horizontal, but get longer. D) remain horizontal, but get shorter. E) bend in the middle.

: B

41) If 50 g of lead (of specific heat 0.11 kcal/kg ∙ C°) at 100°C is put into 75 g of water (of specific heat 1.0 kcal/kg ∙ C°) at 0°C. What is the final temperature of the mixture? A) 2.0°C B) 6.8°C C) 25°C D) 50°C

: B

46) Your lungs hold 4.2 L of air at a temperature of 27°C and a pressure of 101.3 kPa. How many moles of air do your lungs hold? (R = 8.31 J/mol ∙ K) A) 0.15 moles B) 0.17 moles C) 0.19 moles D) 0.21 moles E) 0.23 moles

: B

63) The "hot shot" heat engine operating between 40°C and 380°C has an efficiency that is 60% of that of an ideal Carnot engine operating between the same temperatures. If the "hot shot" engine absorbs heat at a rate of 60 kW, at what rate does it exhaust heat? A) 36 kW B) 41 kW C) 57 kW D) 60 kW

: B

66) A sealed container holds 0.020 moles of ideal nitrogen (N2) gas, at a pressure of 1.5 atm and a temperature of 290 K. The atomic mass of nitrogen is 14.0 g/mol. What is the average translational kinetic energy of a nitrogen molecule? The Boltzmann constant is 1.38 × 10-23 J/K. A) 4.0 ×1021 J B) 6.0 ×1021 J C) 8.0 ×1021 J D) 10 ×1021 J E) 12 ×1021 J

: B

69) Suppose that the Department of Energy develops a new reversible engine that has a coefficient of performance (COP) of 4.0 when operated as a refrigerator and a COP of 5.0 when operated as a heat pump. What is its thermal efficiency when operated as a heat engine doing work? A) 10% B) 20% C) 25% D) 45% E) 80%

: B

69) The molecular weight of nitrogen, N2, is 28 g/mol. What is the rms speed of nitrogen molecules in a cooler at 8.0°C? The Boltzmann constant is 1.38 × 10-23 J/K and NA = 6.022 × 1023 molecules/mol. A) 450 m/s B) 500 m/s C) 550 m/s D) 600 m/s E) 650 m/s

: B

7) A machine part consists of 0.10 kg of iron (of specific heat 470 J/kg ∙ K ) and 0.16 kg of copper (of specific heat 390 J/kg ∙ K). How much heat must be added to the gear to raise its temperature from 18°C to 53°C? A) 910 J B) 3800 J C) 4000 J D) 4400 J

: B

85) What is the net power that a person with surface area of 1.20 m2 radiates if his emissivity is 0.895, his skin temperature is 27°C, and he is in a room that is at a temperature of 17°C? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 60.3 W B) 62.6 W C) 65.7 W D) 68.4 W E) 64.8 W

: B

89) Two identical objects are placed in a room with a temperature of 20°C. Object A has a temperature of 50°C, while object B has a temperature of 90°C. What is the ratio of the net power emitted by object B to the power emitted by object A? A) 1.7 B) 2.8 C) 81 D) 17 E) 21

: B

9) The weather outside is frightful. The temperature is -22°F. What is the corresponding temperature in the Celsius scale? A) -35°C B) -30°C C) -22°C D) -20°C E) -12°C

: B

93) A container of ideal gas at STP undergoes an isothermal expansion and its entropy changes by 3.7 J/K. How much work does it do? A) 0.0 J B) 1.0 × 103 J C) -1.0 × 103 J D) 1.4 × 103 J E) -1.4 × 103 J

: B

16) By what primary heat transfer mechanism does the sun warm the earth? A) convection B) conduction C) radiation D) All of the above processes are equally important in combination.

: C

17) During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the work done by the gas in the process? A) 0 J B) 5.0 J C) -5.0 J D) -10 J

: C

48) A weather balloon containing 2.0 m3 of hydrogen gas rises from a location at which the temperature is 22°C and the pressure is 101 kPa to a location where the temperature is -39°C and the pressure is 20 kPa. If the balloon is free to expand so that the pressure of the gas inside is equal to the ambient pressure, what is the new volume of the balloon? A) 4.0 m3 B) 6.0 m3 C) 8.0 m3 D) 10 m3 E) 12 m3

: C

50) A heat engine having the maximum possible efficiency has an efficiency of 25% when operating between two heat reservoirs. If the temperature of the cold reservoir is 300 K, what is the temperature of the hot reservoir? A) 350 K B) 375 K C) 400 K D) 450 K E) 500 K

: C

51) When 50 g of a certain material at 100°C is mixed with 100 g of water at 0°C, the final temperature is 40°C. What is the specific heat of the material? The specific heat of water is 1.00 kcal/kg ∙ C°. A) 0.33 kcal/kg ∙ C° B) 0.75 kcal/kg ∙ C° C) 1.3 kcal/kg ∙ C° D) 7.5 kcal/kg ∙ C°

: C

56) Two ideal Carnot heat engines have the same efficiency. One operates between 5.0 × 102 K and 3.0 × 102 K, and the other between 4.0 × 102 K and some lower temperature. What is the lower temperature? A) 200 K B) 220 K C) 240 K D) 260 K E) 280 K

: C

6) If 150 kcal of heat raises the temperature of 2.0 kg of a material by 400 F°, what is the specific heat capacity of the material? A) 1.35 kcal/kg ∙ C° B) 0.75 kcal/kg ∙ C° C) 0.34 kcal/kg ∙ C° D) 0.19 kcal/kg ∙ C°

: C

70) At what temperature is the rms speed of hydrogen molecules, H2, which have a molecular weight of 2.02 g/mole, equal to 2.0 km/s? The Boltzmann constant is 1.38 × 10-23 J/K and NA = 6.022 × 1023 molecules/mol. A) 17°C B) 34°C C) 51°C D) 68°C E) 72°C

: C

83) How much power does a sphere with a radius of 10 cm radiate into empty space if is has an emissivity of 1.0 and is kept at a temperature of 400 K? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 60 W B) 70 W C) 180 W D) 210 W E) 360 W

: C

86) When 1.0 kg of steam at 100°C condenses to water at 100°C, what is the change in entropy of the steam? The latent heat of vaporization of water is 22.6 × 105 J/kg. A) zero B) 6.1 × 103 J/K C) -6.1 × 103 J/K D) 22.6 × 105 J/K E) -22.6 × 105 J/K

: C

both of them experience the same size gain or loss of heat. D) It is impossible to tell without knowing the masses. E) It is impossible to tell without knowing the volumes.

: C

18) A Carnot cycle consists of A) two adiabats and two isobars. B) two isobars and two isotherms. C) four isotherms. D) two adiabats and two isotherms. E) four adiabats.

: D

11) On a cold day, a piece of metal feels much colder to the touch than a piece of wood. This is due to the difference in which one of the following physical properties of these materials? A) density B) specific heat C) emissivity D) thermal conductivity E) mass

: D

11) The root-mean-square speed of the molecules of an ideal gas is v. The gas is now slowly compressed to one-half its original volume with no change in temperature. What is the root-mean-square speed of the molecules now? A) 4v B) 2v C) v/ D) v E) v/2

: D

12) A steel bridge is 1000 m long at -20°C in winter. What is the change in length when the temperature rises to 40°C in summer? The average coefficient of linear expansion of this steel is 11 × 10-6 K-1. A) 0.33 m B) 0.44 m C) 0.55 m D) 0.66 m

: D

14) An object having a fixed emissivity of 0.725 radiates heat at a rate of 10 W when it is at an absolute temperature T. If its temperature is doubled to 2T, at what rate will it now radiate? A) 20 W B) 40 W C) 80 W D) 160 W E) 320 W

: D

2) The temperature in your classroom is closest to A) 68 K. B) 68°C. C) 50°C. D) 295 K.

: D

22) Suppose that a rigid aluminum wire were to be strung out in a loop that just fits snugly around the equator (assuming a perfectly spherical Earth with a radius of 6.37 × 106 m). If the temperature of the wire is increased by 0.50°C, and the increase in length is distributed equally over the entire length, how far off the ground will the wire loop be if it remained centered on the earth? The coefficient of linear expansion of aluminum is 24 × 10-6 K-1. A) 7.6 mm B) 76 mm C) 76 cm D) 76 m E) 760 m

: D

42) An ideal gas occupies 6.00 × 102 cm3 at 20°C. At what temperature will it occupy 1.20 × 103 cm3 if the pressure is held constant? A) 10°C B) 40°C C) 100°C D) 313°C

: D

45) On a cold day, you take in 4.2 L of air into your lungs at a temperature of 0°C. If you hold your breath until the temperature of the air in your lungs reaches 37°C, what is the volume of the air in your lungs at that point, assuming the pressure does not change? A) 4.2 L B) 4.4 L C) 4.6 L D) 4.8 L E) 5.0 L

: D

58) A 24.0-L tank contains ideal helium gas at 27°C and a pressure of 22.0 atm. How many moles of gas are in the tank? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa) A) 238 mol B) 138 mol C) 17.5 mol D) 21.4 mol E) 76.0 mol

: D

60) A sealed container holds 0.020 moles of ideal nitrogen (N2) gas, at a pressure of 1.5 atm and a temperature of 290 K. The atomic mass of nitrogen is 14.0 g/mol. How many molecules of nitrogen are in the container? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa) A) 1.5 × 1021 mol B) 3.0 × 1021 mol C) 6.0 × 1021 mol D) 1.2 × 1022 mol E) 2.4 × 1022 mol

: D

68) A concrete wall of a cold storage room measures 3.0 m high, 5.0 m wide, and 20 cm thick. The inside wall is to be covered by a layer of wood in order to reduce the rate of heat flow through the wall by 90 percent. The inner surface of the wooden wall is maintained at -10°C and the outer surface of the concrete wall is at 20°C. The thermal conductivities of concrete and wood are 0.80 W/m ∙ K (concrete) and 0.040 W/m ∙ K (wood). What is the temperature difference across the layer of wood? A) 24 C° B) 25 C° C) 26 C° D) 27 C° E) 28 C°

: D

69) A concrete wall of a cold storage room measures 3.0 m high, 5.0 m wide, and 20 cm thick. The inside wall is to be covered by a layer of wood in order to reduce the rate of heat flow through the wall by 90 percent. The inner surface of the wooden wall is maintained at -10°C and the outer surface of the concrete wall is at 20°C. The thermal conductivities of concrete and wood are 0.80 W/m ∙ K (concrete) and 0.040 W/m ∙ K (wood). What should be the thickness of the layer of wood? A) 60 mm B) 70 mm C) 80 mm D) 90 mm E) 100 mm

: D

74) An oxygen molecule, O2, falls in a vacuum. From what height must it fall so that its translational kinetic energy at the bottom of its fall equals the average translational kinetic energy of an oxygen molecule at 920 K? The mass of one O2 molecule is 5.312 × 10-26 kg, and the Boltzmann constant is 1.38 × 10-23 J/K. Neglect air resistance and assume that g remains constant at 9.8 m/s2 throughout the fall of the molecule. A) 49 km B) 12 km C) 24 km D) 37 km E) 5.2 km

: D

78) A window glass that is 0.5 cm thick has dimensions of 3 m by 1.5 m. The thermal conductivity of this glass is 0.8 W/m ∙ K. If the outside surface of the glass is at -10°C and the inside surface is at 20°C, how much heat flows through the window in every hour? A) 50 MJ B) 60 MJ C) 70 MJ D) 80 MJ

: D

both of them experience the same size temperature change. D) It is impossible to tell without knowing the masses. E) It is impossible to tell without knowing the volumes.

