# Quiz 18: Heat and the First Law of Thermodynamics

Physics & Astronomy

Q 1Q 1

Two liquids, A and B, are mixed together, and the resulting temperature is 22C. If liquid A has mass m and was initially at temperature 35C, and liquid B has mass 3m and was initially at temperature 11C, calculate the ratio of the specific heats of A divided by B.
A) 0.85
B) 2.5
C) 1.2
D) 0.45
E) 0.94

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Multiple Choice

B

Q 2Q 2

Two liquids, A and B, are mixed together. Liquid A has mass m and was initially at temperature 40C, and liquid B has mass 2m and was initially at temperature 5C. The specific heat of liquid A is 1.5 times that of liquid B.
Calculate the final temperature of the mixture.
A) 33.5C
B) 14.3C
C) 17.0C
D) 20.0C
E) 25.7C

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Multiple Choice

D

Q 3Q 3

The quantity of heat absorbed by a body is determined from the formula Q = cm(T

_{f}- T_{i}). A certain metal has a specific heat c = 0.21 cal/g Cº and a mass m = 25.6 g. The initial temperature is T_{i}= 34.6ºC, and the final temperature T_{f}= 54.6ºC. The quantity of heat absorbed is A) +23 cal B) +0.23 cal C) +14 cal D) +110 cal E) +207 calFree

Multiple Choice

D

Q 4Q 4

Aluminum has a specific heat more than twice that of copper. Identical masses of aluminum and copper, both at 0ºC, are dropped together into a can of hot water. When the system has come to equilibrium,
A) the aluminum is at a higher temperature than the copper.
B) the copper is at a higher temperature than the aluminum.
C) the aluminum and copper are at the same temperature.
D) the difference in temperature between the aluminum and the copper depends on the amount of water in the can.
E) the difference in temperature between the aluminum and the copper depends on the initial temperature of the water in the can.

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Multiple Choice

Q 5Q 5

Which of the following statements about heat and work is the proper usage of the terms?
A) a system has 50 J of heat
B) 50 J of heat is transferred from the environment to the system
C) a system has 50 J of work
D) a system does 50 J of work on the environment
E) (B) and (D)

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Multiple Choice

Q 6Q 6

A system has a heat capacity of 100 J. This means
A) it is possible to extract the 100 J of heat and convert it to work.
B) it is possible to transfer the 100 J of heat to the environment.
C) some of the heat capacity can be converted to work.
D) some of the heat capacity can be transferred to another system if there is a temperature difference.
E) (C) and (D)

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Multiple Choice

Q 7Q 7

The specific heat of a substance is a measure of
A) energy needed to change the kinetic energies of atoms and/or molecules and/or electrons by a temperature increment.
B) total energy in the substance for a given temperature change.
C) energy needed to vaporize/liquefy the substance.
D) energy needed to liquefy/solidify the substance.
E) none of the above

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Multiple Choice

Q 8Q 8

A lake with 8.0 10

^{9 }kg of water, which has a specific heat of 4180 J/kg · Cº, warms from 10 to 15ºC. The amount of heat transferred to the lake is A) 2.5 10^{3}J B) 1.7 10^{14}J C) 4.0 10^{15}J D) 1.7 10^{16}J E) 2.8 10^{16}JFree

Multiple Choice

Q 9Q 9

Body A has twice the mass and three times the specific heat of body B. They are supplied with equal amounts of heat. Body A experiences a temperature change T. What change in temperature is experienced by body B?
A) T
B) 3T/2
C) 2T/3
D) 6T
E) T/2

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Multiple Choice

Q 10Q 10

To raise the temperature of a 2.0-kg piece of metal from 20º to 100ºC, 61.8 kJ of heat is added. What is the specific heat of this metal?
A) 0.39 kJ/kg · K
B) 0.31 kJ/kg · K
C) 1.6 kJ/kg · K
D) 1.2 kJ/kg · K
E) 0.77 kJ/kg · K

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Multiple Choice

Q 11Q 11

A 250-g piece of lead is heated to 100ºC and is then placed in a 400-g copper container holding 500 g of water. The specific heat of copper is c = 0.386 kJ/kg · K. The container and the water had an initial temperature of 18.0ºC. When thermal equilibrium is reached, the final temperature of the system is 19.15ºC. If no heat has been lost from the system, what is the specific heat of the lead? (the specific heat of water is 4.180 kJ/kg · K)
A) 0.119 kJ/kg · K
B) 0.128 kJ/kg · K
C) 0.110 kJ/kg · K
D) 0.0866 kJ/kg · K
E) 0.0372 kJ/kg · K

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Multiple Choice

Q 12Q 12

Use the following to answer questions :
-Heat is added to a substance at a constant rate. The substance starts as a solid and is melted; the liquid is heated and vaporized; finally, the vapor is heated. This process is shown in the graph. The specific heat of the solid can be found by
A) multiplying the length of B (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
B) multiplying the length of D (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
C) dividing the rate at which heat is added by the product of the slope of A and the mass of the substance.
D) dividing the rate at which heat is added by the product of the slope of C and the mass of the substance.
E) dividing the rate at which heat is added by the product of the slope of E and the mass of the substance.

