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# Test Prep

### Multiple Choice

#### 12.1Zeroth Law of Thermodynamics: Thermal Equilibrium

1.
Which law of thermodynamics describes thermal equilibrium?
1. zeroth
2. first
3. second
4. third
2.

Name any two industries in which the principles of thermodynamics are used.

1. aerospace and information technology (IT) industries
2. industrial manufacturing and aerospace
3. mining and textile industries
4. mining and agriculture industries

#### 12.2First law of Thermodynamics: Thermal Energy and Work

3.
What is the value of the Boltzmann constant?
1. $k = 1.23 × 10 − 38 J/K$
2. $k = 1.38 × 10 − 23 J/K$
3. $k = 1.38 × 10 23 J/K$
4. $k = 1.23 × 10 38 J/K$
4.
Which of the following involves work done BY a system?
1. increasing internal energy
2. compression
3. expansion
4. cooling
5.
Which principle does the first law of thermodynamics state?
1. the ideal gas law
2. the transitive property of equality
3. the law of conservation of energy
4. the principle of thermal equilibrium
6.
What is the change in internal energy of a system when $Q in = 50 J$ and $Q out = 50 J$?
1. $20 J$
2. $30 J$
3. $50 J$
4. $70 J$
7.
When does a real gas behave like an ideal gas?
1. A real gas behaves like an ideal gas at high temperature and low pressure.
2. A real gas behaves like an ideal gas at high temperature and high pressure.
3. A real gas behaves like an ideal gas at low temperature and low pressure.
4. A real gas behaves like an ideal gas at low temperature and high pressure.

#### 12.3Second Law of Thermodynamics: Entropy

8.
In an engine, what is the unused energy converted into?
1. internal energy
2. pressure
3. work
4. heat
9.
It is natural for systems in the universe to _____ spontaneously.
1. become disordered
2. become ordered
3. produce heat
4. do work
10.
If $Q$ is $120 J$ and $T$ is $350 K$, what is the change in entropy?
1. $0.343 J/K$
2. $1.51 J/K$
3. $2.92 J/K$
4. $34.3 J/K$
11.
Why does entropy increase during a spontaneous process?
1. Entropy increases because energy always transfers spontaneously from a dispersed state to a concentrated state.
2. Entropy increases because energy always transfers spontaneously from a concentrated state to a dispersed state.
3. Entropy increases because pressure always increases spontaneoulsy.
4. Entropy increases because pressure temperature of any system always increases spontaneously.
12.

A system consists of ice melting in a glass of water. What happens to the entropy of this system?

1. The entropy of the ice decreases, while the entropy of the water cannot be predicted without more specific information.
2. The entropy of the system remains constant.
3. The entropy of the system decreases.
4. The entropy of the system increases.

#### 12.4Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators

13.
Which equation represents the net work done by a system in a cyclic process?
1. $W = Q c Q h$
2. $W = Q h + Q c$
3. $W = E f f ( Q c − Q h )$
4. $W = Q h − Q c$
14.

Which of these quantities needs to be zero for efficiency to be 100 percent?

1. ΔU
2. W
3. Qh
4. Qc
15.

Which of the following always has the greatest value in a system having 80 percent thermal efficiency?

1. ΔU
2. W
3. Qh
4. Qc
16.

In the equation Q = QhQc, what does the negative sign indicate?

1. Heat transfer of energy is always negative.
2. Heat transfer can only occur in one direction.
3. Heat is directed into the system from the surroundings outside the system.
4. Heat is directed out of the system.
17.

What is the purpose of a heat pump?

1. A heat pump uses work to transfer energy by heat from a colder environment to a warmer environment.
2. A heat pump uses work to transfer energy by heat from a warmer environment to a colder environment.
3. A heat pump does work by using heat to convey energy from a colder environment to a warmer environment.
4. A heat pump does work by using heat to convey energy from a warmer environment to a colder environment.

#### 12.1Zeroth Law of Thermodynamics: Thermal Equilibrium

18.

What does green energy development entail?

1. Green energy involves finding new ways to harness clean and renewable alternative energy sources.
2. Green energy involves finding new ways to conserve alternative energy sources.
3. Green energy involves decreasing the efficiency of nonrenewable energy resources.
4. Green energy involves finding new ways to harness nonrenewable energy resources.
19.

Why are the sun and Earth not in thermal equilibrium?

1. The mass of the sun is much greater than the mass of Earth.
2. There is a vast amount of empty space between the sun and Earth.
3. The diameter of the sun is much greater than the diameter of Earth.
4. The sun is in thermal contact with Earth.

#### 12.2First law of Thermodynamics: Thermal Energy and Work

20.

If a fixed quantity of an ideal gas is held at a constant volume, which variable relates to pressure, and what is that relation?

