Question 1

Use the following to answer question: 
-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?

Accepted Answer

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.

Question 2

At a particular point on a PV diagram, the magnitude of the slope of a curve that represents an adiabatic process is

Accepted Answer

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.

Question 3

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 $\Delta$T. What change in temperature is experienced by body B?

Accepted Answer

A)  $\Delta$T 
B)  3$\Delta$T/2 
C)  2$\Delta$T/3 
D)  6$\Delta$T 
E)  $\Delta$T/2

Question 4

A reversible heat engine has the PV graph shown. The work done during the entire cycle is

Accepted Answer

A)  zero 
B)  2.5 kJ 
C)  6.0 kJ 
D)  2.0 kJ 
E)  5.0 kJ

Question 5

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/cm3, and 879 kJ/kg.)

Accepted Answer

A)  712 s 
B)  1110 s 
C)  450 s 
D)  1450 s 
E)  950 s

Question 6

The specific heat of a gas at constant pressure is

Accepted Answer

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.

Question 7

An ideal gas system changes from state i to state f by paths iaf and ibf. If the heat added along iaf is Qiaf = 50 cal, the work along iaf is Wiaf = 20 cal. Along ibf, if Qibf = 40 cal, the work done, Wiaf, is

Accepted Answer

A)  10 cal 
B)  20 cal 
C)  30 cal 
D)  40 cal 
E)  50 cal

Question 8

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

Accepted Answer

A)  23ºC 
B)  25ºC 
C)  27ºC 
D)  32ºC 
E)  39ºC

Question 9

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

Accepted Answer

A)  3 
B)  6 
C)  5 
D)  2 
E)  7

Question 10

The quantity of heat absorbed by a body is determined from the formula Q = cm(Tf - Ti). A certain metal has a specific heat c = 0.21 cal/g Cº and a mass m = 25.6 g. The initial temperature is Ti = 34.6ºC, and the final temperature Tf = 54.6ºC. The quantity of heat absorbed is

Accepted Answer

A)  +23 cal 
B)  +0.23 cal 
C)  +14 cal 
D)  +110 cal 
E)  +207 cal

Question 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)

Accepted Answer

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

Question 12

When a substance goes directly from a solid state to a gaseous form, the process is known as

Accepted Answer

A)  vaporization. 
B)  evaporization. 
C)  condensation. 
D)  sublimation. 
E)  deposition.

Question 13

How much internal energy is contained in 1 mole of monatomic gas at STP?

Accepted Answer

A)  zero 
B)  1.11 kJ 
C)  2.22 kJ 
D)  3.33 kJ 
E)  5.55 kJ

Question 14

A gas can absorb heat without changing temperature if at the same time

Accepted Answer

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.

Question 15

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

Accepted Answer

A)  3 
B)  0 
C)  5 
D)  2 
E)  6

Question 16

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

Accepted Answer

A)   atm 
B)  2 atm 
C)  3 atm 
D)  4/3 atm 
E)  6 atm

Question 17

A system is said to go through an adiabatic process if, throughout the process,

Accepted Answer

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.

Question 18

"The specific heat of an ideal gas at constant pressure Cp is greater than the specific heat of a gas at constant volume Cv." Which of the following describes this statement?

Accepted Answer

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; Cv > Cp. 
E)  The statement is not true; Cp = Cv.

Question 19

The work done by the system shown in the graph in expanding from 5 to 6 L is

Accepted Answer

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

Question 20

The pressure of a mass of air at 20S1U1P1$\circ$S1S1P0C is halved adiabatically. If the ratio of Cp to Cv for air is 1.41, calculate the resulting volume.

Accepted Answer

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 volume

Exam 18: Heat and the First Law of Thermodynamics

Use the following to answer question: -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?

At a particular point on a PV diagram, the magnitude of the slope of a curve that represents an adiabatic process is

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 $\Delta$ T. What change in temperature is experienced by body B?

A reversible heat engine has the PV graph shown. The work done during the entire cycle is

The specific heat of a gas at constant pressure is

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

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

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

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

When a substance goes directly from a solid state to a gaseous form, the process is known as

How much internal energy is contained in 1 mole of monatomic gas at STP?

A gas can absorb heat without changing temperature if at the same time

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

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 system is said to go through an adiabatic process if, throughout the process,

"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?

The work done by the system shown in the graph in expanding from 5 to 6 L is

The pressure of a mass of air at 20^$\circ$C is halved adiabatically. If the ratio of C_p to C_v for air is 1.41, calculate the resulting volume.

Exam 18: Heat and the First Law of Thermodynamics

Use the following to answer question: -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?

At a particular point on a PV diagram, the magnitude of the slope of a curve that represents an adiabatic process is

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 Δ\DeltaΔ T. What change in temperature is experienced by body B?

A reversible heat engine has the PV graph shown. The work done during the entire cycle is

The specific heat of a gas at constant pressure is

An ideal gas system changes from state i to state f by paths iaf and ibf. If the heat added along iaf is Qiaf = 50 cal, the work along iaf is Wiaf = 20 cal. Along ibf, if Qibf = 40 cal, the work done, Wiaf, is

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

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

The quantity of heat absorbed by a body is determined from the formula Q = cm(Tf - Ti) . A certain metal has a specific heat c = 0.21 cal/g Cº and a mass m = 25.6 g. The initial temperature is Ti = 34.6ºC, and the final temperature Tf = 54.6ºC. The quantity of heat absorbed is

When a substance goes directly from a solid state to a gaseous form, the process is known as

How much internal energy is contained in 1 mole of monatomic gas at STP?

A gas can absorb heat without changing temperature if at the same time

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

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 system is said to go through an adiabatic process if, throughout the process,

"The specific heat of an ideal gas at constant pressure Cp is greater than the specific heat of a gas at constant volume Cv." Which of the following describes this statement?

The work done by the system shown in the graph in expanding from 5 to 6 L is

The pressure of a mass of air at 20 ∘\circ∘ C is halved adiabatically. If the ratio of Cp to Cv for air is 1.41, calculate the resulting volume.

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 $\Delta$ T. What change in temperature is experienced by body B?

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

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

"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?

The pressure of a mass of air at 20^$\circ$C is halved adiabatically. If the ratio of C_p to C_v for air is 1.41, calculate the resulting volume.