Question 1

The gas in a perfectly insulated but flexible container does work at a rate of $13 \mathrm {~W} .$ At what rate is the internal (thermal) energy of the gas changing?

Accepted Answer

A)  -13 W 
B)  13 W 
C)  0 W 
D)  6.5 W 
A)  -13 W 
B)  13 W 
C)  0 W 
D)  6.5 W A

Question 2

An ideal Carnot refrigerator with a performance coefficient (COP) of 5.0 cools items inside of it to $5.0 ^ { \circ } \mathrm { C }$ What is the high temperature needed to operate this refrigerator?

Accepted Answer

A)  61° C 
B)  1395° C 
C)  6° C 
D)  30° C 
A)  61° C 
B)  1395° C 
C)  6° C 
D)  30° C A

Question 3

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?

Accepted Answer

A)  200 K 
B)  220 K 
C)  240 K 
D)  260 K 
E)  280 K 
A)  200 K 
B)  220 K 
C)  240 K 
D)  260 K 
E)  280 K C

Question 4

Which one of the following is a true statement?

Accepted Answer

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. 
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.

Question 5

The temperature in your classroom is closest to

Accepted Answer

A)  68 K. 
B)  68°C. 
C)  50°C. 
D)  295 K. 
A)  68 K. 
B)  68°C. 
C)  50°C. 
D)  295 K.

Question 6

A temperature change of 20 C° corresponds to a Fahrenheit temperature change of

Accepted Answer

A)  68 F°. 
B)  11 F°. 
C)  36 F°. 
D)  18 F°. 
A)  68 F°. 
B)  11 F°. 
C)  36 F°. 
D)  18 F°.

Question 7

An ideal Carnot engine is operated between a hot and a cold reservoir. The temperature difference between the two reservoirs is 284°C. If the efficiency of this ideal engine is 24.0%, find the temperature of the cold reservoir in degrees Celsius.

Accepted Answer

The answer of An ideal Carnot engine is operated between...

Question 8

The figure shows a p$V$ diagram for a gas going through a cycle from A to B to C and back to A. From point A to point B, the gas absorbs 50 J of heat and finds its internal (thermal) energy has increased by 20 J. Going from B to C, the internal (thermal) energy decreases by 5.0 J.
(a) How much work was done by the gas from A to B?
(b) How much heat was absorbed by the gas from B to C?
(c) How much work was done by the gas going from B to C?

Accepted Answer

(a) 30 J (

Question 9

A fluid in an insulated, flexible bottle is heated by a high resistance wire and expands. If $9.0 \mathrm {~kJ}$ of heat is applied to the system and it does $5.0 \mathrm {~kJ}$ of work, how much does the internal (thermal) energy of the fluid change?

Accepted Answer

A)  4.0 kJ 
B)  14 kJ 
C)  -4.0 kJ 
D)  45 kJ 
A)  4.0 kJ 
B)  14 kJ 
C)  -4.0 kJ 
D)  45 kJ

Question 10

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 = $5.4 \text { atm? }$

Accepted Answer

A)  220 J 
B)  440 J 
C)  870 J 
D)  1100 J 
A)  220 J 
B)  440 J 
C)  870 J 
D)  1100 J

Question 11

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.)

Accepted Answer

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)  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.

Question 12

A certain automobile engine takes in 4.00 kJ of heat and performs 1.10 kJ of mechanical work in each cycle.
(a) Calculate the engine's efficiency.
(b) How much heat is "wasted" in each cycle?

Accepted Answer

(a) 27.5%

Question 13

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?

Accepted Answer

A)  36 kW 
B)  41 kW 
C)  57 kW 
D)  60 kW 
A)  36 kW 
B)  41 kW 
C)  57 kW 
D)  60 kW

Question 14

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?

Accepted Answer

A)  0 J 
B)  100 J 
C)  200 J 
D)  -200 J 
A)  0 J 
B)  100 J 
C)  200 J 
D)  -200 J

Question 15

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 16

A cylinder contains 8.8 moles of ideal gas, initially at a temperature of 126°C. The cylinder is provided with a frictionless piston, which maintains a constant pressure of $5.3 \times 10 ^ { 5 } \mathrm {~Pa}$ on the gas. The gas is cooled until its temperature has decreased to $27 ^ { \circ } \mathrm { C }$ For the gas $\mathrm { C } _ { \mathrm { V } } = 13.73 \mathrm {~J} / \mathrm { mol } \cdot \mathrm { K }$ The ideal gas constant is R = 8.314 J/mol ∙ K. For this process, calculate:
(a) the work done by gas
(b) the net change in the internal (thermal) energy of the gas
(c) the heat transferred to the gas.