1. Temperature; inverse proportionality
2. Temperature, direct proportionality to square root
3. Temperature; direct proportionality
4. Temperature; direct proportionality to square $( P∝ T 2 ) ( P∝ T 2 )$
21.
When is volume directly proportional to temperature?
1. when the pressure of the gas is variable
2. when the pressure of the gas is constant
3. when the mass of the gas is variable
4. when the mass of the gas is constant
22.
For fluids, what can work be defined as?
1. pressure acting over the change in depth
2. pressure acting over the change in temperature
3. temperature acting over the change in volume
4. pressure acting over the change in volume
23.
In the equation $Δ U = Q − P Δ V$, what does $P Δ V$ indicate?
1. the work done on the system
2. the work done by the system
3. the heat into the system
4. the heat out of the system
24.

By convention, if Q is positive, what is the direction in which heat transfers energy with regard to the system?

1. The direction of the heat transfer of energy depends on the changes in W, regardless of the sign of Q.
2. The direction of Q cannot be determined from just the sign of Q.
3. The direction of net heat transfer of energy will be out of the system.
4. The direction of net heat transfer of energy will be into the system.
25.
What is net transfer of energy by heat?
1. It is the sum of all energy transfers by heat into the system.
2. It is the product of all energy transfers by heat into the system.
3. It is the sum of all energy transfers by heat into and out of the system.
4. It is the product of all energy transfers by heat into and out of the system.
26.
Three hundred ten joules of heat enter a system, after which the system does $120 J$ of work. What is the change in its internal energy? Would this amount change if the energy transferred by heat were added after the work was done instead of before?
1. $− 190 J$ ; this would change if heat added energy after the work was done
2. $190 J$; this would change if heat added energy after the work was done
3. $− 190 J$; this would not change even if heat added energy after the work was done
4. $190 J$; this would not change even if heat added energy after the work was done
27.
Ten joules are transferred by heat into a system, followed by another $20 J$. What is the change in the system’s internal energy? What would be the difference in this change if $30 J$ of energy were added by heat to the system at once?
1. $10 J$; the change in internal energy would be same even if the heat added the energy at once
2. $30 J$; the change in internal energy would be same even if the heat added the energy at once
3. $10 J$; the change in internal energy would be more if the heat added the energy at once
4. $30 J$; the change in internal energy would be more if the heat added the energy at once

#### 12.3Second Law of Thermodynamics: Entropy

28.
How does the entropy of a system depend on how the system reaches a given state?
1. Entropy depends on the change of phase of a system, but not on any other state conditions.
2. Entropy does not depend on how the final state is reached from the initial state.
3. Entropy is least when the path between the initial state and the final state is the shortest.
4. Entropy is least when the path between the initial state and the final state is the longest.
29.

Which sort of thermal energy do molecules in a solid possess?

1. electric potential energy
2. gravitational potential energy
3. translational kinetic energy
4. vibrational kinetic energy
30.
A cold object in contact with a hot one never spontaneously transfers energy by heat to the hot object. Which law describes this phenomenon?
1. the first law of thermodynamics
2. the second law of thermodynamics
3. the third law of thermodynamics
4. the zeroth law of thermodynamics
31.
How is it possible for us to transfer energy by heat from cold objects to hot ones?
1. by doing work on the system
2. by having work done by the system
3. by increasing the specific heat of the cold body
4. by increasing the specific heat of the hot body
32.

What is the change in entropy caused by melting 5.00 kg of ice at 0 °C ?

1. 0 J/K
2. 6.11×103 J/K
3. 6.11×104 J/K
4. ∞J/K
33.
What is the amount of heat required to cause a change of $35 J/K$ in the entropy of a system at $400 K$?
1. $1.1 × 10 1 J$
2. $1.1 × 10 2 J$
3. $1.4 × 10 3 J$
4. $1.4 × 10 4 J$

#### 12.4Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators

34.
In a refrigerator, what is the function of an evaporator?
1. The evaporator converts gaseous refrigerant into liquid.
2. The evaporator converts solid refrigerant into liquid.
3. The evaporator converts solid refrigerant into gas.
4. The evaporator converts liquid refrigerant into gas.
35.
Which component of an air conditioner converts gas into liquid?
1. the condenser
2. the compressor
3. the evaporator
4. the thermostat
36.

What is one example for which calculating thermal efficiency is of interest?