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Multiple Choice

Q 13Q 13

Use the following to answer questions :
-Heat is added to a substance at a constant rate. The substance starts as a solid and is melted; the liquid is heated and vaporized; finally, the vapor is heated. This process is shown in the graph. The specific heat of the liquid can be found by
A) multiplying the length of B (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
B) multiplying the length of D (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
C) dividing the rate at which heat is added by the product of the slope of A and the mass of the substance.
D) dividing the rate at which heat is added by the product of the slope of C and the mass of the substance.
E) dividing the rate at which heat is added by the product of the slope of E and the mass of the substance.

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Multiple Choice

Q 14Q 14

Use the following to answer questions :
-Heat is added to a substance at a constant rate. The substance starts as a solid and is melted; the liquid is heated and vaporized; finally, the vapor is heated at constant volume. This process is shown in the graph. The specific heat at constant volume of the vapor can be found by
A) multiplying the length of B (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
B) multiplying the length of D (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
C) dividing the rate at which heat is added by the product of the slope of A and the mass of the substance.
D) dividing the rate at which heat is added by the product of the slope of C and the mass of the substance.
E) dividing the rate at which heat is added by the product of the slope of E and the mass of the substance.

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Multiple Choice

Q 15Q 15

At liquid

^{4}He temperatures (< 4.2 K), the molar heat capacity heat of most insulators goes as C = AT^{3}, where A is a constant and T is in kelvins. The ratio of the heat required to raise the temperature from 2 K to 3K and from 1 K to 2K is A) 3/2 B) 19/7 C) 65/15 D) 1/2 E) 1/1Free

Multiple Choice

Q 16Q 16

For most metals, the heat capacity goes as C = T + AT

^{3}at low temperatures (~ 100 K), whereas insulators only has the T^{3}term. Both and A are constants. The two terms in the expression for C suggests A) there are at least two degrees of freedom in metals. B) there are two independent mechanisms for heat to be absorbed or released in metals. C) that there are two kinds of heat that are absorbed by metals. D) that thermal energy is transferred to metals differently than insulators. E) nothing. It just happens that way.Free

Multiple Choice

Q 17Q 17

A 1.0-kg piece of marble at 100ºC is dropped into 2.5 kg of water at 1.0ºC and the resulting temperature is 7.0ºC. The specific heat of the marble is approximately
A) 0.16 kcal/kg · Cº
B) 0.75 kcal/kg · Cº
C) 0.61 kcal/kg · Cº
D) 0.30 kcal/kg · Cº
E) 0.26 kcal/kg · Cº

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Multiple Choice

Q 18Q 18

Glass beads of mass 100 g and specific heat 0.20 cal/g · Cº are heated to 90ºC and placed in a 300-g glass beaker containing 200 g of water at 20ºC. When equilibrium is reached, the temperature is approximately
A) 23ºC
B) 25ºC
C) 27ºC
D) 32ºC
E) 39ºC

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Multiple Choice

Q 19Q 19

A 2.0-kg mass of iron (specific heat = 0.12 kcal/kg · Cº) at a temperature of 430ºC is dropped into 48 kg of water. The water is initially at a temperature of 10ºC. With no heat losses to the surroundings, the equilibrium temperature of the iron and water is approximately
A) 12ºC
B) 18ºC
C) 19ºC
D) 30ºC
E) 33ºC

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Multiple Choice

Q 20Q 20

The molar specific heat of copper is 24.5 J/(molK). The amount of heat needed to raise 126 g of copper by 2C is
A) 24.5 J
B) 49 J
C) 12.3 J
D) 98 J
E) 147 J

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Multiple Choice

Q 21Q 21

A small lake has a surface area of 10000 m

^{2}. Assuming that the average depth of the lake is 2 m, how much heat is released when the average temperature of the water in the lake drops by 1C? A) 8.36 10^{1}^{0}J B) 8.36 10^{7}J C) 2.0 10^{8}J D) 2.0 10^{11}J E) 8.36 10^{3}JFree

Multiple Choice

Q 22Q 22

The temperature of water in the Gulf of Mexico can rise by about 20F with the onset of the summer. However, the most significant temperature rise is confined to the top 2-3 meters of water. Assuming that it takes 45 days for the temperature to increase by 20F, what is the average energy absorbed per day by water in a volume measuring 1 m 1 m 2.5 m?
A) 1.16 10

^{9}J B) 2.58 10^{6}J C) 4.64 10^{7}J D) 2.09 10^{9}J E) 2.5 10^{5}JFree

Multiple Choice

Q 23Q 23

The specific heat of a gas is
A) the same for all gases.
B) directly proportional to the absolute temperature.
C) independent of constraints imposed on it while heating.
D) a negligible quantity.
E) greater at constant pressure than at constant volume.

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Multiple Choice

Q 24Q 24

The specific heat of a gas at constant pressure is
A) directly proportional to the pressure.
B) inversely proportional to the pressure.
C) always greater than the specific heat at constant volume.
D) always less than the specific heat at constant volume.
E) independent of the kind of gas.