Accepted Answer

(a) -7200

Question 17

A monatomic ideal gas undergoes an isothermal expansion at 300 K, as the volume increased from $0.010 \mathrm {~m} ^ { 3 }$ to $0.040 \mathrm {~m} ^ { 3 }$ The final pressure is $130 \mathrm { kPa } \text {. }$ What is the change in the internal (thermal) energy of the gas during this process? (R = 8.31 J/mol ∙ K)

Accepted Answer

A)  0.0 kJ 
B)  3.6 kJ 
C)  7.2 kJ 
D)  -3.6 kJ 
E)  -7.2 kJ 
A)  0.0 kJ 
B)  3.6 kJ 
C)  7.2 kJ 
D)  -3.6 kJ 
E)  -7.2 kJ

Question 18

An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at $1.76 \mathrm {~K}$ has an efficiency of $40.0 \%$ What is the temperature of the warm reservoir?

Accepted Answer

A)  2.93 K 
B)  0.0500 K 
C)  106 K 
D)  0.0400 K 
A)  2.93 K 
B)  0.0500 K 
C)  106 K 
D)  0.0400 K

Question 19

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?

Accepted Answer

A)  46% 
B)  54% 
C)  86% 
D)  27% 
E)  13% 
A)  46% 
B)  54% 
C)  86% 
D)  27% 
E)  13%

Question 20

An ideal gas undergoes an isothermal expansion. During this process, its entropy

Accepted Answer

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

Exam 11: Using Energy

The gas in a perfectly insulated but flexible container does work at a rate of 13 W.13 \mathrm {~W} .13 W. At what rate is the internal (thermal) energy of the gas changing?

An ideal Carnot refrigerator with a performance coefficient (COP) of 5.0 cools items inside of it to 5.0∘C5.0 ^ { \circ } \mathrm { C }5.0∘C What is the high temperature needed to operate this refrigerator?

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?

Which one of the following is a true statement?

The temperature in your classroom is closest to

A temperature change of 20 C° corresponds to a Fahrenheit temperature change of

An ideal Carnot engine is operated between a hot and a cold reservoir. The temperature difference between the two reservoirs is 284°C. If the efficiency of this ideal engine is 24.0%, find the temperature of the cold reservoir in degrees Celsius.

A fluid in an insulated, flexible bottle is heated by a high resistance wire and expands. If 9.0 kJ9.0 \mathrm {~kJ}9.0 kJ of heat is applied to the system and it does 5.0 kJ5.0 \mathrm {~kJ}5.0 kJ of work, how much does the internal (thermal) energy of the fluid change?

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 = 5.4 atm? 5.4 \text { atm? }5.4 atm?

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 certain automobile engine takes in 4.00 kJ of heat and performs 1.10 kJ of mechanical work in each cycle. (a) Calculate the engine's efficiency. (b) How much heat is "wasted" in each cycle?

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?

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?

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?

An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at 1.76 K1.76 \mathrm {~K}1.76 K has an efficiency of 40.0%40.0 \%40.0% What is the temperature of the warm reservoir?

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?

An ideal gas undergoes an isothermal expansion. During this process, its entropy

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The gas in a perfectly insulated but flexible container does work at a rate of $13 \mathrm {~W} .$ At what rate is the internal (thermal) energy of the gas changing?

An ideal Carnot refrigerator with a performance coefficient (COP) of 5.0 cools items inside of it to $5.0 ^ { \circ } \mathrm { C }$ What is the high temperature needed to operate this refrigerator?

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 fluid in an insulated, flexible bottle is heated by a high resistance wire and expands. If $9.0 \mathrm {~kJ}$ of heat is applied to the system and it does $5.0 \mathrm {~kJ}$ of work, how much does the internal (thermal) energy of the fluid change?

An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at $1.76 \mathrm {~K}$ has an efficiency of $40.0 \%$ What is the temperature of the warm reservoir?