Question 1

If 30 kJ of heat flows out of a system and 15 kJ of work is done by the system, then what is the change in internal energy?

Accepted Answer

A)  85 kJ 
B)  45 kJ 
C)  −45 kJ 
D)  15 kJ 
E)  −15 kJ 
A)  85 kJ 
B)  45 kJ 
C)  −45 kJ 
D)  15 kJ 
E)  −15 kJ

Question 2

Four coins are tossed randomly onto a table. The macrostate is defined as the number of heads showing, which can be 0, 1, 2, 3, or 4. A microstate is a specification of the outcome of each individual coin. What value for the number of heads has the greatest number of possible microstates?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
E)  4 
A)  0 
B)  1 
C)  2 
D)  3 
E)  4

Question 3

When an ideal gas adiabatically expands

Accepted Answer

A)  the temperature of the gas changes. 
B)  the internal energy of the gas does not change. 
C)  work is not done on or by the gas. 
D)  no heat is given off or taken in by the gas. 
A)  the temperature of the gas changes. 
B)  the internal energy of the gas does not change. 
C)  work is not done on or by the gas. 
D)  no heat is given off or taken in by the gas.

Question 4

A refrigerator removes heat from the freezing compartment at the rate of 20 kJ and rejects 24 kJ into the room per cycle. How much work is required in each cycle?

Accepted Answer

A)  4 kJ 
B)  20 kJ 
C)  24 kJ 
D)  44 kJ 
A)  4 kJ 
B)  20 kJ 
C)  24 kJ 
D)  44 kJ

Question 5

1.00 mol of oxygen gas (O2) is heated at constant pressure of 1.00 atm from 10.0°C to 25.0°C. From the first law, calculate the change of internal energy of the gas in this process.

Accepted Answer

A)  312 J 
B)  291 J 
C)  365 J 
D)  155 J 
A)  312 J 
B)  291 J 
C)  365 J 
D)  155 J

Question 6

A system in a certain macrostate has 1.2 × 103 microstates. Through some process, the system changes the number of microstates to 3 × 104. What is the change in entropy for the process?

Accepted Answer

A)  1.1 × 10−23 J/K 
B)  2.1 × 10−23 J/K 
C)  4.4 × 10−23 J/K 
D)  5.6 × 10−23 J/K 
A)  1.1 × 10−23 J/K 
B)  2.1 × 10−23 J/K 
C)  4.4 × 10−23 J/K 
D)  5.6 × 10−23 J/K

Question 7

When 1.000 kg of ice melts, 33.00 × 104 J/kg of heat are needed. What is the entropy change of the ice in the melting process?

Accepted Answer

A)  758.0 J/K 
B)  1,209 J/K 
C)  1,684 J/K 
D)  2,316 J/K 
A)  758.0 J/K 
B)  1,209 J/K 
C)  1,684 J/K 
D)  2,316 J/K

Question 8

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

Accepted Answer

A)  zero 
B)  52.5 J 
C)  97.5 J 
D)  150 J 
A)  zero 
B)  52.5 J 
C)  97.5 J 
D)  150 J

Question 9

What physical quantity is represented by the area under a curve on a PV diagram where pressure is in Pa and volume is in m3?

Accepted Answer

A)  Area in meters2 
B)  Work in Joules 
C)  Heat in Watts 
D)  Heat in Joules 
E)  Work in Calories 
A)  Area in meters2 
B)  Work in Joules 
C)  Heat in Watts 
D)  Heat in Joules 
E)  Work in Calories

Question 10

On a PV diagram, for a curve representing an isothermal compression of an ideal gas, what is the relationship between the initial P value and the final P value?

Accepted Answer

A)  The initial is greater than the final. 
B)  The initial is less than the final. 
C)  They may be either-it depends on the temperature of the process. 
D)  They may be the same. 
A)  The initial is greater than the final. 
B)  The initial is less than the final. 
C)  They may be either-it depends on the temperature of the process. 
D)  They may be the same.