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Multiple Choice

Q 25Q 25

If the heat given off by 300 g of an alloy as it cools through 50 Cº is sufficient to raise the temperature of 300 g of water from 30º to 40ºC, the specific heat of the alloy must be approximately
A) 0.015 cal/g · Cº
B) 0.10 cal/g · Cº
C) 0.15 cal/g · Cº
D) 0.20 cal/g · Cº
E) 0.50 cal/g · Cº

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Multiple Choice

Q 26Q 26

A 2.0-kg mass of iron (specific heat = 0.12 kcal/kgC) at a temperature of 430C is dropped into 0.4 kg of ice and 0.4 kg of water both at 0C. With no heat losses to the surroundings, the equilibrium temperature of the mixture is approximately
A) 0C
B) 100C
C) 23C
D) 69C
E) 87C

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Multiple Choice

Q 27Q 27

A 4-kg mass of metal of unknown specific heat at a temperature of 600C is dropped into 0.5 kg of ice and 0.5 kg of water both at 0C. With no heat losses to the surroundings, the equilibrium temperature of the mixture is 85C. Calculate the specific heat of the metal.
A) 0.04 kcal/kgC
B) 0.06 kcal/kgC
C) 0.08 kcal/kgC
D) 1.6 kcal/kgC
E) 1.2 kcal/kgC

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Multiple Choice

Q 28Q 28

A 3-kg mass of metal of specific heat = 0.1 kcal/kgC at a temperature of 600C is dropped into 1.0 kg water at 20C. With no heat losses to the surroundings, determine the equilibrium temperature of the mixture, and if it is 100C, calculate what mass of water is turned into steam at this temperature.
A) 100C and 110 g of steam
B) 100C and 150 g of steam
C) 100C and 130 g of steam
D) 100C and 70 g of steam
E) The equilibrium temperature is not 100C.

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Multiple Choice

Q 29Q 29

When a substance changes phase, from solid to liquid or liquid to vapor and vice versa, there is no change in temperature, even though heat is being added or removed. Why is there no change in temperature?
A) During a phase change, energy is used to break/establish the intermolecular bonds rather than stored as kinetic energy of the molecules.
B) During a phase change, temperature is not well defined since there are two phases involved.
C) During a phase change, energy is needed to overcome the gravitational pull.
D) During a phase change, the temperature measured is the last temperature of the measuring device.
E) none of the above

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Multiple Choice

Q 30Q 30

Some water is poured into some ice. What will happen to the water? Assume no heat loss to the surrounding.
A) The water stays as water.
B) Some of the water freezes.
C) All the water freezes.
D) Unable to tell what will happen.
E) It depends on how fast you pour the water into the ice.

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Multiple Choice

Q 31Q 31

On a hot summer day, water collects on the outside of a glass of ice lemonade. The water comes from
A) inside the glass since glass is porous.
B) the condensation of the water vapor due the fact that the glass is much colder than the air.
C) the straw you use to drink your lemonade.
D) the mixture of water and lemonade.
E) It is one of the mysteries of life.

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Multiple Choice

Q 32Q 32

A container contains a 200 mL of 100% proof alcohol (i.e., it has 50% ethyl alcohol and 50% water by volume) at 20C. How much heat is needed to bring the mixture to the boiling point of the alcohol? (assume that the specific heat in the 100% proof can be treated as due to the alcohol and water separately, and the density, boiling point and specific heat of alcohol are 0.81 g/cm

^{3}, 78C, and 2.4 J/(gC), respectively) A) 32650 J B) 35525 J C) 11136 J D) 17400 J E) 48557 JFree

Multiple Choice

Q 33Q 33

A container contains a 200 mL of 100% proof alcohol (i.e., it has 50% ethyl alcohol and 50% water by volume) at the boiling point of the alcohol. How long does it take to distill (boil) all the alcohol if heat is supplied at a rate of 100 W? (The density and latent heat of vaporization of ethyl alcohol are 0.81 g/cm

^{3}, and 879 kJ/kg.) A) 712 s B) 1110 s C) 450 s D) 1450 s E) 950 sFree

Multiple Choice

Q 34Q 34

If 100 g of steam at 100C were mixed with 10 kg of ice at 100C, find the final temperature of the mixture assuming no heat losses to the surroundings.
A) 85C
B) 65C
C) 0C
D) 15C
E) 43C

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Multiple Choice

Q 35Q 35

If the heat capacities of both ice and steam are 0.5 cal/g · Cº, the quantity of heat required to change 1 g of ice at -10ºC to steam at 120ºC is approximately
A) 750 cal
B) 735 cal
C) 630 cal
D) 620 cal
E) 555 cal

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Multiple Choice

Q 36Q 36

A group of explorers in the Antarctic can obtain the water they need only by melting snow. How much heat does it take for them to make a cup of coffee (100 g water at 100ºC)? Assume that the snow has an initial temperature of -40ºC; that the latent heats of fusion and vaporization of water are, respectively, 333.5 kJ/kg and 2257 kJ/kg; and that the specific heats of ice (snow) and water are, respectively, 2.05 kJ/kg · K and 4.18 kJ/kg · K.
A) 33 kJ
B) 50 kJ
C) 75 kJ
D) 83 kJ
E) 310 kJ

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Multiple Choice

Q 37Q 37

You add 50 g of ice cubes to 125 g of water that is initially at 20ºC in a calorimeter of negligible heat capacity. When the system has reached equilibrium, how much of the ice remains?
A) 31 g
B) 48 g
C) 19 g
D) 47 g
E) all of the ice melts

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Multiple Choice

Q 38Q 38

Use the following to answer questions :
-Heat is added to a substance at a constant rate. The substance starts as a solid and is melted; the liquid is heated and vaporized; finally, the vapor is heated. This process is shown in the graph. Which of the following statements is correct?
A) The latent heat of fusion is greater than the latent heat of vaporization.
B) The latent heat of vaporization is greater than the latent heat of fusion.
C) The latent heat of vaporization is equal to the latent heat of fusion.
D) The mass of the substance must be known before any statements about the latent heats can be made.
E) The relative sizes of the latent heats depend on the rate at which the heat is added.

