Question 1

The entropy of the universe remains constant during a reversible adiabatic change.

Accepted Answer

A) True 
 B)False

Question 2

An ideal monatomic gas undergoes an isothermal expansion. It is correct to affirm that its entropy

Accepted Answer

A)  decreases. 
B)  remains unchanged. 
C)  increases. 
D)  cannot be predicted with the data given. 
A)  decreases. 
B)  remains unchanged. 
C)  increases. 
D)  cannot be predicted with the data given.

Question 3

A monatomic ideal gas at an initial temperature of 390 K is compressed adiabatically from an initial volume of 120 L to a final volume of 40.0 L. What is the final temperature of the gas?

Accepted Answer

A)  124 K 
B)  811 K 
C)  610 K 
D)  775 K 
E)  820 K 
A)  124 K 
B)  811 K 
C)  610 K 
D)  775 K 
E)  820 K

Question 4

Entropy is a state function.

Accepted Answer

A) True 
 B)False

Question 5

A certain Carnot engine has Th = Tc + 35K, and an efficiency of 20.0%. What is Th?

Accepted Answer

A)  70.0 K 
B)  140 K 
C)  175 K 
D)  210 K 
E)  245 K 
A)  70.0 K 
B)  140 K 
C)  175 K 
D)  210 K 
E)  245 K

Question 6

What is the change in entropy of the lead when 2.0 kg of molten lead solidifies?
[Data:
 Lv = 207. kcal/kg at 1744.°C; Lf = 5.9 kcal/kg at 328.°C]

Accepted Answer

Question 7

1.50 moles of an ideal monatomic gas are initially at a temperature of 317 K. If the gas gains 2730 J of heat and performs 780 J of work, what is its final temperature?

Accepted Answer

A)  359 K 
B)  421 K 
C)  526 K 
D)  687 K 
E)  756 K 
A)  359 K 
B)  421 K 
C)  526 K 
D)  687 K 
E)  756 K

Question 8

FIGURE 18-3  
-An ideal gas undergoes the process a→b→c→a shown in Figure 18-3. Pa = Pc = 240 kPa, Vb = Vc = 40 L, Va = 15 L, and Pb = 400 kPa. How much heat is gained by the system in this process?

Accepted Answer

A)  1000 J 
B)  1500 J 
C)  2000 J 
D)  2500 J 
E)  3000 J 
A)  1000 J 
B)  1500 J 
C)  2000 J 
D)  2500 J 
E)  3000 J

Question 9

A monatomic ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be

Accepted Answer

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)  equal to the initial value.. 
E)  impossible to predict on the basis of this data. 
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)  equal to the initial value.. 
E)  impossible to predict on the basis of this data.

Question 10

An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas perform the most work?

Accepted Answer

A)  at constant pressure 
B)  if the pressure increases in proportion to the volume 
C)  if the pressure decreases in proportion to the volume 
D)  at constant temperature 
E)  adiabatically 
A)  at constant pressure 
B)  if the pressure increases in proportion to the volume 
C)  if the pressure decreases in proportion to the volume 
D)  at constant temperature 
E)  adiabatically

Question 11

A monatomic ideal gas expands adiabatically from an initial volume of 72 L and an initial temperature of 350 K until its temperature falls to 290 K. What is the final volume of the gas?

Accepted Answer

A)  95 L 
B)  98 L 
C)  101 L 
D)  104 L 
E)  142 L 
A)  95 L 
B)  98 L 
C)  101 L 
D)  104 L 
E)  142 L

Question 12

4.00 moles of a monatomic ideal gas at a temperature of 340 K are compressed adiabatically from an initial volume of 70.0 L to a final volume of 30.0 L. What is the final pressure in the gas?

Accepted Answer

A)  663 kPa 
B)  581 kPa 
C)  106 kPa 
D)  42.1 MPa 
E)  2.17 MPa 
A)  663 kPa 
B)  581 kPa 
C)  106 kPa 
D)  42.1 MPa 
E)  2.17 MPa

Question 13

FIGURE 18-3  
-An ideal gas undergoes the process a→b→c→a shown in Figure 18-3. The heat gained in process a→b is 546 J, while in process b→c the system loses 62 J. In process a→b the system performs 310 J of work, while in process c→a work is done on the system in the amount of 223 J. How much heat is gained by the system in process c→a?

Accepted Answer

A)  - 397 J 
B)  - 62 J 
C)  223 J 
D)  18 J 
E)  - 236 J 
A)  - 397 J 
B)  - 62 J 
C)  223 J 
D)  18 J 
E)  - 236 J

Question 14

When objects at different temperatures are brought into thermal contact with one another, the resulting spontaneous flow of heat proceeds from the object with the higher

Accepted Answer

A)  thermal conductivity to the one with the lower thermal conductivity. 
B)  specific heat to the one with the lower specific heat. 
C)  heat capacity to the one with the lower capacity. 
D)  temperature to the one with the lower temperature. 
E)  impossible to predict on the basis of this data. 
A)  thermal conductivity to the one with the lower thermal conductivity. 
B)  specific heat to the one with the lower specific heat. 
C)  heat capacity to the one with the lower capacity. 
D)  temperature to the one with the lower temperature. 
E)  impossible to predict on the basis of this data.