Question 11

A friend tells you that he knows of a situation in which heat is passed from one body to another body with a higher temperature. He explains that he thinks the 2nd law of thermodynamics must have been violated. Is he correct?

Accepted Answer

A)  No. If the temperature difference is small enough, heat can spontaneously flow from the cooler to the hotter body. 
B)  Yes. Heat cannot pass from a cooler body to a hotter body. 
C)  No. He forgot that if external work is done on the system this is possible. 
D)  No. The cooler body can give up energy to the hotter body by radioactivity or another natural process. 
A)  No. If the temperature difference is small enough, heat can spontaneously flow from the cooler to the hotter body. 
B)  Yes. Heat cannot pass from a cooler body to a hotter body. 
C)  No. He forgot that if external work is done on the system this is possible. 
D)  No. The cooler body can give up energy to the hotter body by radioactivity or another natural process.

Question 12

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

Accepted Answer

A)  zero 
B)  52.5 J 
C)  97.5 J 
D)  150 J 
A)  zero 
B)  52.5 J 
C)  97.5 J 
D)  150 J

Question 13

It can be shown that the change in entropy in heating or cooling a sample is given by the relation ΔS = mc ln (TF/Ti), where m is the mass of the sample, c is the specific heat of the sample, and TF and Ti are the final and initial temperatures, respectively. What is the change in entropy when 10.0 grams of lead with a specific heat of 0.452 J/g K is heated from 10.0°C to 50.0°C?

Accepted Answer

A)  0.45 J/K 
B)  0.60 J/K 
C)  0.90 J/K 
D)  0.30 J/K 
A)  0.45 J/K 
B)  0.60 J/K 
C)  0.90 J/K 
D)  0.30 J/K

Question 14

A refrigerator removes heat from the freezing compartment at the rate of 20 kJ and rejects 24 kJ into the room per cycle. What is the coefficient of performance?

Accepted Answer

A)  0.17 
B)  0.2 
C)  1.2 
D)  5 
E)  6 
A)  0.17 
B)  0.2 
C)  1.2 
D)  5 
E)  6

Question 15

During an isothermal process, 5.0 J of heat are removed from an ideal gas. What is the work done by the gas in the process?

Accepted Answer

A)  zero 
B)  −5.0 J 
C)  +5.0 J 
D)  None of these choices are correct. 
A)  zero 
B)  −5.0 J 
C)  +5.0 J 
D)  None of these choices are correct.

Question 16

A refrigerator extracts 65.0 J of heat from a heat reservoir at 0.00°C. If the coefficient of performance of the refrigerator is 2.50, then how much heat is discharged out of the refrigerator?

Accepted Answer

A)  125 J 
B)  91.0 J 
C)  75.0 J 
D)  55.0 J 
A)  125 J 
B)  91.0 J 
C)  75.0 J 
D)  55.0 J

Question 17

An ideal gas is in contact with a heat reservoir so that it remains at a constant temperature of 300.0 K. The gas is compressed from 24.0 L to 14.0 L. The mechanical device that operates the piston to compress the gas expends 5.00 kJ of energy. How much heat flows between from the heat reservoir to the gas?

Accepted Answer

A)  −3.0 kJ 
B)  −5.1 kJ 
C)  −2.0 kJ 
D)  −5.0 kJ 
A)  −3.0 kJ 
B)  −5.1 kJ 
C)  −2.0 kJ 
D)  −5.0 kJ

Question 18

1.00 mol of oxygen gas (O2) is heated at a constant pressure of 1.00 atm from 10.0°C to 25.0°C. How much heat is absorbed by the gas?

Accepted Answer

A)  389 J 
B)  544 J 
C)  436 J 
D)  288 J 
A)  389 J 
B)  544 J 
C)  436 J 
D)  288 J

Question 19

A monatomic ideal gas at 27°C undergoes an isobaric process from state A to B, followed by an isochoric process from state B to C. What is the total work done by the gas in these two processes? (A = 2 atm, 1 L; B = 2 atm, 2 L; C = 1 atm, 2 L)

Accepted Answer

A)  203 J 
B)  231 J 
C)  187 J 
D)  195 J 
A)  203 J 
B)  231 J 
C)  187 J 
D)  195 J

Question 20

Two coins are tossed randomly onto a table. The macrostate is defined as the number of heads showing, which can be 0, 1, or 2. A microstate is a specification of the outcome of each individual coin. What value for the number of heads has the greatest number of possible microstates?