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Multiple Choice

Q 39Q 39

Use the following to answer questions :
-Heat is added to a substance at a constant rate. The substance starts as a solid and is melted; the liquid is heated and vaporized; finally, the vapor is heated. This process is shown in the graph. The latent heat of fusion can be found by
A) multiplying the length of B (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
B) multiplying the length of D (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
C) multiplying the slope of A by the rate at which heat is added, and dividing by the mass of the substance.
D) multiplying the slope of C by the rate at which heat is added, and dividing by the mass of the substance.
E) multiplying the slope of E by the rate at which heat is added, and dividing by the mass of the substance.

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Multiple Choice

Q 40Q 40

Use the following to answer questions :
-Heat is added to a substance at a constant rate. The substance starts as a solid and is melted; the liquid is heated and vaporized; finally, the vapor is heated. This process is shown in the graph. The latent heat of vaporization can be found by
A) multiplying the length of B (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
B) multiplying the length of D (in seconds) by the rate at which heat is added, and dividing by the mass of the substance.
C) multiplying the slope of A by the rate at which heat is added, and dividing by the mass of the substance.
D) multiplying the slope of C by the rate at which heat is added, and dividing by the mass of the substance.
E) multiplying the slope of E by the rate at which heat is added, and dividing by the mass of the substance.

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Multiple Choice

Q 41Q 41

When a substance goes directly from a solid state to a gaseous form, the process is known as
A) vaporization.
B) evaporization.
C) condensation.
D) sublimation.
E) deposition.

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Multiple Choice

Q 42Q 42

A small water reactor recently installed at Podunk College is operating at the boiling point of water due to the malfunctioning of the cooling system. The operators observe that the water boils away at the rate of 10 L/min. If they assume that all of the reactor energy is absorbed in the water, the power developed by the reactor is approximately
A) hp
B) 378 W
C) 56 kW
D) 378 kW
E) 22.7 MW

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Multiple Choice

Q 43Q 43

The temperature of a solid during conversion to a liquid and then to a vapor by the addition of heat is best represented by curve
A) 1
B) 2
C) 3
D) 4
E) 5

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Multiple Choice

Q 44Q 44

Use the following to answer questions :
-The graph shows the temperature of a 1.0-g sample of material as heat is added to it. The material is initially a solid at 10ºC. The pressure remains constant, and there is no chemical change. The melting point temperature is
A) 10ºC
B) 100ºC
C) 60ºC
D) 73ºC
E) None of these is correct.

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Multiple Choice

Q 45Q 45

Use the following to answer questions :
-The graph shows the temperature of a 1.0-g sample of material as heat is added to it. The material is initially a solid at 10ºC. The pressure remains constant, and there is no chemical change. The heat of fusion of the material is
A) 10 cal/g
B) 50 cal/g
C) 30 cal/g
D) 90 cal/g
E) None of these is correct.

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Multiple Choice

Q 46Q 46

Use the following to answer questions :
-The graph shows the temperature of a 1.0-g sample of material as heat is added to it. The material is initially a solid at 10ºC. The pressure remains constant, and there is no chemical change. The specific heat of the solid phase is
A) 0.6 cal/g · Cº
B) 0.25 cal/g · Cº
C) 1.6 cal/g · Cº
D) 1.7 cal/g · Cº
E) None of these is correct.

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Multiple Choice

Q 47Q 47

Use the following to answer questions :
-The graph shows the temperature of a 1.0-g sample of material as heat is added to it. The material is initially a solid at 10ºC. The pressure remains constant, and there is no chemical change. The specific heat of the liquid phase is
A) 0.84 cal/g · Cº
B) 0.25 cal/g · Cº
C) 1.6 cal/g · Cº
D) 1.7 cal/g · Cº
E) None of these is correct.

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Multiple Choice

Q 48Q 48

A 6.0-g lead bullet traveling at 300 m/s penetrates a wooden block and stops. If 50 percent of the initial kinetic energy of the bullet is converted into thermal energy in the bullet, by how much does the bullet's temperature increase? (The specific heat of lead is 128 J/kg · K.)
A) 0.17º C
B) 1.8 10

^{2}ºC C) 17 ºC D) 3.5 10^{2}ºC E) 35 ºCFree

Multiple Choice

Q 49Q 49

A system absorbs heat Q and has an equal amount of positive work done on it. What is the change in the internal energy of the system?
A) Q
B) 2Q
C) -2Q
D) zero
E) Q/2

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Multiple Choice

Q 50Q 50

Besides Joule's classic experiment, another way of demonstrating the equivalence between mechanical energy and heat is the following: Put some lead shot into a glass tube, seal both ends of the tube, invert the tube quickly several times, and measure the temperature of the shot. If you assume that all the mechanical energy is converted into heat in the lead shot and that no heat is lost, what is the change in the temperature of the shot if the tube is 1.0 m long, there are 100 g of shot, and the tube is inverted 10 times? (The specific heat of lead is 0.128 kJ/kg · K.)
A) 0.77 Cº
B) 0.077 Cº
C) 2.5 Cº
D) 7.7 Cº
E) 0.25 Cº