: D

21) How much heat must be removed from 456 g of water at 25.0°C to change it into ice at -10.0°C? The specific heat of ice is 2090 J/kg ∙ K, the latent heat of fusion of water is 33.5 × 104 J/kg, and the specific heat of water is 4186 J/kg ∙ K. A) 105 kJ B) 153 kJ C) 57.3 kJ D) 47.7 kJ E) 210 kJ

: E

88) A giant star radiates energy at the rate of 3.0 × 1030 W, and its surface temperature has been measured to be 3000 K. Assuming that it is a perfect emitter, what is the radius of this star?(σ = 5.67 × 10-8 W/m2 ∙ K4) A) 7.8 × 1010 m B) 8.7 × 1010 m C) 1.4 × 1010 m D) 1.9 × 1011 m E) 2.3 × 1011 m

: E

10) A 5.00-g lead BB moving at 44.0 m/s penetrates a wood block and comes to rest inside the block. If half of its kinetic energy is absorbed by the BB, what is the change in the temperature of the BB? The specific heat of lead is 128 J/kg ∙ K. A) 0.940 K B) 1.10 K C) 1.26 K D) 2.78 K E) 3.78 K

: E

27) A metal has a latent heat of fusion of 2.32 × 104 J/kg, a specific heat of 128 J/kg ∙ K, and a melting point of 228°C. A 30-g pellet of this metal at 16°C hits a solid wall and comes to a complete stop. What would the speed of the pellet have to be in order for it to melt completely when it hits the wall, assuming that all of its kinetic energy is transformed into heat within the pellet? A) 207 m/s B) 215 m/s C) 232 m/s D) 273 m/s E) 317 m/s

: E

66) A heat-conducting rod that is wrapped in insulation is constructed with a 0.15-m length of alloy A and a 0.40-m length of alloy B, joined end-to-end. Both pieces have cross-sectional areas of 0.0020 m2. The thermal conductivity of alloy B is known to be 1.8 times as great as that for alloy A. The end of the rod in alloy A is maintained at a temperature of 10°C, and the other end of the rod is maintained at an unknown temperature. When steady state flow has been established, the temperature at the junction of the alloys is measured to be 40° C, and the rate of heat flow in the rod is measured at 56 W. What is the thermal conductivity of alloy A? A) 120 W/m ∙ K B) 125 W/m ∙ K C) 130 W/m ∙ K D) 135 W/m ∙ K E) 140 W/m ∙ K

: E

72) A 400-g stainless steel tea kettle containing 500 g of water is on the stove. The portion of the tea kettle that is in contact with the heating element has an area of 0.090 m2 and is 2.0 mm thick. At a certain moment, the temperature of the water is 75°C, and it is rising at the rate of 3.0 C° per minute. What is the difference in temperature between the inside and the outside of the bottom of the tea kettle? Assume that the inner surface of the kettle is at the same temperature as the water inside. The thermal conductivity of stainless steel is 16.3 W/m ∙ K, the specific heat of the steel is 448 J/kg ∙ K, and the specific heat of water is 4186 J/kg . K. A) 2.2 C° B) 1.5 C° C) 1.1 C° D) 0.50 C° E) 0.15 C°

: E

75) Two metal rods, one silver and the other gold, are attached to each other end-to-end. The free end of the silver rod is immersed in a steam chamber at 100°C, and the free end of the gold rod in an ice water bath at 0°C. The rods are both 5.0 cm long and have a square cross-section that is 2.0 cm on a side. No heat is exchanged between the rods and their surroundings, except at the ends. What is the temperature at the point where the two rods are in contact with one another? The thermal conductivity of silver is 417 W/m ∙ K, and that of gold is 291 W/m ∙ K. A) 39°C B) 41°C C) 47°C D) 53°C E) 59°C

: E

8) Nitrogen boils at -196°C. What is the corresponding temperature in the Fahrenheit scale? A) -315°F B) -196°F C) -346°F D) -290°F E) -321°F

: E

82) The cylindrical filament in a light bulb has a diameter of 0.050 mm, an emissivity of 1.0, and a temperature of 3000°C. How long should the filament be in order to radiate 60 W of power? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 11 cm B) 9.4 cm C) 8.6 cm D) 7.2 cm E) 5.9 cm

: E

heat of fusion

Amount of energy required to change a substance from the solid phase to the liquid phase.

Coefficient of Performance (COP)

COP= Qh/W

2nd law of thermodynamics (Energy)

In any natural process, some energy becomes unavailable to do useful work

Ideal Gas Law

PV=nRT

latent heat formula

Q=mL

heat of vaporization

The amount of energy required for the liquid at its boiling point to become a gas

specific heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius ( Q= mcT)

Conduction

The direct transfer of heat from one substance to another substance that it is touching.

Heat

The energy transferred between objects that are at different temperatures

2nd law of thermodynamics (entropy)

The total entropy of an isolated system never decreases

Convection

The transfer of heat by the movement of a fluid

Entropy

natural processes tend to move towards a state of greater disorder

Adiabatic process

no heat exchange (Q=0) ΔU = -W

entropy equation

ΔS=Q/T (in K)

Carnot (ideal) efficiency

1-Tl/TH

18) The work done on an ideal gas system in an isothermal process is -400 J. What is the change in internal (thermal) energy of the gas? A) 0 J B) -400 J C) 400 J D) 200 J

: A

25) A 2294-kg sample of water at 0° C is cooled to and freezes in the process. How much heat is liberated? For water LF = 334,000 J/kg and LV = 2.256 × 106 J/kg. The specific heat of ice is 2050 J/kg ∙ K. A) 935,000 kJ B) 597,000 kJ C) 1,110,000 kJ D) 334,000 kJ

: A

33) Heat is added to a 3.0 kg piece of ice at a rate of How long will it take for the ice at 0.0° C to melt? For water LF = 334,000 J/kg and LV = 2.246 × 106 J/kg. A) 1.6 s B) 640,000 s C) 0.0 s D) 1000 s

: A

37) A 771.0-kg copper bar is put into a smelter for melting. The initial temperature of the copper is 300.0 K. How much heat must the smelter produce to completely melt the copper bar? The specific heat for copper is 386 J/kg∙K, the heat of fusion for copper is 205,000 J/kg, and its melting point is 1357 K. A) 4.73 × 105 kJ B) 3.15 × 1011 kJ C) 3.15 × 108 kJ D) 5.62 × 105 kJ

: A

43) A gas follows the pV trajectory shown in Figure 16.2. How much work is done per cycle by the gas if The gas in a heat engine follows the cycle shown in the pV diagram. How much work does this engine do each cycle if p0 = A) 220 J B) 440 J C) 870 J D) 1100 J

: A

47) An ideal Carnot heat engine has an efficiency of 0.600. If it operates between a deep lake with a constant temperature of and a hot reservoir, what is the temperature of the hot reservoir? A) 735 K B) 490 K C) 470 K D) 784 K

: A

72) At what temperature would the root mean square speed of oxygen molecules, O2, be if oxygen behaves like an ideal gas? The mass of one O2 molecule is 5.312 × 10-26 kg, and the Boltzmann constant is 1.38 × 10-23 J/K. A) 0.251 K B) 2090 K C) 6270 K D) 1.52 × 1023 K

: A

87) An irreversible engine operating between the temperatures of 550 K and 300 K extracts 1.20 kJ of heat from the hot reservoir and produces 0.450 kJ of work. How much entropy is created in the process? A) 0.32 J/K B) 0.68 J/K C) 0.44 J/K D) 0.73 J/K E) 0 J/K

: A

9) A carpenter is driving a 15.0-g steel nail into a board. His 1.00-kg hammer is moving at 8.50 m/s when it strikes the nail. Half of the kinetic energy of the hammer is transformed into heat in the nail and does not flow out of the nail. What is the increase in temperature of the nail after the three blows that the carpenter needs to drive the nail in completely? The specific heat of steel is 448 J/kg ∙ K. A) 8.1 K B) 3.6 K C) 1.8 K D) 2.7 K E) 7.7 K

: A

1) The figure shows a pV diagram for 2.6 g of ideal helium gas that undergoes the process 1 → 2 → 3. Find the value of volume V3. The atomic mass of helium is 4.0 g/mol, and R = 8.31 J/mol ∙ K. A) 25 L B) 99 L C) 50 L D) 12 L

: A

1) When a gas expands adiabatically, A) the internal (thermal) energy of the gas decreases. B) the internal (thermal) energy of the gas increases. C) it does no work. D) work is done on the gas. E) the temperature of the gas remains constant.

: A

10) Platinum melts at 3215°F. What is the corresponding temperature in the Kelvin scale? A) 2041 K B) 2135 K C) 2207 K D) 2296 K E) 3215 K

: A

10) The figure shows a pV diagram for an ideal gas that is carried around a cyclic process. How much work is done in one cycle if p0 = and L? (1.00 atm = 101 kPa) A) 1210 J B) 485 J C) 2280 J D) 2420 J E) 4850 J

: A

11) A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the change in the internal (thermal) energy of the gas? A) 800 J B) -800 J C) 400 J D) 0 J E) More information is needed to answer this question.

: A

12) If, with steady state heat flow established, you double the thickness of a wall built from solid uniform material, the rate of heat loss for a given temperature difference across the thickness will A) become one-half its original value. B) also double. C) become one-fourth its original value. D) become 1/ of its original value. E) become four times its original value.

: A

13) An aluminum rod 17.400 cm long at 20°C is heated to 100°C. What is its new length? Aluminum has a linear expansion coefficient of 25 × 10-6 K-1. A) 17.435 cm B) 17.365 cm C) 0.348 cm D) 0.0348 cm

: A

14) A 6.5-g iron meteor hits the earth at a speed of 295 m/s. If its kinetic energy is entirely converted to heat in the meteor, by how much will its temperature rise? The specific heat of iron is 113 cal/kg ∙ C°, and 1 cal = 4.186 J. A) 92.0 C° B) 57,100 C° C) 0.147 C° D) 384 C°

: A

16) During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the change in internal (thermal) energy of the gas? A) 0 J B) 2.5 J C) 5.0 J D) 10 J

: A

16) On his honeymoon, James Joule attempted to explore the relationships between various forms of energy by measuring the rise of temperature of water which had fallen down a waterfall on Mount Blanc. What maximum temperature rise would one expect for a waterfall with a vertical drop of 20 m? The specific heat of water is 4186 J/kg ∙ K. A) 0.047 C° B) 0.053 C° C) 0.064 C° D) 0.071 C°

: A

17) If the efficiency of a Carnot engine were to be 100%, the heat sink would have to be A) at absolute zero. B) at 0°C. C) at 100°C. D) infinitely hot.

