Question 1

A certain ideal gas has a molar specific heat at constant volume 7R/2.What is its molar specific heat at constant pressure?

Accepted Answer

A) 5R/2 
B) 3R/2 
C) 8R 
D) 9R/2 
E) 6R 
A) 5R/2 
B) 3R/2 
C) 8R 
D) 9R/2 
E) 6R D

Question 2

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.

Accepted Answer

A) 27% 
B) 0.27% 
C) 100% 
D) 1.0% 
E) 15% 
A) 27% 
B) 0.27% 
C) 100% 
D) 1.0% 
E) 15% A

Question 3

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?

Accepted Answer

A) 1.98 K 
B) 0.180 K 
C) 157 K 
D) 0.160 K 
A) 1.98 K 
B) 0.180 K 
C) 157 K 
D) 0.160 K A

Question 4

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?

Accepted Answer

A) 105 J 
B) 130 J 
C) 780 J 
D) 520 J 
E) 340 J 
A) 105 J 
B) 130 J 
C) 780 J 
D) 520 J 
E) 340 J

Question 5

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?

Accepted Answer

A) 0 J 
B) 5.0 J 
C) -5.0 J 
D) -10 J 
A) 0 J 
B) 5.0 J 
C) -5.0 J 
D) -10 J

Question 6

When a gas expands adiabatically,

Accepted Answer

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) 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.

Question 7

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?

Accepted Answer

A) 712 J 
B) 586 J 
C) 460 J 
D) 126 J 
A) 712 J 
B) 586 J 
C) 460 J 
D) 126 J

Question 8

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?

Accepted Answer

A) 200 K 
B) 245 K 
C) 350 K 
D) 455 K 
E) 600 K 
A) 200 K 
B) 245 K 
C) 350 K 
D) 455 K 
E) 600 K

Question 9

A rigid container is filled with 4.0 mol of air with CV = 2.5R.How much does the internal (thermal)energy of the air change if its temperature rises from  
To  
(R = 8.31 J/mol ∙ K)

Accepted Answer

A) 35,800 J 
B) 430 J 
C) 3,580 J 
D) 8,940 J 
A) 35,800 J 
B) 430 J 
C) 3,580 J 
D) 8,940 J

Question 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. )

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 11

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?

Accepted Answer

A) 0 J 
B) 50 J 
C) -50 J 
D) 25 J 
E) -25 J 
A) 0 J 
B) 50 J 
C) -50 J 
D) 25 J 
E) -25 J

Question 12

An expansion process on an ideal diatomic ideal gas for which CV = 5/2 R has a linear path between the initial and final coordinates on a pV diagram.The coordinates of the initial state are: the pressure is  
The volume is  
And the temperature is  
The final pressure is  
And the final temperature is  
What is the change in the internal (thermal)energy of the gas,during this process? (R = 8.31 J/mol ∙ K)

Accepted Answer

A) -2,900 J 
B) -1,700 J 
C) 2,900 J 
D) 1,700 J 
E) 0 J 
A) -2,900 J 
B) -1,700 J 
C) 2,900 J 
D) 1,700 J 
E) 0 J

Question 13

The temperature of an ideal gas in a sealed rigid 0.60-  
Container is reduced from 460 K to  
The final pressure of the gas is  
The molar heat capacity at constant volume of the gas is 28.0 J/mol ∙ K.How much heat is absorbed by the gas during this process? (R = 8.31 J/mol ∙ K)

Accepted Answer

A) -130 kJ 
B) -170 kJ 
C) 130 kJ 
D) 170 kJ 
E) 0 kJ 
A) -130 kJ 
B) -170 kJ 
C) 130 kJ 
D) 170 kJ 
E) 0 kJ

Question 14

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

Question 15

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

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 16

A container with rigid walls is filled with 4.00 mol of air at 17°C with CV = 2.5R.What is the final temperature of the air if its internal energy is increased by 28 kJ? (R = 8.31 J/mol ∙ K)

Accepted Answer

A) 337°C 
B) 354°C 
C) 337 K 
D) 354 K 
E) 610 K 
A) 337°C 
B) 354°C 
C) 337 K 
D) 354 K 
E) 610 K

Question 17

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?

Accepted Answer

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. 
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.

Question 18

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?

Accepted Answer

A) -225 kJ 
B) -1075 kJ 
C) 1075 kJ 
D) 225 kJ 
E) 276 kJ 
A) -225 kJ 
B) -1075 kJ 
C) 1075 kJ 
D) 225 kJ 
E) 276 kJ

Question 19

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?

Accepted Answer

A) 3.9 
B) 4.9 
C) 2.9 
D) 0.26 
E) 22 
A) 3.9 
B) 4.9 
C) 2.9 
D) 0.26 
E) 22

Question 20

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?

Accepted Answer

A) 0 J 
B) 400 J 
C) -400 J 
D) -200 J 
E) 200 J 
A) 0 J 
B) 400 J 
C) -400 J 
D) -200 J 
E) 200 J

Exam 18: The Laws of Thermodynamics

A certain ideal gas has a molar specific heat at constant volume 7R/2.What is its molar specific heat at constant pressure?

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.

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?

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?

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?

When a gas expands adiabatically,

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 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 rigid container is filled with 4.0 mol of air with CV = 2.5R.How much does the internal (thermal)energy of the air change if its temperature rises from To (R = 8.31 J/mol ∙ K)

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. )

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?

The temperature of an ideal gas in a sealed rigid 0.60- Container is reduced from 460 K to The final pressure of the gas is The molar heat capacity at constant volume of the gas is 28.0 J/mol ∙ K.How much heat is absorbed by the gas during this process? (R = 8.31 J/mol ∙ K)

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

A container with rigid walls is filled with 4.00 mol of air at 17°C with CV = 2.5R.What is the final temperature of the air if its internal energy is increased by 28 kJ? (R = 8.31 J/mol ∙ K)

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?

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 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 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?

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

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

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A rigid container is filled with 4.0 mol of air with C_V = 2.5R.How much does the internal (thermal)energy of the air change if its temperature rises from To (R = 8.31 J/mol ∙ K)

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 container with rigid walls is filled with 4.00 mol of air at 17°C with C_V = 2.5R.What is the final temperature of the air if its internal energy is increased by 28 kJ? (R = 8.31 J/mol ∙ K)