Question 15

State the Third Law of Thermodynamics

Accepted Answer

It is impossible to lower the

Question 16

FIGURE 18-1  
-An ideal monatomic gas undergoes the reversible expansion shown in the Figure 18-1, where V2 = 5V1 and P2 = 3P1. How much heat is gained by the gas in this process, in terms of the initial pressure and volume?

Accepted Answer

A)  14 P1V1 
B)  7 P1V1 
C)  21 P1V1 
D)  15 P1V1 
E)  29 P1V1 
A)  14 P1V1 
B)  7 P1V1 
C)  21 P1V1 
D)  15 P1V1 
E)  29 P1V1

Question 17

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?

Accepted Answer

A)  10.4 
B)  9.44 
C)  0.644 
D)  0.533 
E)  0.0962 
A)  10.4 
B)  9.44 
C)  0.644 
D)  0.533 
E)  0.0962

Question 18

A gas expands from an initial volume of 0.040 m3 and an initial pressure of 210 kPa to a final volume of 0.065 m3 while its temperature is kept constant. How much work is done by the system?

Accepted Answer

A)  3.7 kJ 
B)  4.1 kJ 
C)  5.3 kJ 
D)  5.6 kJ 
E)  7.9 kJ 
A)  3.7 kJ 
B)  4.1 kJ 
C)  5.3 kJ 
D)  5.6 kJ 
E)  7.9 kJ

Question 19

A refrigerator has a coefficient of performance equal to 4.2. How much work must be done on the refrigerator in order to remove 250 J of heat from the interior?

Accepted Answer

A)  60 J 
B)  120 J 
C)  250 J 
D)  480 J 
E)  1050 J 
A)  60 J 
B)  120 J 
C)  250 J 
D)  480 J 
E)  1050 J

Question 20

A heat engine has an efficiency of 35.0% and receives 150 J of heat per cycle.
(a) How much work does it perform in each cycle?
(b) How much heat does it exhaust in each cycle?

Accepted Answer

The answer of A heat engine has an efficiency of...

Exam 18: The Laws of Thermodynamics

The entropy of the universe remains constant during a reversible adiabatic change.

An ideal monatomic gas undergoes an isothermal expansion. It is correct to affirm that its entropy

A monatomic ideal gas at an initial temperature of 390 K is compressed adiabatically from an initial volume of 120 L to a final volume of 40.0 L. What is the final temperature of the gas?

Entropy is a state function.

A certain Carnot engine has Th = Tc + 35K, and an efficiency of 20.0%. What is Th?

What is the change in entropy of the lead when 2.0 kg of molten lead solidifies? [Data: Lv = 207. kcal/kg at 1744.°C; Lf = 5.9 kcal/kg at 328.°C]

1.50 moles of an ideal monatomic gas are initially at a temperature of 317 K. If the gas gains 2730 J of heat and performs 780 J of work, what is its final temperature?

FIGURE 18-3 -An ideal gas undergoes the process a→b→c→a shown in Figure 18-3. Pa = Pc = 240 kPa, Vb = Vc = 40 L, Va = 15 L, and Pb = 400 kPa. How much heat is gained by the system in this process?

A monatomic ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be

An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas perform the most work?

A monatomic ideal gas expands adiabatically from an initial volume of 72 L and an initial temperature of 350 K until its temperature falls to 290 K. What is the final volume of the gas?

4.00 moles of a monatomic ideal gas at a temperature of 340 K are compressed adiabatically from an initial volume of 70.0 L to a final volume of 30.0 L. What is the final pressure in the gas?

When objects at different temperatures are brought into thermal contact with one another, the resulting spontaneous flow of heat proceeds from the object with the higher

State the Third Law of Thermodynamics

FIGURE 18-1 -An ideal monatomic gas undergoes the reversible expansion shown in the Figure 18-1, where V2 = 5V1 and P2 = 3P1. How much heat is gained by the gas in this process, in terms of the initial pressure and volume?

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 gas expands from an initial volume of 0.040 m3 and an initial pressure of 210 kPa to a final volume of 0.065 m3 while its temperature is kept constant. How much work is done by the system?

A refrigerator has a coefficient of performance equal to 4.2. How much work must be done on the refrigerator in order to remove 250 J of heat from the interior?

A heat engine has an efficiency of 35.0% and receives 150 J of heat per cycle. (a) How much work does it perform in each cycle? (b) How much heat does it exhaust in each cycle?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

Electric Charges, Forces, and Fields

Electric Potential and Electric Potential Energy

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

Filters

A certain Carnot engine has T_h = T_c + 35K, and an efficiency of 20.0%. What is T_h?

What is the change in entropy of the lead when 2.0 kg of molten lead solidifies? [Data: L_v = 207. kcal/kg at 1744.°C; L_f = 5.9 kcal/kg at 328.°C]

FIGURE 18-3 -An ideal gas undergoes the process a→b→c→a shown in Figure 18-3. P_a = P_c = 240 kPa, V_b = V_c = 40 L, V_a = 15 L, and P_b = 400 kPa. How much heat is gained by the system in this process?

FIGURE 18-1 -An ideal monatomic gas undergoes the reversible expansion shown in the Figure 18-1, where V₂ = 5V₁ and P₂ = 3P₁. How much heat is gained by the gas in this process, in terms of the initial pressure and volume?

A gas expands from an initial volume of 0.040 m³ and an initial pressure of 210 kPa to a final volume of 0.065 m³ while its temperature is kept constant. How much work is done by the system?