: A

2) The figure shows a pV diagram for 8.3 g of ideal nitrogen gas N2 in a sealed container. The temperature of state 1 is 59°C, the atomic mass of the nitrogen atom is 14 g/mol, and R = 8.31 J/mol ∙ K. What are (a) pressure p1 and (b) temperature T2? A) (a) 81 atm, (b) 660°C B) (a) 14 atm, (b) 660°C C) (a) 81 atm, (b) 120°C D) (a) 14 atm, (b) 120°C

: A

23) If you add 700 kJ of heat to 700 g of water originally at 70.0°C, how much water is left in the container? The latent heat of vaporization of water is 22.6 × J/kg, and its specific heat capacity is 4186 J/kg ∙ K. A) 429 g B) 258 g C) 340 g D) 600 g E) none

: A

3) A person consumes a snack containing 14 food calories (14 kcal). What is the power this food produces if it is to be "burned off" due to exercise in 6 hours? (1 cal = 4.186 J) A) 2.7 W B) 9763 W C) 0.6 W D) 0.0027 W

: A

31) An aluminum rod is 10.0 cm long and a steel rod is 80.0 cm long when both rods are at a temperature of 15°C. Both rods have the same diameter. The rods are now joined end-to-end to form a rod 90.0 cm long. If the temperature is now raised from 15°C to 90°C, what is the increase in the length of the joined rod? The coefficient of linear expansion of aluminum is 2.4 × 10-5 K-1 and that of steel is 1.2 × 10-5 K-1. A) 0.90 mm B) 0.81 mm C) 0.72 mm D) 0.63 mm E) 0.99 mm

: A

32) A brass rod is 69.5 cm long and an aluminum rod is 49.3 cm long when both rods are at an initial temperature of 0° C. The rods are placed in line with a gap of 1.2 cm between them, as shown in the figure. The distance between the far ends of the rods is maintained at 120.0 cm throughout. The temperature of both rods is raised equally until they are barely in contact. At what temperature does contact occur? The coefficients of linear expansion of brass and aluminum are 2.0 ×10-5 K-1 (brass) and 2.4 × 10-5 K-1 (aluminum). A) 470°C B) 440°C C) 420°C D) 490°C E) 510°C

: A

34) A .20-kg ice cube at 0.0°C has sufficient heat added to it to cause total melting, and the resulting water is heated to How much heat is added? For water LF = 334,000 J/kg, LV = 2.256 × 106 J/kg, the c = 4.186 x 103 J/kg ∙ C. A) 130 kJ B) 14,000 kJ C) 81 kJ D) 59 kJ

: A

34) A heat engine with an efficiency of 30% performs 2500 J of work. How much heat is discharged to the lower temperature reservoir? A) 5800 J B) 8300 J C) 750 J D) 1400 J E) 7100 J

: A

35) How much heat must be added to a 8.0-kg block of ice at -8°C to change it to water at The specific heat of ice is 2050 J/kg ∙ C°, the specific heat of water is 4186 J/kg ∙ C°, the latent heat of fusion of ice is 334,000 J/kg, and 1 cal = 4.186 J. A) 780 kcal B) 140 kcal C) 180 kcal D) 810 kcal E) 730 kcal

: A

36) When a sample of water at 0.0°C is cooled to -36.0°C and freezes in the process, 935,000 kJ of heat is liberated. What is the mass of this sample of water? For water LF = 334,000 J/kg, LV = 2.256 × 106 J/kg, and the specific heat of ice is 2050 J/kg ∙ C°. A) 2290 kg B) 1145 kg C) 2800 kg D) 12,700 kg

: A

38) A substance has a melting point of 20°C and a heat of fusion of 3.4 × J/kg. The boiling point is and the heat of vaporization is at a pressure of one atmosphere. The specific heats for the solid, liquid, and gaseous phases are 600 J/kg ∙ K (solid), 1000 J/kg ∙ K (liquid), and 400 J/kg ∙ K (gaseous). How much heat is required to raise the temperature of of this substance from to at a pressure of one atmosphere? A) 260 kJ B) 190 kJ C) 230 kJ D) 92 kJ E) 320 kJ

: A

39) A substance has a melting point of 20°C and a heat of fusion of The boiling point is and the heat of vaporization is at a pressure of one atmosphere. The specific heats for the solid, liquid, and gaseous phases are 600 J/kg ∙ K (solid), 1000 J/kg ∙ K (liquid), and 400 J/kg ∙ K (gaseous). How much heat is given up by of this substance when it is cooled from 170°C to 86°C at a pressure of one atmosphere? A) 400 kJ B) 200 kJ C) 300 kJ D) 440 kJ E) 640 kJ

: A

4) The figure shows a pV diagram for 0.98 mol of ideal gas that undergoes the process 1 → 2. The gas then undergoes an isochoric heating from point 2 until the pressure is restored to the value it had at point 1. What is the final temperature of the gas? (R = 8.31 J/mol ∙ K). A) -160°C B) 12°C C) 380°C D) 110°C

: A

40) A person tries to heat up her bath water by adding 5.0 L of water at 80°C to 60 L of water at 30°C. What is the final temperature of the bath water? A) 34°C B) 36°C C) 38°C D) 40°C

: A

41) A nuclear power plant has an actual efficiency of 33%. If of energy are released from fission, how much electric power does the power plant produce? A) 0.063 MW B) 6.3 MW C) 25 MW D) 0.25 MW

: A

43) A 90-g aluminum calorimeter contains 390 g of water at an equilibrium temperature of A piece of metal, initially at is added to the calorimeter. The final temperature at equilibrium is 32° C. Assume there is no external heat exchange. The specific heat capacities of aluminum and water are 910 J/kg ∙ K (aluminum) and 4190 J/kg ∙ K (water). What is the specific heat capacity of the 160-g piece of metal? A) 470 J/kg ∙ K B) 430 J/kg ∙ K C) 350 J/kg ∙ K D) 310 J/kg ∙ K E) 510 J/kg ∙ K

: A

45) A lab student drops a 400.0-g piece of metal at 120.0°C into a cup containing 450.0 g of water at 15.0°C. After waiting for a few minutes, the student measures that the final temperature of the system is 40.0°C. What is the specific heat of the metal, assuming that no significant heat is exchanged with the surroundings or the cup? The specific heat of water is 4186 J/kg ∙ K. A) 1470 J/kg ∙ K B) 2830 J/kg ∙ K C) 3420 J/kg ∙ K D) 3780 J/kg ∙ K E) 4280 J/kg ∙ K

: A

46) An ideal Carnot heat engine operates between and What is its efficiency? A) 0.38 B) 0.62 C) 0.61 D) 1.61

: A

47) A jogger is running outdoors on a cold day when the temperature is -20.0°C. She is breathing at the rate of 25 breaths per minute, and each time she breathes in she inhales 0.00450 m3 of air. How much heat does she lose from breathing during 20.0 minutes of jogging if the air in her lungs is heated to her body temperature of 37.0°C before it is exhaled? The specific heat of air is 1020 J/kg ∙ K and the density of air under typical conditions is 1.29 kg/m3. A) 169 kJ B) 278 kJ C) 354 kJ D) 431 kJ E) 543 kJ

: A

48) An ideal Carnot engine extracts 529 J of heat from a high-temperature reservoir during each cycle, and rejects of heat to a low-temperature reservoir during the same cycle. What is the efficiency of the engine? A) 0.57 B) 1.35 C) 2.35 D) 0.7

: A

49) A laboratory vacuum pump can reduce the pressure in a chamber to 1.0 × 10-7 Pa. If the volume of the chamber is 0.500 m3 and the temperature is 27°C, how many molecules are left inside the chamber? (NA = 6.022 × 1023 molecules/mol, R = 8.31 J/mol ∙ K) A) 1.2 × 1013 B) 2.4 × 1013 C) 1.2 × 1012 D) 2.4 × 1012 E) 1.2 × 1014

: A

50) A 0.600-kg piece of metal X is heated to 100°C and placed in an aluminum can of mass 0.200-kg which contains 0.500 kg of water initially at 17.3°C. The final equilibrium temperature of the mixture is 20.2°C, what is the specific heat of metal X? The specific heats of water and aluminum are 4186 J/kg ∙ K (water) and 910 J/kg ∙ K (aluminum). A) 140 J/kg ∙ K B) 270 J/kg ∙ K C) 450 J/kg ∙ K D) 900 J/kg ∙ K

: A

53) An ideal Carnot engine has an efficiency of 83.0% and performs 4500 J of work every cycle. How much energy is discharged to the lower temperature reservoir every cycle? A) 920 J B) 830 J C) 740 J D) 3700 J E) 5400 J

: A

54) A 5.3 L flask of ideal neon gas (which is monatomic) is at a pressure of 6.0 atm and a temperature of The atomic mass of neon is 20.2 g/mol. What is the mass of the neon gas in the flask. (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa, NA = 6.022 × 1023 molecules/mol) A) 2.7 × 10-2 B) 1.6 × 10-2 C) 1.3 × 101 D) 2.7 × 101 E) 2.7 × 103

: A

55) A 4.2-L flask of ideal neon gas (which is monatomic) is at a pressure of 3.3 atm and a temperature of 450 K. The atomic mass of neon is 20.2 g/mol. How many neon atoms are in the flask? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa, NA = 6.022 × 1023 molecules/mol) A) 2.3 × 1023 B) 2.3 × 1022 C) 6.9 × 1023 D) 2.3 × 1025 E) 6.9 × 1022

: A

57) A 0.40- gas tank holds 7.0 moles of ideal diatomic nitrogen gas at a temperature of The atomic mass of nitrogen is . What is the pressure of the gas? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa) A) 42 atm B) 37 atm C) 32 atm D) 27 atm E) 22 atm

: A

57) A 400-g block of iron at 400°C is dropped into a calorimeter (of negligible heat capacity) containing 60 g of water at 30°C. How much steam is produced? The latent heat of vaporization of water is 22.6 × 105 J/kg and its specific heat capacity is 4186 J/kg ∙ K. The average specific heat of iron over this temperature range is 560 J/kg ∙ K. A) 22 g B) 33 g C) 42 g D) 54 g E) 59 g

: A

59) A 360-g metal container, insulated on the outside, holds 180.0 g of water in thermal equilibrium at 22.0°C. A 24.0-g ice cube, at the melting point, is dropped into the water, and when thermal equilibrium is reached the temperature is 15.0°C. Assume there is no heat exchange with the surroundings. For water, the specific heat capacity is 4190 J/kg ∙ K and the heat of fusion is 3.34 × 105 J/kg. What is the specific heat capacity of the metal of the container? A) 1700 J/kg ∙ K B) 970 J/kg ∙ K C) 2300 J/kg ∙ K D) 2800 J/kg ∙ K E) 3300 J/kg ∙ K

: A

59) An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at has an efficiency of What is the temperature of the warm reservoir? A) 2.93 K B) 0.0500 K C) 106 K D) 0.0400 K

: A

6) The figure shows a pV diagram for 0.0077 mol of ideal gas that undergoes the process 1 → 2 → 3. What is the volume V3? (R = 8.31 J/mol ∙ K) the volume V3? A) 770 B) 0 C) 0 D) 400

: A

60) An ideal Carnot engine operates between a warm reservoir at 233 K and a colder reservoir. During each cycle, this engine extracts of heat from the warm reservoir and does of work. What is the temperature of the colder reservoir? A) 171 K B) 62 K C) 47 K D) 67 K