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Multiple Choice

Q 51Q 51

The figure shows a schematic of Joule's classic experiment, in which weights are dropped a certain distance. As the weights drop, they turn a paddle immersed in water. The experiment proves that
A) mechanical energy can be transformed into heat.
B) 1 cal of heat equals 4.184 J.
C) work and heat cannot be separated.
D) in order to change the temperature of the water you have to do work on it.
E) (A) and (B)

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Multiple Choice

Q 52Q 52

The percentage of mechanical energy that can theoretically be turned into heat energy according to the first law of thermodynamics is
A) 100%
B) 90%
C) 75%
D) 50%
E) 0%

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Multiple Choice

Q 53Q 53

A state variable is one that allows other variables to be determined using a relationship. Which of the following variables are state variables?
A) P, V, and T
B) Internal energy, U
C) W and Q
D) (A) and (B)
E) (A), (B), and (C)

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Multiple Choice

Q 54Q 54

The first law of thermodynamics has as its basis the same fundamental principle as
A) the continuity principle.
B) conservation of energy
C) Newton's law of universal gravitation.
D) static equilibrium.
E) the conservation of linear momentum.

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Multiple Choice

Q 55Q 55

The first law of thermodynamics is most closely related to
A) the definition of absolute zero.
B) the definition of an ideal gas.
C) the conservation of energy.
D) thermal expansion.
E) the conservation of momentum.

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Multiple Choice

Q 56Q 56

Suppose you do 75 kJ of work on a system consisting of 10 kg of water by stirring it with a paddle wheel. During this process, 40 kcal of heat is removed. The change in the internal energy of the system is
A) -35 kJ
B) -115 kJ
C) -134 kJ
D) -242 kJ
E) -156 kJ

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Multiple Choice

Q 57Q 57

In a certain process, 500 cal of heat are supplied to a system consisting of a gas confined in a cylinder. At the same time, 500 J of work are done by the gas by expansion. The increase in thermal energy of the gas is approximately
A) zero
B) 1.00 kJ
C) 1.59 kJ
D) 2.09 kJ
E) 2.59 kJ

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Multiple Choice

Q 58Q 58

How much internal energy is contained in 1 mole of monatomic gas at STP?
A) zero
B) 1.11 kJ
C) 2.22 kJ
D) 3.33 kJ
E) 5.55 kJ

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Multiple Choice

Q 59Q 59

Two containers of equal volume are connected by a stopcock as shown below. One container is filled with a gas at a pressure of 1 atm and temperature of 293 K while the other container is evacuated so that it is under vacuum. The containers are thermally isolated from the surrounding so no heat enters or escaped from the system. The stopcock is then opened allowing the gas from one container to fill the other. What is the final temperature of the gas after it has come to equilibrium?
A) 136.5 K
B) 273 K
C) 293 K
D) 195 K
E) undetermined

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Multiple Choice

Q 60Q 60

In a certain thermodynamic process, 1000 cal of heat are added to a gas confined in a cylinder. At the same time, 1000 J of work are done by the gas as it expands. The increase in internal energy of the gas is
A) zero
B) 3186 J
C) -239 J
D) 5186 J
E) 1239 J

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Multiple Choice

Q 61Q 61

During a certain thermodynamic process, 418 J of work are done on a system and 214 cal of heat are transferred to the system. The change in internal energy during the process is
A) 314 cal
B) 114 cal
C) 468 cal
D) 368 cal
E) 632 cal

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Multiple Choice

Q 62Q 62

In a certain thermodynamic process, 20 cal of heat are removed from a system and 30 cal of work are done on the system. The internal energy of the system
A) increases by 10 cal.
B) decreases by 10 cal.
C) increases by 50 cal.
D) decreases by 50 cal.
E) decreases by 20 cal.

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Multiple Choice

Q 63Q 63

A liquid is irregularly stirred in a well-insulated container and thereby undergoes a rise in temperature. Regarding the liquid as a system, you can say that
A) heat has been transferred.
B) the rise in temperature indicates work done by the system.
C) the internal energy has been unchanged.
D) the work done by the system equals the work done on the system.
E) there is a positive change in internal energy.

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Multiple Choice

Q 64Q 64

An ideal gas undergoes a cyclic process in which total (positive) work W is done by the gas. What total heat is added to the gas in one cycle?
A) W
B) -W
C) zero
D) 2W
E) W/2

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Multiple Choice

Q 65Q 65

An ideal gas is heated so that it expands at constant pressure. The gas does work W. What heat is added to the gas?
A) W
B) -W
C) zero
D) more than W
E) less than W

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Multiple Choice

Q 66Q 66

The pressure of a gas in an isobaric expansion remains constant. In such an expansion,
A) no work is done.
B) work is done by the gas.
C) work is done on the gas.
D) "isobaric" and "expansion" are contradictory terms.
E) work is or is not done depending on whether the temperature of the gas changes.