Accepted Answer

A)  0 
B)  1 
C)  2 
A)  0 
B)  1 
C)  2

Exam 15: Thermodynamics

If 30 kJ of heat flows out of a system and 15 kJ of work is done by the system, then what is the change in internal energy?

Four coins are tossed randomly onto a table. The macrostate is defined as the number of heads showing, which can be 0, 1, 2, 3, or 4. A microstate is a specification of the outcome of each individual coin. What value for the number of heads has the greatest number of possible microstates?

When an ideal gas adiabatically expands

A refrigerator removes heat from the freezing compartment at the rate of 20 kJ and rejects 24 kJ into the room per cycle. How much work is required in each cycle?

1.00 mol of oxygen gas (O2) is heated at constant pressure of 1.00 atm from 10.0°C to 25.0°C. From the first law, calculate the change of internal energy of the gas in this process.

A system in a certain macrostate has 1.2 × 103 microstates. Through some process, the system changes the number of microstates to 3 × 104. What is the change in entropy for the process?

When 1.000 kg of ice melts, 33.00 × 104 J/kg of heat are needed. What is the entropy change of the ice in the melting process?

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

What physical quantity is represented by the area under a curve on a PV diagram where pressure is in Pa and volume is in m3?

On a PV diagram, for a curve representing an isothermal compression of an ideal gas, what is the relationship between the initial P value and the final P value?

A friend tells you that he knows of a situation in which heat is passed from one body to another body with a higher temperature. He explains that he thinks the 2nd law of thermodynamics must have been violated. Is he correct?

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

A refrigerator removes heat from the freezing compartment at the rate of 20 kJ and rejects 24 kJ into the room per cycle. What is the coefficient of performance?

During an isothermal process, 5.0 J of heat are removed from an ideal gas. What is the work done by the gas in the process?

A refrigerator extracts 65.0 J of heat from a heat reservoir at 0.00°C. If the coefficient of performance of the refrigerator is 2.50, then how much heat is discharged out of the refrigerator?

1.00 mol of oxygen gas (O2) is heated at a constant pressure of 1.00 atm from 10.0°C to 25.0°C. How much heat is absorbed by the gas?

A monatomic ideal gas at 27°C undergoes an isobaric process from state A to B, followed by an isochoric process from state B to C. What is the total work done by the gas in these two processes? (A = 2 atm, 1 L; B = 2 atm, 2 L; C = 1 atm, 2 L)

Two coins are tossed randomly onto a table. The macrostate is defined as the number of heads showing, which can be 0, 1, or 2. A microstate is a specification of the outcome of each individual coin. What value for the number of heads has the greatest number of possible microstates?

Introduction

Motion Along a Line

Motion in a Plane

Force and Newtons Laws of Motion

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Sound

Temperature and the Ideal Gas

Heat

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Magnetic Forces and Fields

Electromagnetic Induction

Alternating Current

Electromagnetic Waves

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters

1.00 mol of oxygen gas (O₂) is heated at constant pressure of 1.00 atm from 10.0°C to 25.0°C. From the first law, calculate the change of internal energy of the gas in this process.

A system in a certain macrostate has 1.2 × 10³ microstates. Through some process, the system changes the number of microstates to 3 × 10⁴. What is the change in entropy for the process?

When 1.000 kg of ice melts, 33.00 × 10⁴ J/kg of heat are needed. What is the entropy change of the ice in the melting process?

What physical quantity is represented by the area under a curve on a PV diagram where pressure is in Pa and volume is in m³?

1.00 mol of oxygen gas (O₂) is heated at a constant pressure of 1.00 atm from 10.0°C to 25.0°C. How much heat is absorbed by the gas?