: A

61) What is the efficiency of an ideal Carnot engine operating between a reservoir in which ice and water coexist, and a reservoir in which water and steam coexist? The pressure is constant at 1.0 atm for both reservoirs. A) 27% B) 0.27% C) 100% D) 1.0% E) 15%

: A

62) An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at has an efficiency of What is the temperature of the warm reservoir? A) 1.98 K B) 0.180 K C) 157 K D) 0.160 K

: A

63) A heat-conducting rod, 0.90 m long and wrapped in insulation, is made of an aluminum section that is 0.20 m long and a copper section that is long. Both sections have a cross-sectional area of The aluminum end and the copper end are maintained at temperatures of and respectively. The thermal conductivities of aluminum and copper are 205 W/m ∙ K (aluminum) and 385 W/m ∙ K (copper). What is the temperature of the aluminum-copper junction in the rod with steady state heat flow? A) 100°C B) 93°C C) 86°C D) 80°C E) 74°C

: A

64) A heat conducting rod, 1.60 m long and wrapped in insulation, is made of an aluminum section that is 0.90 m long and a copper section that is long. Both sections have a cross-sectional area of The aluminum end and the copper end are maintained at temperatures of and respectively. The thermal conductivities of aluminum and copper are 205 W/m ∙ K (aluminum) and 385 W/m ∙ K (copper). At what rate is heat conducted in the rod under steady state conditions? A) 9.0 W B) 7.9 W C) 10 W D) 11 W E) 12 W

: A

65) A Carnot engine operates between two reservoirs with unknown temperatures. If the Carnot engine operates at efficiency, what is the ratio of the absolute temperatures of the reservoirs, Tc/Th? A) 0.33 B) 0.0012 C) 0.0025 D) 0.67

: A

71) A 0.50 gas tank holds 3.0 moles of ideal diatomic nitrogen gas at a temperature of The atomic mass of nitrogen is . What is the rms speed of the molecules? (The Boltzmann constant is 1.38 × 10-23 J/K, NA = 6.022 × 1023 molecules/mol.) A) 560 B) 790 C) 390 D) 21 E) 97

: A

73) If the temperature of a gas is increased from 20°C to 100°C, by what factor does the rms speed of an ideal molecule change? A) 1.1 B) 1.3 C) 2.2 D) 1.6

: A

74) Two metal rods, one silver and the other gold, are attached to each other end-to-end. The free end of the silver rod is immersed in a steam chamber at 100°C, and the free end of the gold rod in an ice water bath at 0°C. The rods are both 5.0 cm long and have a square cross-section that is 2.0 cm on a side. No heat is exchanged between the rods and their surroundings, except at the ends. How much total heat flows through the two rods each minute? The thermal conductivity of silver is 417 W/m ∙ K, and that of gold is 291 W/m ∙ K. A) 8.2 kJ B) 9.5 kJ C) 12 kJ D) 14 kJ E) 16 kJ

: A

80) An ideal Carnot engine is operated as a heat pump to heat a room in the winter. The heat pump delivers heat to the room at the rate of 47 kJ per second and maintains the room at a temperature of 293 K when the outside temperature is 237 K. The power requirement to run the heat pump under these operating conditions is closest to A) 9000 W. B) 7100 W. C) 20,000 W. D) 15,000 W. E) 11,000 W.

: A

87) The radius of a star is 6.95 × 108 m, and its rate of radiation has been measured to be 5.32 × 1026 W. Assuming that it is a perfect emitter, what is the temperature of the surface of this star? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 6.27 × 103 K B) 8.25 × 103 K C) 8.87 × 103 K D) 3.93 × 107 K E) 5.78 × 107 K

: A

90) A 0.42-kg quantity of ethanol, in the liquid state at its melting point of -114.4°C, is frozen at atmospheric pressure. The heat of fusion of ethanol is 1.04 × 105 J/kg, and its molecular mass is 46.1 g/mol. What is the change in the entropy of the ethanol as it freezes? A) -280 J/K B) -250 J/K C) -310 J/K D) 250 J/K E) 280 J/K

: A

13) The process in which heat flows by the mass movement of molecules from one place to another is known as A) conduction. B) convection. C) radiation.

: B

14) A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle, as shown in the pV diagram in the figure. If the process is carried out in a counter-clockwise sense around the enclosed area, as shown on the figure, then the magnitude of the enclosed area represents A) the heat that flows out of the gas. B) the work done on the gas. C) the heat added to the gas. D) the work done by the gas.

: B

19) For the mercury in a thermometer to expand from 4.00 cm3 to 4.10 cm3, what change in temperature is necessary? The mercury has a volume expansion coefficient of 1.80 × 10-4 K-1. A) 400 C° B) 140 C° C) 14 C° D) 8.2 C°

: B

28) Solar houses use a variety of energy storage devices to retain the heat absorbed during the day so that it can be released during the night. Suppose that you were to use a device of this kind to produce steam at 100°C during the day, and then allow the steam to cool to 0°C and freeze during the night. How many kilograms of water would be needed to store 20.0 kWh of energy in this way? The latent heat of vaporization of water is 22.6 × 105 J/kg, the latent heat of fusion of water is 33.5 × 104 J/kg, and the specific heat capacity of water is 4186 J/kg ∙ K. A) 12.4 kg B) 23.9 kg C) 35.7 kg D) 42.6 kg E) 54.2 kg

: B

51) The ocean thermal energy conversion project uses the surface water near tropical islands with a temperature of 20°C as the hot temperature reservoir, and the water at some depth, with a temperature of 5.0°C, as the cold temperature reservoir for a heat engine. What is the maximum possible efficiency of an engine running between those two temperatures? A) 4.7% B) 5.1% C) 7.9% D) 15% E) 30%

: B

76) At what temperature would the root-mean-square speed of hydrogen, H2, molecules equal 11.2 km/s (the earth's escape speed)? The mass of a hydrogen atom is 1.67 × 10-27 kg, and the Boltzmann constant is 1.38 × 10-23 J/K. A) 1.01 × 102 K B) 1.01 × 104 K C) 1.01 × 106 K D) 1.01 × 108 K

: B

76) The thermal conductivity of a certain concrete is 0.80 W/m . K and the thermal conductivity of a certain wood is 0.10 W/m ∙ K. How thick would a solid concrete wall have to be in order to have the same rate of heat flow through it as an 8.0-cm thick wall made of solid wood? Both walls have the same surface area and the same temperature difference across their faces. A) 53 cm B) 64 cm C) 71 cm D) 85 cm

: B

1) If you wanted to know how much the temperature of a particular piece of material would rise when a known amount of heat was added to it, which of the following quantities would be most helpful to know? A) initial temperature B) specific heat C) density D) coefficient of linear expansion E) thermal conductivity

: B

13) A gas expands from an initial volume of 0.040 m3 to a final volume of 0.085 m3 while its pressure increases linearly with the volume (so that the process follows a straight-line path in a pV diagram) from 110 kPa to 225 kPa. How much work is done by the gas during this expansion? A) 5.2 kJ B) 7.5 kJ C) 7.8 kJ D) 11 kJ E) 12 kJ

: B

14) By what length will a slab of concrete that is originally 18 m long contract when the temperature drops from 24°C to -16°C? The coefficient of linear thermal expansion for this concrete is 1.0 × 10-5 K-1. A) 0.50 cm B) 0.72 cm C) 1.2 cm D) 1.5 cm

: B

16) Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, how do their average molecular speeds compare? The oxygen molecules are moving A) four times faster than the hydrogen molecules. B) at 1/4 the speed of the hydrogen molecules. C) sixteen times faster than the hydrogen molecules. D) at 1/16 the speed of the hydrogen molecules. E) at 1/ the speed of the hydrogen molecules.

: B

16) The second law of thermodynamics leads us to conclude that A) the total energy of the universe is constant. B) disorder in the universe is increasing with the passage of time. C) it is theoretically possible to convert heat into work with 100% efficiency. D) the average temperature of the universe is increasing with the passage of time. E) the entropy of the universe remains constant.

: B

17) A large vat contains 1.000 L of water at 20°C. What volume will this water occupy when it is heated up to 80°C? Water has a volume expansion coefficient of 210 × 10-6 K-1. A) 1.600 L B) 1.013 L C) 0.987 L D) 0.9987 L

: B

20) In grinding a steel knife, the metal can get as hot as 400°C. If the blade has a mass of 80 g, what is the minimum amount of water needed at 20°C if the water is to remain liquid and not rise above 100°C when the hot blade is quenched in it? The specific heat of the steel is 0.11 cal/g ∙ C° and the specific heat of water is 1.0 cal/g ∙ C°. A) 22 g B) 33 g C) 44 g D) 55 g

: B

21) The coefficient of linear expansion of copper is 17 × 10-6 K-1. A sheet of copper has a round hole with a radius of 3.0 m cut out of it. If the sheet is heated and undergoes a change in temperature of 80 K, what is the change in the radius of the hole? A) It decreases by 4.1 mm. B) It increases by 4.1 mm. C) It decreases by 8.2 mm. D) It increases by 8.2 mm. E) It does not change.

: B

22) A runner generates 1260 W of thermal energy. If this heat has to be removed only by evaporation, how much water does this runner lose in 15 minutes of running? The latent heat of vaporization of water is 22.6 × 105 J/kg. A) 50 g B) 500 g C) 35 g D) 350 g E) 40 g

: B

29) The coefficient of linear expansion of copper is 17 × 10-6 K-1 and that of steel is 12 × 10-6 K-1. At 12°C a steel rod has a diameter of 2.540 cm and a copper pipe has a diameter of 2.536 cm. If they are heated together to a higher temperature, which one of the following quantities is closest to the common temperature at which the steel rod will fit snugly in the copper pipe? A) 310°C B) 330°C C) 340°C D) 350°C E) 380°C

: B

3) An ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be A) three times as large as the initial value. B) equal to the initial value. C) more than three times as large as the initial value. D) nine times the initial value. E) impossible to predict on the basis of this data.