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Multiple Choice

Q 67Q 67

A balloon contains gas at a pressure 1.2 atm (1 atm = 101.3 kPa) and has a volume of
0)10m

^{3}. More gas is pumped into the balloon at constant pressure until the volume is doubled. How much work is done by the pump? A) 12 J B) 24 kJ C) 24 J D) 12 kJ E) 6.1 kJFree

Multiple Choice

Q 68Q 68

The work done by an ideal gas in an isothermal expansion from volume V

_{1}to volume V_{2}is given by the formula: W = nRT ln(V_{2}/V_{1}) Standard atmospheric pressure (1 atm) is 101.3 kPa. If 1.0 L of He gas at room temperature (20ºC) and 1.0 atm of pressure is compressed isothermally to a volume of 100 mL, how much work is done on the gas? A) 5.6 kJ B) 4.7 10^{2}J C) 4.7 10^{2}kJ D) 2.3 10^{2}kJ E) 2.3 10^{2}JFree

Multiple Choice

Q 69Q 69

An ideal gas system changes from state i to state f by paths iaf and ibf. If the heat added along iaf is Q

_{iaf}= 50 cal, the work along iaf is W_{iaf}= 20 cal. Along ibf, if Q_{ibf}= 40 cal, the work done, W_{ibf}, is A) 10 cal B) 20 cal C) 30 cal D) 40 cal E) 50 calFree

Multiple Choice

Q 70Q 70

An ideal gas system changes from state i to state f by paths iaf and ibf. If the heat added along iaf is Q

_{iaf}= 50 cal, the work along iaf is W_{iaf}= 20 cal. Along ibf, if Q_{ibf}= 40 cal, the work done, W_{iaf}, is A) 10 cal B) 20 cal C) 30 cal D) 40 cal E) 50 calFree

Multiple Choice

Q 71Q 71

An ideal gas undergoes a cyclic expansion and compression along the path abca as shown above. The work done along ca of the cycle is the area
A) shaded blue.
B) shaded yellow.
C) shaded blue and yellow.
D) negative of the area shaded blue.
E) negative of the area shaded yellow.

Free

Multiple Choice

Q 72Q 72

An ideal gas undergoes a cyclic expansion and compression along the path abca as shown above. The work done along bc of the cycle is the area
A) shaded blue.
B) shaded yellow.
C) shaded blue and yellow.
D) negative of the area shaded blue.
E) negative of the area shaded yellow.

Free

Multiple Choice

Q 73Q 73

A gas expands along path ABC. The work done by the gas in this expansion is
A) 4.0 10

^{5}J B) 5.0 10^{5}J C) 6.0 10^{5}J D) 7.0 10^{5}J E) 8.0 10^{5}JFree

Multiple Choice

Q 74Q 74

The work done by the system shown in the graph in expanding from 5 to 6 L is
A) the same as for any l-L interval between A and B.
B) 3.8 mJ
C) 2.2 mJ
D) 26 mJ
E) 9.0 mJ

Free

Multiple Choice

Q 75Q 75

A reversible heat engine has the PV graph shown. The net work performed in one cycle is approximately
A) zero
B) 2.0 kJ
C) 4.2 kJ
D) 5.5 kJ
E) 10 kJ

Free

Multiple Choice

Q 76Q 76

The work done by a gas on a piston can be obtained from the graph, provided the abscissa represents the
A) internal energy.
B) temperature.
C) density.
D) volume.
E) time.

Free

Multiple Choice

Q 77Q 77

A reversible heat engine has the PV graph shown. The work done during the entire cycle is
A) zero
B) 2.5 kJ
C) 6.0 kJ
D) 2.0 kJ
E) 5.0 kJ

Free

Multiple Choice

Q 78Q 78

A system is said to go through an isothermal process if it
A) remains at a constant temperature.
B) does no work on its surroundings.
C) remains in the same state.
D) neither gains nor loses heat.
E) gains or loses heat at a constant rate.

Free

Multiple Choice

Q 79Q 79

The curve on the graph of pressure versus density that best represents an isothermal process is
A) 1
B) 2
C) 3
D) 4
E) 5

Free

Multiple Choice

Q 80Q 80

The equation of state for a certain gas under isothermal conditions is
PV = 31.2,
Where the units are SI. The work done by this gas as its volume increases isothermally from 0.2 m

^{3}to 0.8 m^{3}is approximately A) 2.86 J B) 28.6 J C) 43.3 J D) 71.8 J E) 115 JFree

Multiple Choice

Q 81Q 81

The equation of state for a certain gas under isothermal conditions is
PV = 31.2,
Where the units are SI. The work done by this gas as its volume increases isothermally from 1 L to 10 L is approximately
A) 13.6 J
B) 31.2 J
C) 71.8 J
D) 281 J
E) 312 J

Free

Multiple Choice

Q 82Q 82

Use the following to answer questions :
-An ideal gas initially at 50ºC and pressure P

_{1}= 100 kPa occupies a volume V_{1}= 3 L. It undergoes a quasi-static, isothermal expansion until its pressure is reduced to 50 kPa. How much work was done by the gas during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 116 J B) 208 J C) 256 J D) 304 J E) 416 JFree

Multiple Choice

Q 83Q 83

Use the following to answer questions :
-An ideal gas initially at 50ºC and pressure P

_{1}= 250 kPa occupies a volume V_{1}= 4.5 L. It undergoes a quasistatic, isothermal expansion until its pressure is reduced to 150 kPa. How much work was done by the gas during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 116 J B) 320 J C) 575 J D) 640 J E) 850 JFree

Multiple Choice

Q 84Q 84

Use the following to answer questions :
-An ideal gas initially at 100ºC and pressure P

_{1}= 250 kPa occupies a volume V_{1}= 4.5 L. It undergoes a quasistatic, isothermal expansion until its pressure is reduced to 150 kPa. How much does the internal energy of the gas change during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 116 J B) 320 J C) 575 J D) 640 J E) The internal energy does not change during this process.Free