1. A wind turbine
2. An electric pump
3. A bicycle
4. A car engine
37.
How is the efficiency of a refrigerator or heat pump expressed?
1. $E f f = W Q c$
2. $E f f = W Q c$
3. $E f f = Q c × W$
4. $E f f = Q c W$
38.
How can you mathematically express thermal efficiency in terms of $Q h$ and $Q c$?
1. $E f f = Q h Q h − Q c$
2. $E f f = Q h Q c$
3. $E f f = Q c Q h$
4. $E f f = Q h − Q c Q h$
39.
How can you calculate percentage efficiency?
1. percentage efficiency $= ( E f f + 100 ) %$
2. percentage efficiency $= E f f 100 %$
3. percentage efficiency $= ( E f f − 100 ) %$
4. percentage efficiency $= E f f × 100 %$

### Extended Response

#### 12.1Zeroth Law of Thermodynamics: Thermal Equilibrium

40.
What is the meaning of efficiency in terms of a car engine?
1. An engine’s efficiency equals the sum of useful energy (work) and the input energy.
2. An engine’s efficiency equals the proportion of useful energy (work) to the input energy.
3. An engine’s efficiency equals the product of useful energy (work) and the input energy.
4. An engine’s efficiency equals the difference between the useful energy (work) and the input energy.

#### 12.2First law of Thermodynamics: Thermal Energy and Work

41.
Why does a bridge have expansion joints?
1. because the bridge expands and contracts with the change in temperature
2. because the bridge expands and contracts with the change in motion of objects moving on the bridge
3. because the bridge expands and contracts with the change in total load on the bridge
4. because the bridge expands and contracts with the change in magnitude of wind blowing
42.

Under which conditions will the work done by the gas in a system increase?

1. It will increase when a large amount of energy is added to the system, and that energy causes an increase in the gas’s volume, its pressure, or both.
2. It will increase when a large amount of energy is extracted from the system, and that energy causes an increase in the gas’s volume, its pressure, or both.
3. It will increase when a large amount of energy is added to the system, and that energy causes a decrease in the gas’s volume, its pressure, or both.
4. It will increase when a large amount of energy is extracted from the system, and that energy causes a decrease in the gas’s volume, its pressure, or both.
43.

How does energy transfer by heat aid in body metabolism?

1. The energy is given to the body through the work done by the body (W) and through the intake of food, which may also be considered as the work done on the body. The transfer of energy out of the body is by heat (−Q) .
2. The energy given to the body is by the intake of food, which may also be considered as the work done on the body. The transfer of energy out of the body is by heat (−Q) and the work done by the body (W) .
3. The energy given to the body is by the transfer of energy by heat (Q) into the body, which may also be considered as the work done on the body. The transfer of energy out of the body is the work done by the body (W) .
4. The energy given to the body is by the transfer of energy by heat (Q) inside the body. The transfer of energy out of the body is by the intake of food and the work done by the body (W) .
44.

Two distinct systems have the same amount of stored internal energy. Five hundred joules are added by heat to the first system, and 300 J are added by heat to the second system. What will be the change in internal energy of the first system if it does 200 J of work? How much work will the second system have to do in order to have the same internal energy?

1. 700 J ; 0 J
2. 300 J ; 300 J
3. 700 J ; 300 J
4. 300 J ; 0 J

#### 12.3Second Law of Thermodynamics: Entropy

45.
Why is it not possible to convert all available energy into work?
1. Due to the entropy of a system, some energy is always unavailable for work.
2. Due to the entropy of a system, some energy is always available for work.
3. Due to the decrease in internal energy of a system, some energy is always made unavailable for work.
4. Due to the increase in internal energy of a system, some energy is always made unavailable for work.
46.
Why does entropy increase when ice melts into water?
1. Melting converts the highly ordered solid structure into a disorderly liquid, thereby increasing entropy.
2. Melting converts the highly ordered liquid into a disorderly solid structure, thereby increasing entropy.
3. Melting converts the highly ordered solid structure into a disorderly solid structure, thereby increasing entropy.
4. Melting converts the highly ordered liquid into a disorderly liquid, thereby increasing entropy.
47.
Why is change in entropy lower for higher temperatures?
1. Increase in the disorder in the substance is low for high temperature.
2. Increase in the disorder in the substance is high for high temperature.
3. Decrease in the disorder in the substance is low for high temperature.
4. Decrease in the disorder in the substance is high for high temperature.

#### 12.4Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators

48.

In the equation W = QhQc, if the value of Qc were equal to zero, what would it signify?

1. The efficiency of the engine is 75 percent.
2. The efficiency of the engine is 25 percent.
3. The efficiency of the engine is 0 percent.
4. The efficiency of the engine is 100 percent.
49.
Can the value of thermal efficiency be greater than 1? Why or why not?
1. No, according to the first law of thermodynamics, energy output can never be more than the energy input.
2. No, according to the second law of thermodynamics, energy output can never be more than the energy input.
3. Yes, according to the first law of thermodynamics, energy output can be more than the energy input.
4. Yes, according to the second law of thermodynamics, energy output can be more than the energy input.
50.

A coal power station transfers 3.0×1012 J by heat from burning coal and transfers 1.5×1012 J by heat into the environment. What is the efficiency of the power station?

1. 0.33
2. 0.5
3. 0.66
4. 1