: B

82) A heat pump with a performance coefficient (COP) of 4.9 absorbs heat from the atmosphere at a rate of At what rate is work being done to run this heat pump? A) 6 kW B) 142 kW C) 113 kW D) 35 kW

: A

81) An ideal Carnot refrigerator with a performance coefficient (COP) of 5.0 cools items inside of it to What is the high temperature needed to operate this refrigerator? A) 61° C B) 1395° C C) 6° C D) 30° C

: A

11) The coefficient of linear expansion of steel is 12 × 10-6 K-1. What is the change in length of a 25-m steel bridge span when it undergoes a temperature change of 40 K from winter to summer? A) 1.2 cm B) 1.4 cm C) 1.6 cm D) 1.8 cm E) 2.0 cm

: A

13) A container of 114.0 g of water is heated using of power, with perfect efficiency. How long will it take to raise the temperature of the water from to The specific heat capacity of the container is negligible, and the specific heat capacity of water is 4.186 × 103 J/kg ∙ C. A) 71 s B) 4.1 s C) 17 s D) 320,000 s

: A

14) The absolute temperature of a gas is T. In order to double the rms speed of its molecules, what should be the new absolute temperature? A) 4T B) 2T C) T D) 8T E) 16T

: A

15) A hole in a brass plate has a diameter of 1.200 cm at 20°C. What is the diameter of the hole when the plate is heated to 220°C? The coefficient of linear thermal expansion for brass is 19 × 10-6 K-1. A) 1.205 cm B) 1.195 cm C) 1.200 cm D) 1.210 cm

: A

33) A certain heat engine extracts 1.30 kJ of heat from a hot temperature reservoir and discharges 0.70 kJ of heat to a cold temperature reservoir. What is the efficiency of this engine? A) 46% B) 54% C) 86% D) 27% E) 13%

: A

33) A glass flask has a volume of 500 mL at a temperature of 20° C. The flask contains 492 mL of mercury at an equilibrium temperature of 20°C. The temperature is raised until the mercury reaches the 500 mL reference mark. At what temperature does this occur? The coefficients of volume expansion of mercury and glass are 18 ×10-5 K-1 (mercury) and 2.0 ×10-5 K-1 (glass). A) 120°C B) 110°C C) 100°C D) 140°C E) 130°C

: A

59) A sealed cylinder fitted with a movable piston contains ideal gas at 27°C, pressure 0.500 × 105 Pa, and volume 1.25 m3. What will be the final temperature if the gas is compressed to 0.800 m3 and the pressure rises to 0.820 × 105 Pa? A) 42°C B) 68°C C) 130°C D) 250°C E) 150°C

: A

68) What is the average translational kinetic energy of a nitrogen molecule in the air in a room in which the air temperature is 17°C? The Boltzmann constant is 1.38 × 10-23 J/K. A) 6.01 × 10-21 J B) 4.00 × 10-21 J C) 5.00 × 10-21 J D) 7.00 × 10-21 J E) 9.00 × 10-21 J

: A

70) A solid concrete wall has dimensions 4.0 m × 2.4 m and is 30 cm thick. The thermal conductivity of the concrete is 1.3 W/m ∙ K, and it separates a basement from the ground outside. The inner surface of the wall is at 18°C, and the outside surface is at 6°C. How much heat flows through the wall every hour? A) 1.8 MJ B) 1.8 kJ C) 500 J D) 5.0 MJ E) 5.0 kJ

: A

1) Express a body temperature 98.6°F in Celsius degrees. A) 37.0°C B) 45.5°C C) 66.6°C D) 72.6°C

: A

11) It is necessary to determine the specific heat of an unknown object. The mass of the object is It is determined experimentally that it takes to raise the temperature What is the specific heat of the object? A) 7.46 J/kg ∙ K B) 1500 J/kg ∙ K C) 0.00130 J/kg ∙ K D) 3,020,000 J/kg ∙ K

: A

12) A 920-g empty iron kettle is put on a stove. How much heat in joules must it absorb to raise its temperature form to The specific heat for iron is 113 cal/kg ∙ C°, and 1 cal = 4.186 J. A) 33,900 J B) 40,500 J C) 8110 J D) 40,100 J

: A

15) A glass beaker of unknown mass contains of water. The system absorbs of heat and the temperature rises as a result. What is the mass of the beaker? The specific heat of glass is 0.18 cal/g ∙ °C, and that of water is 1.0 cal/g ∙ C°. A) 140 g B) 560 g C) 540 g D) 270,000 g

: A

18) In a flask, 114.0 g of water is heated using of power, with perfect efficiency. How long will it take to raise the temperature of the water from to The specific heat of water is 4186 J/kg ∙ K. A) 71 s B) 4.1 s C) 17 s D) 320,000 s

: A

24) The coefficient of linear expansion of aluminum is 24 × 10-6 K-1 and the coefficient of volume expansion of olive oil is 0.68 × 10-3 K-1. A novice cook, in preparation of some pesto, fills a 1.00-L aluminum pot to the brim and heats the oil and the pot from an initial temperature of 15°C to 190°C. To his consternation some olive oil spills over the top. How much? A) 0.11 L B) 0.12 L C) 0.13 L D) 0.14 L E) 0.15 L

: A

26) The melting point of aluminum is 660°C, its latent heat of fusion is 4.00 × 105 J/kg, and its specific heat is 900J/kg ∙ K. How much heat must be added to 500 g of aluminum originally at 27°C to completely melt it? A) 485 kJ B) 395 kJ C) 273 kJ D) 147 kJ E) 14 kJ

: A

30) A steel pipe 36.0 m long, installed when the temperature was is used to transport superheated steam at a temperature of Steel's coefficient of linear expansion is . The pipe is allowed to expand freely when the steam is transported. What is the increase in the length of the pipe when it is used with the superheated steam? A) 60 mm B) 57 mm C) 54 mm D) 64 mm E) 67 mm

: A

32) A 45.0-kg sample of ice is at 0.00° C. How much heat is needed to melt it? For water LF = 334,000 J/kg and LV = 2.256 × 106 J/kg. A) 1.50 × 104 kJ B) 4.10 × 106 kJ C) 0.00 kJ D) 1.02 × 105 kJ

: A

50) A refrigerator has an interior volume of 0.500 m3. The temperature inside the refrigerator in 282 K, and the pressure is 101 kPa. If the molecular weight of air is 29 g/mol, what is the mass of air inside the refrigerator? (R = 8.31 J/mol × K) A) 625 g B) 513 g C) 447 g D) 329 g E) 243 g

: A

55) A 44.0-g block of ice at -15.0°C is dropped into a calorimeter (of negligible heat capacity) containing of water at 5.0°C. When equilibrium is reached, how much of the ice will have melted? The specific heat of ice is 2090 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 2.1 g B) 21 g C) 5.2 g D) 52 g E) 4.4 g

: A

56) A 3.9-L volume of ideal neon gas (monatomic) is at a pressure of 5.6 aym and a temperature of The atomic mass of neon is The temperature of the gas is now increased to 430 K and the volume is increased to What is the final pressure of the gas? A) 4.8 atm B) 4.3 atm C) 5.3 atm D) 5.8 atm E) 6.3 atm

: A

65) What is the average translational kinetic energy of an ideal gas at The Boltzmann constant is 1.38 × 10-23 J/K. A) 1.70 x 10-20 J B) 5.65 x 10-21 J C) 1.13 x 10-17 J D) 3.77 x 10-19 J

: A

67) A glass window pane is 2.7 m high, 2.4 m wide, and 9.0 mm thick. The temperature at the inner surface of the glass is and at the outer surface 4°C. How much heat is lost each hour through the window? A) 3.1 × 107 J B) 3.1 × 104 J C) 8.6 × 103 J D) 8.6 J E) 3.1 × 105 J

: A

75) Dust particles in a grain elevator frequently have masses of the order of 1.0 × 10-9 kg. If, to a first approximation, we model the dust particles as an ideal gas, what would be the rms speed of such a particle in air at 27°C? The Boltzmann constant is 1.38 × 10-23 J/K . A) 3.5 × 10-6 m/s B) 5.6 × 10-5 m/s C) 7.8 × 10-4 m/s D) 5.2 × 10-3 m/s E) 4.9 × 10-2 m/s

: A

77) If the temperature of an ideal gas is increased from 20°C to 40°C, by what percent does the speed of the molecules increase? A) 3% B) 30% C) 70% D) 100%

: A

85) What is the change in entropy when 15.0 g of water at 100°C are turned into steam at 100°C? The latent heat of vaporization of water is 22.6 × 105 J/kg. A) 90.8 J/K B) -90.8 J/K C) 339 J/K D) -339 J/K E) 0 J/K

: A

86) What is the net power radiated by a little animal with a surface area of 0.075 m2 if his emissivity is 0.75, his skin temperature is 315 K, and he is in a room with a temperature of 290 K? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 8.8 W B) 6.0 W C) 8.0 W D) 15 W E) 18 W

: A

88) On a cold winter day, the outside temperature is -20°C and the inside temperature is maintained at 20°C. There is a net heat flow to the outside through the walls, roof, etc., of 25 kW. What is the rate of increase of the entropy of the universe as a result of this heat flow? A) 13 W/K B) 25 W/K C) 85 W/K D) 99 W/K E) 0 W/K

: A

17) The water flowing over Niagara Falls drops a distance of 50 m. If all the gravitational potential energy is converted to thermal energy, by what temperature does the water rise? The specific heat of water is 4186 J/kg ∙ K. A) 0.10 C° B) 0.12 C° C) 0.37 C° D) 0.42 C°

: B

51) A vertical cylinder, closed at the bottom end, contains 0.0100 mol of ideal gas. It is fitted at the top with a piston that can move freely. The mass of the piston is 14.0 kg and the initial height of the piston above the bottom of the cylinder is 25 cm. What is the temperature of the gas? (R = 8.31 J/mol ∙ K) A) 290 K B) 413 K C) 3620 K D) 405 K E) 500 K

: B

65) A heat-conducting rod that is wrapped in insulation is constructed with a 0.15-m length of alloy A and a 0.40-m length of alloy B, joined end-to-end. Both pieces have cross-sectional areas of 0.0020 m2. The thermal conductivity of alloy B is known to be 1.8 times as great as that for alloy A. The end of the rod in alloy A is maintained at a temperature of 10°C, and the other end of the rod is maintained at an unknown temperature. When steady state flow has been established, the temperature at the junction of the alloys is measured to be 40° C, and the rate of heat flow in the rod is measured at 56 W. What is the temperature of the end of the rod in alloy B? A) 80°C B) 84°C C) 88°C D) 92°C E) 96°C

: B

73) Two metal rods, one silver and the other copper, are both immersed at one end in a steam chamber at a temperature of 100°C. The other end of each one is in an ice water bath at 0°C. The rods are 5.0 cm long and have a square cross-section that is 2.0 cm on a side. No heat is exchanged between the rods and the surroundings, except at the ends. How much total heat flows through the two rods each minute? The thermal conductivity of silver is 417 W/m ∙ K, and that of copper is 395 W/m ∙ K. A) 20 kJ B) 39 kJ C) 47 kJ D) 49 kJ E) 11 kJ

: B

83) A heat pump absorbs heat from the atmosphere at a rate of 30 kW. If work is being done to run this heat pump at a rate of 7.7 kW, what is the coefficient of performance (COP) of the heat pump? A) 3.9 B) 4.9 C) 2.9 D) 0.26 E) 22

: B

19) A 200-L electric water heater uses 2.0 kW. Assuming no heat loss, how many hours would it take to heat the water in this tank from 23°C to 75°C? The specific heat of water is 4186 J/kg ∙ K and its density is 1000 kg/m3. A) 5.0. hours B) 6.0 hours C) 7.0 hours D) 8.0 hours

: B

25) The coefficient of volume expansion of a certain olive oil is 0.68 × 10-3 K-1. A 1.0-L glass beaker is filled to the brim with olive oil at room temperature. The beaker is placed on a range and the temperature of the oil and beaker increases by 25 C°. As a result, 0.0167 L of olive oil spills over the top of the beaker. Which of the following values is closest to the coefficient of linear expansion of the glass from which the beaker is made? A) 1 × 10-6 K-1 B) 4 × 10-6 K-1 C) 1 × 10-5 K-1 D) 2 × 10-5 K-1 E) 3 × 10-5 K-1