Multiple Choice

Q 85Q 85

Use the following to answer questions :
-An ideal gas initially at 50ºC and pressure P

_{1}= 100 kPa occupies a volume V_{1}= 3 L. It undergoes a quasistatic, isothermal expansion until its pressure is reduced to 50 kPa. How much does the internal energy of the gas change during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 116 J B) 208 J C) 256 J D) 304 J E) The internal energy does not change during this process.Free

Multiple Choice

Q 86Q 86

Use the following to answer questions :
-An ideal gas initially at 100ºC and pressure P

_{1}= 250 kPa occupies a volume V_{1}= 4.5 L. It undergoes a quasistatic, isothermal expansion until its pressure is reduced to 150 kPa. How much heat enters the gas during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 116 J B) 320 J C) 575 J D) 640 J E) 850 JFree

Multiple Choice

Q 87Q 87

Use the following to answer questions :
-One mole of an ideal gas ( = 5/3) expands adiabatically and quasistatically from a pressure P

_{1}= 3 atm and a temperature of 30ºC to a pressure P_{2}= 1 atm. How much work is done by the gas during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 50.3 kJ B) 63.5 kJ C) 95.9 kJ D) 131 kJ E) 158 kJFree

Multiple Choice

Q 88Q 88

Use the following to answer questions :
-An ideal gas initially at 50ºC and pressure P

_{1}= 100 kPa occupies a volume V_{1}= 3 L. It undergoes a quasistatic, isothermal expansion until its pressure is reduced to 50 kPa. How much heat enters the gas during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 116 J B) 208 J C) 256 J D) 304 J E) 416 JFree

Multiple Choice

Q 89Q 89

Use the following to answer questions :
-One mole of an ideal gas ( = 5/3) expands adiabatically and quasistatically from a pressure P

_{1}= 6 atm and a temperature of 50ºC to a pressure P_{2}= 4 atm. How much work is done by the gas during this process? R = 8.314 J/mol·K = 8.206 L·atm/mol·K. A) 50.3 kJ B) 56.2 kJ C) 95.9 kJ D) 131 kJ E) 158 kJFree

Multiple Choice

Q 90Q 90

The diagram above show the state of an ideal gas going from (V

_{1}, P_{1}) to a final state. Which path best represents an isothermal expansion? A) 1 B) 2 C) 3 D) 4 E) none of the pathsFree

Multiple Choice

Q 91Q 91

The internal energy for a diatomic gas is given by U = 5nRT/2. Calculate the internal energy of a 100 g mixture of oxygen (20%) and nitrogen (80%) gas at 25C. (The molar weight of O

_{2}= 32 g, and the molar weight of N_{2}= 28 g.) A) 21.6 kJ B) 1.80 kJ C) 12.1 kJ D) 13.0 kJ E) 1.10 kJFree

Multiple Choice

Q 92Q 92

From the measured molar heat capacities and the equipartition theorem, for a polyatomic gas molecule the number of degrees of freedom due to translational motion are
A) 3
B) 6
C) 5
D) 2
E) 7

Free

Multiple Choice

Q 93Q 93

From the measured molar heat capacities and the equipartition theorem, for a diatomic gas molecule the number of degrees of freedom from rotational motion are
A) 3
B) 0
C) 5
D) 2
E) 6

Free

Multiple Choice

Q 94Q 94

An ideal monatomic gas has a molar heat capacity C

_{mp}at constant pressure. What is the molar heat capacity at constant volume of an ideal diatomic gas? A) C_{mp }B) C_{mp}+ R C) C_{mp}- R D) C_{mp}+ 3R/2 E) C_{mp}- 3R/2Free

Multiple Choice

Q 95Q 95

The molar heat capacity at constant volume of a gas is found to be 20.74 J/mol · K. What is the molar heat capacity at constant pressure of this gas? (The ideal-gas law constant is R = 8.31 J/mol · K)
A) 12.4 J/mol · K
B) 29.0 J/mol · K
C) 33.2 J/mol · K
D) 41.5 J/mol · K
E) 8.28 J/mol · K

Free

Multiple Choice

Q 96Q 96

A gas has a molar heat capacity at constant volume of 28.39 J/mol · K. Assume the equipartition theorem to be valid. How many degrees of freedom (including translational) are there for the molecules of this gas? (the ideal-gas law constant is R = 8.31 J/mol · K)
A) 1
B) 3
C) 4
D) 5
E) 7

Free

Multiple Choice

Q 97Q 97

"The specific heat of an ideal gas at constant pressure C

_{p}is greater than the specific heat of a gas at constant volume C_{v}." Which of the following describes this statement? A) The statement is true because there is always more gas at constant pressure. B) The statement is true because, to raise the temperature of a gas at constant pressure, work must be done by the gas. C) The statement is true because, to raise the temperature of a gas at constant volume, work must be done by the gas. D) The statement is not true; C_{v}> C_{p}. E) The statement is not true; C_{p}= C_{v}.Free

Multiple Choice

Q 98Q 98

The difference in the molar heat capacity at constant P and constant V is (assume ideal gas).
A) equal to R for monotomic gas.
B) equal to 2R for diatomic gas.
C) equal to NR for polyatomic gas, where N is the number of atoms in a polyatomic molecules.
D) equal to R for all gases.
E) (A) and (D)

Free

Multiple Choice

Q 99Q 99

The internal energy of a solid depends on the number of degrees of freedom available to each atom. Which of the following statements is correct concerning these degrees of freedom in a solid?
A) Three are due to translational, two are rotational, and one is vibrational.
B) Three are due to kinetic, and three from potential energies of vibration.
C) Three are due to translational, and two are rotational.
D) There are three, and all are due to translational motion.
E) Three are vibrational, and three are rotational.