: B

27) The density of water at 0°C is 999.84 kg/m3 and at 4°C it is 999.96 kg/m3. A 1.0-L container, full to the brim with water at 4.0°C is placed in the refrigerator. By the time that the temperature of the water reaches 0.0°C, what volume of water has spilled from the container, assuming that the contraction of the container is negligible? A) 1.1 × 10-7 m3 B) 1.2 × 10-7 m3 C) 1.3 × 10-7 m3 D) 1.4 × 10-7 m3 E) 1.5 × 10-7 m3

: B

39) How many moles are there in 2.00 kg of copper? The atomic weight of copper is 63.5 g/mol and its density is 8.90 g/cm3. A) 15.3 B) 31.5 C) 51.3 D) 53.1

: B

40) An ideal gas has a pressure of 2.5 atm, a volume of 1.0 L at a temperature of 30°C. How many molecules are there in this gas? (R = 8.31 J/mol ∙ K,1.00 atm = 101 kPa, NA = 6.022 × 1023) A) 6.1 × 1023 B) 6.0 × 1022 C) 2.4 × 1022 D) 2.3 × 1023

: B

42) A lab assistant pours 330 g of water at 45°C into an 855-g aluminum container that is at an initial temperature of 10°C. The specific heat of aluminum is and that of water is 4186 J/kg ∙ K. What is the final temperature of the system, assuming no heat is exchanged with the surroundings? A) 28°C B) 32°C C) 31°C D) 33°C E) 35°C

: B

44) A certain automobile tire has a volume of 0.0185 m3. If the absolute (or total) pressure in the tire is 500 kPa and the temperature is 298 K, how many molecules are there inside the tire? (R = 8.31 J/mol ∙ K, NA = 6.022 x 1023 molecules/mol) A) 2.25 × 1023 molecules B) 2.25 × 1024 molecules C) 3.25 × 1023 molecules D) 3.25 × 1024 molecules E) 3.25 × 1025 molecules

: B

46) A lab assistant drops a 400.0-g piece of metal at 100.0°C into a 100.0-g aluminum cup containing 500.0 g of water at In a few minutes, she measures the final temperature of the system to be 40.0°C. What is the specific heat of the 400.0-g piece of metal, assuming that no significant heat is exchanged with the surroundings? The specific heat of this aluminum is 900.0 J/kg ∙ K and that of water is 4186 J/kg ∙ K. A) 1900 J/kg ∙ K B) 2270 J/kg ∙ K C) 3300 J/kg ∙ K D) 3800 J/kg ∙ K E) 4280 J/kg ∙ K

: B

5) At what, if any, temperature are the numerical readings on the Fahrenheit and Celsius scales the same? A) -30° B) -40° C) -50° D) -60° E) They can never read the same because they are based on different zeroes.

: B

60) Two experimental runs are performed to determine the calorimetric properties of an alcohol which has a melting point of -10.0° C. In the first run, a 200-g cube of frozen alcohol, at the melting point, is added to 300 g of water at 20.0°C in a styrofoam container. When thermal equilibrium is reached, the alcohol-water solution is at a temperature of 5.0°C. In the second run, an identical cube of alcohol is added to 500 g of water at 20.0°C and the temperature at thermal equilibrium is 10.0°C. The specific heat capacity of water is 4190 J/kg ∙ K. Assume no heat is exchanged with the styrofoam container and the surroundings. What is the heat of fusion of the alcohol? A) 5.5 × 104 J/kg B) 6.3 × 104 J/kg C) 7.1 × 104 J/kg D) 7.9 × 104 J/kg E) 8.7 × 104 J/kg

: B

77) The thermal conductivity of aluminum is twice that of brass. Two rods (one aluminum and the other brass) of the same length and cross-sectional area are joined together end to end. The free end of the brass rod is maintained at 0°C and the free end of the aluminum rod is maintained at 200°C. If no heat escapes from the sides of the rods, what is the temperature at the place where the two rods are joined together? A) 76°C B) 133°C C) 148°C D) 155°C

: B

78) If an ideal gas molecule has a speed of 0.50 km/s at 20°C, what is its speed at 80°C? A) 500 m/s B) 550 m/s C) 1000 m/s D) 2000 m/s

: B

10) A mole of diatomic oxygen molecules and a mole of diatomic nitrogen molecules are at STP. Which statements are true about these molecules? (There could be more than one correct choice.) A) Both gases have the same average molecular speeds. B) Both gases have the same number of molecules. C) Both gases have the same average kinetic energy per molecule. D) Both gases have the same average momentum per molecule.

: B, C

48) A person is walking outdoors on a cold day when the temperature is -20°C. He is breathing at the rate of 16 breaths per minute, and each time he breathes in he inhales 0.0050 m3 of air. At what rate does he lose heat from breathing if the air in his lungs is heated to body temperature (37°C) before it is exhaled? The specific heat of air is 1020 J/kg ∙ K and the density of air is 1.29 kg/m3. A) 60 W B) 90 W C) 100 W D) 150 W E) 300 W

: C

52) A person makes iced tea by adding ice to 1.8 kg of hot tea, initially at 80°C. How many kilograms of ice, initially at 0°C, are required to bring the mixture to 10°C? The specific heat of water (and tea) is 4186 J/kg ∙ K, and the latent heat of fusion of ice is 3.34 × 105 J/kg. A) 1.0 kg B) 1.2 kg C) 1.4 kg D) 1.7 kg

: C

1) At room temperature, a typical person loses energy to the surroundings at the rate of 62 W. If this energy loss has to be made up by an equivalent food intake, how many kilocalories (food calories) does this person need to consume every day just to make up this heat loss? (1 cal = 4.186 J) A) 1000 kcal B) 1100 kcal C) 1300 kcal D) 1500 kcal E) 1600 kcal

: C

1) Which two temperature changes are equivalent? A) 1 K = 1 F° B) 1 F° = 1 C° C) 1 C° = 1 K D) none of the above

: C

12) A sample of an ideal gas is heated and its Kelvin temperature doubles. If the root-mean-square speed of its molecules was originally v, what is the new root-mean-square speed? A) 4v B) 2v C) v D) v/ E) v/4

: C

13) The absolute temperature of an ideal gas is directly proportional to which of the following quantities? A) the average speed of its molecules B) the average momentum of its molecules C) the average kinetic energy of its molecules D) the mass of its molecules E) It is proportional to all of the above quantities.

: C

15) Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, the average molecular kinetic energy of oxygen molecules, compared to that of hydrogen molecules, A) is greater. B) is less. C) is the same. D) cannot be determined without knowing the pressure and volume.

: C

16) A quantity of mercury occupies 400.0 cm3 at 0°C. What volume will it occupy when heated to 50°C? Mercury has a volume expansion coefficient of 180 × 10-6 K-1. A) 450 cm3 B) 409.7 cm3 C) 403.6 cm3 D) 401.8 cm3

: C

18) The volume coefficient of thermal expansion for gasoline is 950 × 10-6 K-1. By how many cubic centimeters does the volume of 1.00 L of gasoline change when the temperature rises from 30°C to 50°C? A) 6.0 cm3 B) 12 cm3 C) 19 cm3 D) 37 cm3

: C

2) Express -40°C in °F. A) -72°F B) -54°F C) -40°F D) 4.4°F

: C

20) A mercury thermometer has a glass bulb of interior volume 0.100 cm3 at 10°C. The glass capillary tube above the bulb has an inner cross-sectional area of 0.012 mm2. The coefficient of volume expansion of mercury is 1.8 × 10-4 K-1. If the expansion of the glass is negligible, how much will the mercury rise in the capillary tube when the temperature rises from 5°C to 35°C if the bulb was full at 5°C? A) 0.45 mm B) 4.5 mm C) 45 mm D) 45 cm

: C

4) A temperature change of 20 C° corresponds to a Fahrenheit temperature change of A) 68 F°. B) 11 F°. C) 36 F°. D) 18 F°.

: C

5) The coefficient of linear expansion for aluminum is 1.8 × 10-6 K-1. What is its coefficient of volume expansion? A) 9.0 × 10-6 K-1 B) 5.8 × 10-18 K-1 C) 5.4 × 10-6 K-1 D) 3.6 × 10-6 K-1 E) 0.60 × 10-6 K-1

: C

52) A gas-filled vertical cylinder, closed at the bottom end, is fitted at the top with a piston that can move freely. The mass of the piston is 10.0 kg, and the initial height of the piston above the bottom of the cylinder is 25 cm. A mass of 8.0 kg is placed on the piston. What is the resulting height of the piston, assuming that the temperature of the ideal gas is kept constant? A) 12 cm B) 13 cm C) 14 cm D) 15 cm E) 16 cm

: C

53) A quantity of an ideal gas is kept in a rigid container of constant volume. If the gas is originally at a temperature of 19°C, at what temperature will the pressure of the gas double from its original value? A) 91°C B) 38°C C) 311°C D) 273°C E) 122°C

: C

6) Two metal spheres are made of the same material and have the same diameter, but one is solid and the other is hollow. If their temperature is increased by the same amount, A) the solid sphere becomes bigger than the hollow one. B) the hollow sphere becomes bigger than the solid one. C) the two spheres remain of equal size. D) the solid sphere becomes denser and the hollow one less dense. E) the solid sphere becomes less dense and the hollow one denser.

: C

61) Two experimental runs are performed to determine the calorimetric properties of an alcohol which has a melting point of -10° C. In the first run, a 200-g cube of frozen alcohol, at the melting point, is added to 300 g of water at 20°C in a styrofoam container. When thermal equilibrium is reached, the alcohol-water solution is at a temperature of 5°C. In the second run, an identical cube of alcohol is added to 500 g of water at 20°C and the temperature at thermal equilibrium is 10°C. The specific heat capacity of water is 4190 J/kg ∙ K. Assume no heat is exchanged with the styrofoam container and the surroundings. What is the specific heat capacity of the alcohol? A) 1700 J/kg ∙ K B) 1900 J/kg ∙ K C) 2100 J/kg ∙ K D) 2300 J/kg ∙ K E) 2500 J/kg ∙ K

: C

8) A solid cylindrical bar conducts heat at a rate of 25 W from a hot to a cold reservoir under steady state conditions. If both the length and the diameter of this bar are doubled, the rate at which it will conduct heat between these reservoirs will be A) 200 W B) 100 W C) 50 W D) 25 W E) 12.5 W

: C

8) An aluminum electric tea kettle with a mass of 500 g is heated with a 500-W heating coil. How long will it take to heat up 1.0 kg of water from 18°C to 98°C in the tea kettle? The specific heat of aluminum is 900 J/kg ∙ K and that of water is 4186 J/kg ∙ K. A) 5.0 minutes B) 7.0 minutes C) 12 minutes D) 15 minutes E) 18 minutes

: C

81) A sphere of surface area 1.25 m2 and emissivity 1.0 is at a temperature of 100°C. At what rate does it radiate heat into empty space? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 7.1 W B) 0.71 mW C) 1.4 kW D) 9.9 mW E) 3.7 W

: C

9) An ideal gas is held in a container of volume V at pressure p. The rms speed of a gas molecule under these conditions is v. If now the volume and pressure are changed to 2V and 2p, the rms speed of a molecule will be A) v/2 B) v C) 2v D) 4v E) v/4

: C

9) Two metal rods are to be used to conduct heat from a region at 100°C to a region at 0°C as shown in the figure. The rods can be placed in parallel, as shown on the left, or in series, as on the right. When steady state flow is established, the heat conducted in the series arrangement is A) greater than the heat conducted with the rods in parallel. B) the same as the heat conducted with the rods in parallel. C) less than the heat conducted with the rods in parallel.

: C

90) In an electric furnace used for refining steel, the temperature is monitored by measuring the radiant power emitted through a small hole in the wall of the furnace, of area 0.5 cm2. This hole acts like a perfect blackbody radiator having the same temperature as the interior of the furnace. If the temperature of the furnace (and therefore of the hole) is to be maintained at 1650°C, how much power will the hole radiate? A) 20 W B) 30 W C) 40 W D) 50 W

: C

92) When 0.50 kg of water at 0°C freezes, what is the change in entropy of the water? The latent heat of fusion of water is 33,400 J/kg. A) 0 J/K B) 610 J/K C) -610 J/K D) -17,000 J/K E) 17,000 J/K

: C

23) The coefficient of linear expansion of copper is 17 × 10-6 K-1. A block of copper 30 cm wide, 45 cm long, and 10 cm thick is heated from 0°C to 100°C What is the change in the volume of the block? A) 2.3 × 10-5 m3 B) 4.6 × 10-5 m3 C) 5.2 × 10-5 m3 D) 6.9 × 10-5 m3 E) 14 × 10-5 m3

: D

4) Consider a flat steel plate with a hole through its center as shown in the figure. When the temperature of the plate is increased, the hole will A) expand only if it takes up more than half the plate's surface area. B) contract if it takes up less than half the plate's surface area. C) always contract as the plate expands into it. D) always expand with the plate. E) remain the same size as the plate expands around it.

: D

43) A balloon originally has a volume of 1.0 m3 when the gas in it is at 20°C and under a pressure of 1.0 atm. As it rises in the earth's atmosphere, its volume expands. What will be its new volume if its final temperature and pressure are -40°C and 0.10 atm? A) 2.0 m3 B) 4.0 m3 C) 6.0 m3 D) 8.0 m3

: D

5) A 4.0-kg aluminum block is originally at 10°C. If 160 kJ of heat is added to the block, what is its final temperature? The specific heat capacity of aluminum is 910 J/kg ∙ K. A) 24°C B) 34°C C) 44°C D) 54°C

: D

56) A 40.0-g block of ice at -15.00°C is dropped into a calorimeter (of negligible heat capacity) containing water at 15.00°C. When equilibrium is reached, the final temperature is 8.00°C. How much water did the calorimeter contain initially? The specific heat of ice is 2090 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 302 g B) 345 g C) 405 g D) 546 g E) 634 g

: D

6) Oxygen condenses into a liquid at approximately 90 K. What temperature, in degrees Fahrenheit, does this correspond to? A) -193°F B) -217°F C) -265°F D) -297°F

: D

84) A blacksmith is flattening a steel plate having dimensions 10 cm × 15 cm × 1 mm. He has heated the plate to 900 K. If the emissivity of the plate is 0.75, at what rate does it lose energy by radiation? Ignore any heat exchange with the surroundings. (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 360 W B) 760 W C) 790 W D) 850 W E) 880 W

: D

28) The coefficient of linear expansion of copper is 17 × 10-6 K-1 and that of steel is 12 × 10-6 K-1. At 12°C a steel rod has a diameter of 2.540 cm and a copper pipe has a diameter of 2.536 cm. Which one of the following quantities is closest to the temperature to which the copper pipe must be heated in order for the unheated steel rod to fit snugly in the copper pipe? A) 53°C B) 81°C C) 93°C D) 105°C E) 143°C

: D

3) The temperature changes from 35°F during the night to 75°F during the day. What is the temperature change on the Celsius scale? A) 72 C° B) 40 C° C) 32 C° D) 22 C°

: D

4) Which one of the following quantities is the smallest unit of heat energy? A) calorie B) kilocalorie C) Btu D) joule

: D

41) A car starts out when the air temperature is 288 K and the absolute (total) air pressure in the tires is 500 kPa. After driving a while, the temperature of the air in the tires increases to 298 K. What is the pressure in the tires at that point, assuming their volume does not change? A) 129 kPa B) 483 kPa C) 507 kPa D) 517 kPa E) 532 kPa

: D

44) A camper is about to drink his morning coffee. He pours 400 grams of coffee, initially at 75°C into a 250-g aluminum cup, initially at 16°C. What is the equilibrium temperature of the coffee-cup system, assuming no heat is lost to the surroundings? The specific heat of aluminum is 900 J/kg ∙ K, and the specific heat of coffee is essentially the same as that of water, which is 4186 J/kg ∙ K. A) 45°C B) 62°C C) 65°C D) 68°C E) 71°C

: D

54) A 35-g block of ice at -14°C is dropped into a calorimeter (of negligible heat capacity) containing 400 g of water at 0°C. When the system reaches equilibrium, how much ice is left in the calorimeter? The specific heat of ice is 2090 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 32 g B) 33 g C) 35 g D) 38 g E) 41 g

: D

58) An 920-g piece of iron at 100°C is dropped into a calorimeter of negligible heat capacity containing 50 g of ice at 0°C and 92 g of water, also at 0°C. What is the final temperature of the system? The specific heat of iron is 448 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 0°C B) 11°C C) 14°C D) 24°C E) 32°C

: D

17) A fixed container holds oxygen and helium gases at the same temperature. Which of the following statements are correct? (There could be more than one correct choice.) A) The oxygen molecules have the greater average kinetic energy. B) The helium molecules have the greater average kinetic energy. C) The oxygen molecules have the greater speed. D) The helium molecules have the greater speed. E) The helium molecules have the same average kinetic as the oxygen molecules.

: D, E

26) The coefficient of linear expansion of aluminum is 24.0 × 10-6 K-1, and the density of aluminum at 0°C is 2.70 × 103 kg/m3. What is the density of aluminum at 300°C? A) 3.93 × 103 kg/m3 B) 2.73 × 103 kg/m3 C) 2.70 × 103 kg/m3 D) 2.67 × 103 kg/m3 E) 2.64 × 103 kg/m3

: E

47) A 20.0-L pressure vessel holds 2.00 mol of oxygen at 30°C. What is the pressure inside the vessel? (R = 8.31 J/mol ∙ K) A) 101 Pa B) 101 kPa C) 1.01 MPa D) 2.52 MPa E) 252 kPa

: E

80) In an experiment to measure the thermal conductivity of a certain material, a slab of material 10.0 mm thick separates a steam chamber from a block of ice with a square cross-section with dimensions 8.00 cm × 8.00 cm. After 5.00 min of running the experiment, 64.0 g of ice have melted. What is the thermal conductivity of this material? The latent heat of fusion of water is 33.5 × 104 J/kg, the latent heat of vaporization of water is 2.256 × 106 J/kg, and both the ice and water are under 1.00 atm of pressure. A) 0.130 W/m ∙ K B) 0.250 W/m ∙ K C) 0.440 W/m ∙ K D) 0.620 W/m ∙ K E) 1.12 W/m ∙ K

: E

15) If the absolute temperature of an object is tripled, the thermal power radiated by this object (assuming that its emissivity and size are not affected by the temperature change) will A) increase by a factor of 3. B) increase by a factor of 9. C) increase by a factor of 18. D) increase by a factor of 27. E) increase by a factor of 81.

: E

2) A person running in place on an exercise machine for 10 min uses up 17 kcal (food calories). Another person exercises by repeatedly lifting two 2.5-kg weights a distance of 50 cm. How many repetitions of this exercise are equivalent to 10 minutes of running in place? Assume that the person uses negligible energy in letting down the weights after each lift. (1 cal = 4.186 J) A) 730 B) 1450 C) 1500 D) 2200 E) 2900

: E

24) If you add 1.33 MJ of heat to 500 g of water at 50°C in a sealed container, what is the final temperature of the steam? The latent heat of vaporization of water is 22.6 × 105 J/kg, the specific heat of steam is 2010 J/kg ∙ K, and the specific heat of water is 4186 J/kg ∙ K. A) 100°C B) 112°C C) 123°C D) 147°C E) 195°C

: E

4) How much heat is required to raise the temperature of a 225-g lead ball from 15.0°C to 25.0°C? The specific heat of lead is 128 J/kg ∙ K. A) 725 J B) 576 J C) 145 J D) 217 J E) 288 J

: E

5) Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are given the same amount of heat. If the temperature of Object 1 changes by an amount ΔT, the change in temperature of Object 2 will be A) ΔT. B) ΔT. C) ΔT. D) 6ΔT. E) 12ΔT.

: E

6) Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are heated from the same initial temperature, T0, to the same final temperature Tf. During this process, if Object 1 absorbs heat Q, the amount of heat absorbed by Object 2 will be A) 12Q. B) 6Q. C) Q. D) Q. E) Q.

: E

67) The rms speed of a certain sample of carbon dioxide molecules, with a molecular weight of 44.0 g/mole, is 396 m/s. What is the rms speed of water vapor molecules, with a molecular weight of 18.0 g/mol, at the same temperature as the carbon dioxide? A) 253 m/s B) 387 m/s C) 421 m/s D) 506 m/s E) 619 m/s

: E

71) A glass tea kettle containing 500 g of water is on the stove. The portion of the tea kettle that is in contact with the heating element has an area of 0.090 m2 and is 1.5 mm thick. At a certain moment, the temperature of the water is 75°C, and it is rising at the rate of 3 C° per minute. What is the temperature of the outside surface of the bottom of the tea kettle? Neglect the heat capacity of the kettle, and assume that the inner surface of the kettle is at the same temperature as the water inside. The thermal conductivity of glass is 0.840 W/m ∙ K and the specific heat of water is 4186 J/kg ∙ K. A) 39°C B) 92°C C) 120°C D) 86°C E) 77°C

: E

14) A monatomic ideal gas undergoes an isothermal expansion at 300 K, as the volume increased from to The final pressure is What is the change in the internal (thermal) energy of the gas during this process? (R = 8.31 J/mol ∙ K) A) 0.0 kJ B) 3.6 kJ C) 7.2 kJ D) -3.6 kJ E) -7.2 kJ

: A

3) The figure shows a pV diagram for 2.9 g of ideal oxygen gas O2 in a sealed container. The temperature of state 1 is 76° C, the atomic mass of the oxygen atom is 16 g/mol, and R = 8.31 J/mol ∙ K. What are the temperatures T3 and T4? A) -11° C and 510° C B) 57° C and 170° C C) 260° C and 790° C D) 38° C and 110° C

: A

5) The figure shows a pV diagram for 0.0061 mol of ideal gas that undergoes the process 1 → 2 → 3. What is the pressure p2? (R = 8.31 J/mol ∙ K) A) 4.9 atm B) 4.9 × 105 atm C) 15 atm D) 1.5 × 106 atm

: A

75) An ideal reversible heat pump is taking heat from the outside air at -10.0°C and discharging it into the house at 18.0°C. What is the coefficient of performance of this heat pump? A) 10.4 B) 9.44 C) 0.644 D) 0.533 E) 0.0962

: A

79) An ideal Carnot engine is operated as an air conditioner to cool a house in the summer. The air conditioner removes of heat per second from the house, and maintains the inside temperature at while the outside temperature is The power required to run the air conditioner under these operating conditions is closest to A) 3600 W. B) 4400 W. C) 5100 W. D) 5800 W. E) 6600 W.