Free

Multiple Choice

Q 100Q 100

The fact that most solids have molar heat capacities of approximately 3R, where R is the universal gas constant, is known as
A) the first law of thermodynamics.
B) the equipartition theorem.
C) the Dulong-Petit law.
D) Joule's principle.
E) None of these is correct.

Free

Multiple Choice

Q 101Q 101

The equipartition theorem
A) fails to explain the fact that monatomic atoms do not rotate about any of three possible mutually perpendicular axes.
B) is unable to account for the dependency of heat capacities on temperature.
C) fails to predict correctly the heat capacities of solids at high temperatures.
D) does not acknowledge the quantization of energy.
E) is described by all of these

Free

Multiple Choice

Q 102Q 102

The pressure of a mass of air at 20C is halved adiabatically. If the ratio of C

_{p}to C_{v}for air is 1.41, calculate the resulting volume. A) 2.66 times the original volume B) 1.63 times the original volume C) 2.00 times the original volume D) 0.50 times the original volume E) 0.61 times the original volumeFree

Multiple Choice

Q 103Q 103

The pressure of a mass of air at 20C is halved adiabatically. If the ratio of C

_{p}to C_{v}for air is 1.41, calculate the resulting temperature. A) 240C B) 85.0C C) 33.0C D) 126C E) 16.0CFree

Multiple Choice

Q 104Q 104

Calculate the speed of sound in hydrogen gas (H

_{2}) at 20C given the ratio of C_{p}to C_{v}is 1.41. (Molar mass of H_{2 }= 2 g/mol.) A) 1850 m/s B) 1150 m/s C) 342 m/s D) 1310 m/s E) 41 m/sFree

Multiple Choice

Q 105Q 105

The diagram above show the state of an ideal gas going from (V

_{1},P_{1}) to a final state. Which path best represents adiabatic expansion? A) 1 B) 2 C) 3 D) 4 E) none of the pathsFree

Multiple Choice

Q 106Q 106

An ideal gas with an initial volume of 3 L at a pressure of 2 atm is compressed adiabatically until it has a volume of 2 L; then it is cooled at constant volume until its temperature drops to its initial value. The final pressure is
A) atm
B) 2 atm
C) 3 atm
D) 4/3 atm
E) 6 atm

Free

Multiple Choice

Q 107Q 107

In a system composed of an ideal gas contained in a cylinder fitted with a piston, a reversible adiabatic expansion causes the temperature of the gas to drop because
A) heat is given up by the system when the piston moves.
B) the pressure of the gas remains constant.
C) work is done on the system as the gas expands.
D) work done by the system is done entirely at the expense of its internal energy.
E) heat is absorbed by the piston when it does work.

Free

Multiple Choice

Q 108Q 108

A gas can absorb heat without changing temperature if at the same time
A) it is at its critical temperature.
B) it is kept at constant volume.
C) it is slowly compressed.
D) it does sufficient work in expanding.
E) it is confined by an adiabatic envelope.

Free

Multiple Choice

Q 109Q 109

In an adiabatic reversible compression of an ideal gas, there is a decrease in
A) pressure.
B) temperature.
C) internal energy.
D) volume.
E) rms molecular velocity.

Free

Multiple Choice

Q 110Q 110

In a system composed of gas contained in a cylinder fitted with a piston, an adiabatic expansion causes the temperature of the gas to drop because
A) heat is given up by the system when the piston moves.
B) the pressure of the gas remains constant.
C) work is done on the system as the gas expands.
D) work done by the system is entirely at the expense of its internal energy.
E) heat is absorbed by the piston when it does work.

Free

Multiple Choice

Q 111Q 111

A system is said to go through an adiabatic process if, throughout the process,
A) it maintains a constant ratio of pressure to temperature.
B) it remains at a constant temperature.
C) it loses no heat to its surroundings and gains none from them.
D) its total energy increases.
E) it does no work on its surroundings.

Free

Multiple Choice

Q 112Q 112

A cylinder contains 20 L of air at 1 atm. The ratio of C

_{p}to C_{V}for air is 1.41. If this sample of air is compressed adiabatically to a volume of 5 L, the pressure after compression is approximately A) 2.7 atm B) 7.1 atm C) 8.4 atm D) 4.0 atm E) 9.7 atmFree

Multiple Choice

Q 113Q 113

At a particular point on a PV diagram, the magnitude of the slope of a curve that represents an adiabatic process is
A) zero.
B) infinite.
C) the same as that of an isotherm through the same point.
D) less than that of an isotherm through the same point.
E) greater than that of an isotherm through the same point.

Free

Multiple Choice

Q 114Q 114

When a gas is compressed adiabatically,
A) the pressure increases and the internal energy decreases.
B) the pressure increases and work is performed by the gas.
C) the temperature decreases and the internal energy increases.
D) the pressure is unchanged and heat flows out of the system.
E) work is done on the system and the temperature rises.

Free

Multiple Choice