: A

8) A compression at a constant pressure of 200 kPa is performed on 8.00 moles of an ideal monatomic gas. The compression reduces the volume of the gas from to How much work was done by the gas during this process? A) -16 kJ B) 16 kJ C) -40 kJ D) 40 kJ E) 0 kJ

: A

12) A gas expands from an initial volume of 30.0 L to a final volume of 65.0 L at a constant pressure of 110 kPa. How much work is done by the gas during this expansion? A) 3.85 kJ B) 10.4 kJ C) 3850 kJ D) 10.4 MJ E) 3.85 MJ

: A

2) An ideal gas is compressed isothermally to one-third of its initial volume. The resulting pressure will be A) three times as large as the initial value. B) less than three times as large as the initial value. C) more than three times as large as the initial value. D) equal to the initial value. E) impossible to predict on the basis of this data.

: A

21) In an isochoric process, the internal (thermal) energy of a gas decreases by 50 J. How much work is done by the gas during this process? A) 0 J B) 50 J C) -50 J D) 25 J E) -25 J

: A

23) A fixed amount of an ideal monatomic gas is maintained at constant volume as it is cooled by 50 K. This feat is accomplished by removing 400 J of energy from the gas. How much work is done by the gas during this process? A) 0 J B) 400 J C) -400 J D) -200 J E) 200 J

: A

25) The gas in a perfectly insulated but flexible container does work at a rate of At what rate is the internal (thermal) energy of the gas changing? A) -13 W B) 13 W C) 0 W D) 6.5 W

: A

26) A fluid in an insulated, flexible bottle is heated by a high resistance wire and expands. If of heat is applied to the system and it does of work, how much does the internal (thermal) energy of the fluid change? A) 4.0 kJ B) 14 kJ C) -4.0 kJ D) 45 kJ

: A

29) An ideal gas undergoes the process a→b→c→a shown in the pV diagram. The heat gained by the gas in process a→b is 546 J, while in process the gas loses 62.0 J of heat. In process a→b the gas performs of work, while in process c→a 223 J of work is done on the gas. How much heat is gained by the gas in process c→a? A) -397 J B) -62 J C) 223 J D) 18 J E) -236 J

: A

32) A heat engine receives 7000 J of heat and loses 3000 J in each cycle. What is the efficiency of this engine? A) 57% B) 30% C) 70% D) 43%

: A

42) The figure shows a pV diagram for a cycle of a heat engine for which QH = 59 J. What is the thermal efficiency of the engine? A) 17% B) 34% C) 8.5% D) 14%

: A

57) An ideal Carnot engine operates between a high temperature reservoir at and a river with water at If it absorbs of heat each cycle, how much work per cycle does it perform? A) 1642 J B) 2358 J C) 1483 J D) 2517 J

: A

7) The temperature of an ideal gas in a sealed rigid 0.20- container is reduced from 360 K to and the final pressure of the gas is How much work is done by the gas during this process? (R = 8.31 J/mol ∙ K) A) 0 kJ B) -9.0 kJ C) -12 kJ D) 9.0 kJ E) 12 kJ

: A

78) A Carnot air conditioner has a coefficient of performance of 17.0 and removes 72.0 MJ of heat from the interior of a house every hour. How much power does it consume? A) 1180 W B) 1320 W C) 520 kW D) 3.14 MW E) 1.25 MW

: A

9) An expansion process on an ideal diatomic ideal gas has a linear path between the initial and final coordinates on a pV diagram. The coordinates of the initial state are: the pressure is 300 kPa, the volume is and the temperature is The final pressure is and the final temperature is How much work is done by the gas during this process? (R = 8.31 J/mol ∙ K) A) 13,000 J B) 6300 J C) 9400 J D) 16,000 J E) 19,000 J

: A

10) A 10-L flask and a 1-L flask each contain two moles of ideal diatomic gas (but not the same gas) at 25°C. Which of the following statements about these gases must be true? (There could be more than one correct choice.) A) The internal (thermal) energy of the gas in both flasks is the same. B) The internal (thermal) energy of the gas in the larger flask is greater than the internal (thermal) energy of the gas in the smaller flask. C) The internal (thermal) energy of the gas in the smaller flask is greater than the internal (thermal) energy of the gas in the larger flask. D) The molecules in the larger flask have the same root-mean-square speed as those in the smaller flask. E) The molecules in the smaller flask have the same average kinetic energy per molecule as those in the larger flask.

: A, E

11) An ideal gas undergoes the process a→b→c→a shown in the pV diagram. In this figure, Pa = Pc = 3.60 × 105 Pa, Vb = Vc = 68.00 L, Va = 35 L, and Pb = 5.60 × 105 Pa. How much work is done by the system in this process? A) 2300 J B) 3300 J C) 2800 J D) 3800 J E) 3000 J

: B

28) An athlete doing push-ups performs 650 kJ of work and loses 425 kJ of heat. What is the change in the internal (thermal) energy of the athlete? A) -225 kJ B) -1075 kJ C) 1075 kJ D) 225 kJ E) 276 kJ

: B

4) In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume. Which one of the following statements about the gas is correct? A) The gas must absorb heat from its surroundings. B) The gas must release heat to its surroundings. C) The pressure of the gas also stays constant. D) The process is adiabatic. E) It is impossible to predict on the basis of this data.

: B

76) An ideal Carnot air conditioner operates between an indoor temperature of 20°C and an outdoor temperature of 39°C. How much energy does it use to remove 2000 J of heat from the interior of the house? A) 105 J B) 130 J C) 780 J D) 520 J E) 340 J

: B

30) An ideal gas undergoes the process a→b→c→a shown in the pV diagram. In the figure, Pa = Pc = 240 kPa, Vb = Vc = 40 L, Va = 15 L, and Pb = 400 kPa. How much heat is gained by the gas in this a→b→c→a process? A) 1000 J B) 1500 J C) 2000 J D) 2500 J E) 3000 J

: C

12) A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle, as shown in the pV diagram in the figure. If the process is carried out in a clockwise sense around the enclosed area, as shown on the figure, then the change of internal energy over the full cycle A) is positive. B) is negative. C) is zero. D) cannot be determined from the information given.

: C

19) In an adiabatic compression, 200 J of work is done on a gas. What is the change in internal (thermal) energy of the gas during this compression? A) 0 J B) 100 J C) 200 J D) -200 J

: C

20) An ideal gas undergoes an adiabatic process while doing 25 J of work. What is the change in the internal (thermal) energy of the gas? A) 0 J B) 25 J C) -25 J D) 50 J E) -50 J

: C

20) Which of the following is a false statement? A) Entropy is a quantitative measure of disorder. B) The total entropy change in one cycle of a Carnot engine is zero. C) The entropy of an isolated system must be conserved (it remains constant). D) Entropy can be measured in units of J/K.

: C

21) An ideal gas undergoes an isothermal expansion. During this process, its entropy A) decreases. B) remains unchanged. C) increases. D) cannot be predicted from the data given.

: C

22) During an isochoric process, the internal (thermal) energy of a gas decreases by 50 J. How much heat is added to the gas during this process? A) 0 J B) 50 J C) -50 J D) 25 J E) -25 J

: C

24) An external heat source supplies heat to a system at a rate of 187 W as the system does work at a rate of 131 W. At what rate is the internal (thermal) energy of the system changing? A) -56 W B) 320 W C) 56 W D) 190 W E) -320 W

: C

52) For a certain ideal Carnot engine, the hot reservoir is 35 C° higher than the cold reservoir. If this engine is to have an efficiency of 20%, what must be the temperature of the hot reservoir? A) 70.0 K B) 140 K C) 175 K D) 210 K E) 245 K

: C

70) During each cycle of operation, a refrigerator absorbs 230 J of heat from the freezer and expels 356 J of heat to the room. How much work input is required in each cycle? A) 712 J B) 586 J C) 460 J D) 126 J

: D

13) A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle, as shown in the pV diagram in the figure. If the process is carried out in a clockwise sense around the enclosed area, as shown on the figure, then the magnitude of the enclosed area represents A) the heat that flows out of the gas. B) the work done on the gas. C) the heat added to the gas. D) the work done by the gas.

: D

49) A heat engine having the maximum possible efficiency has an efficiency of 35.0% when operating between two heat reservoirs. If the temperature of the hot reservoir is 700 K, what is the temperature of the cold reservoir? A) 200 K B) 245 K C) 350 K D) 455 K E) 600 K

: D

74) An air conditioner with a coefficient of performance of 3.50 uses 30.0 kW of power to operate. What power is it discharging to the outdoors? A) 30.0 kW B) 75.0 kW C) 105 kW D) 135 kW E) 210 kW

: D

15) Which one of the following is a true statement? A) The second law of thermodynamics is a consequence of the first law of thermodynamics. B) It is possible for heat to flow spontaneously from a hot body to a cold one or from a cold one to a hot one, depending on whether or not the process is reversible or irreversible. C) It is not possible to convert work entirely into heat. D) It is impossible to transfer heat from a cooler to a hotter body. E) All of these statements are false.

: E

19) An important feature of the Carnot cycle is that A) its efficiency can be 100%. B) its efficiency depends only on the absolute temperature of the hot reservoir used. C) its efficiency is determined by the temperatures of the hot and cold reservoirs between which it works and by the properties of the working substance used, and on nothing else. D) it is an example of an irreversible process that can be analyzed exactly without approximations. E) no engine can be more efficient than a Carnot engine operating between the same two temperatures.

: E

31) A 40.0-L container is divided into two equal parts by a rubber membrane. One half of the container has 1.50 moles of an ideal monatomic gas at 250 K, and the other half is a vacuum. The container is well insulated, so there is no exchange of heat with the surroundings. The membrane breaks, and eventually the gas reaches a new equilibrium condition occupying the entire volume. What is the final temperature of the gas? A) 100 K B) 125 K C) 157 K D) 180 K E) 250 K

: E

77) During each cycle, the compressor in a certain ideal Carnot refrigerator performs 480 J of work to remove 150 J of heat from the interior of the refrigerator. How much heat do the coils behind the refrigerator discharge into the kitchen each cycle? A) 110 J B) 150 J C) 330 J D) 480 J E) 630 J

: E

22) When water at 0°C freezes, the entropy of the water A) increases. B) decreases. C) remains constant. D) could either increase or decrease it depends on other factors

:B

Radiation

Energy that is radiated or transmitted in the form of rays or waves or particles.

2nd law of thermodynamics (heat)

Heat can flow spontaneously from a hot object to a cold object; it will not flow spontaneously from a cold object to a hot object.

Zeroth Law of Thermodynamics

Two objects placed in thermal contact will eventually come to the same temperature. if two objects are each in equilibrium with a third object, they are also in thermal equilibrium with each other.

Isobaric Process

constant pressure, Q= U + PV

isothermal process

constant temperature, T=0 makes U=0, so Q=W

isovolumetric process

constant volume (V=0) makes W=0 so Q= U

latent heat

energy required to change the phase of a substance