Thermodynamic Properties: Interactive Learning Quizzes for Engineering Mechanics

Question 1

How can the Dulong-Petit law be used to estimate the specific heat capacity of a solid?

Accepted Answer

Assuming the solid's atomic heat capacity is constant.

Answer

Measuring the temperature change of the solid during heating or cooling.

Answer

Calculating the specific heat capacity from the material's density and thermal conductivity.

Answer

Applying the Dulong-Petit law only to metals.

Question 2

The equation of state for an ideal gas describes the relationship between:

Accepted Answer

Pressure, volume, and temperature

Answer

Pressure, volume, and number of moles

Answer

Temperature, entropy, and volume

Answer

Enthalpy, internal energy, and entropy

Question 3

Entropy is a measure of:

Accepted Answer

Molecular disorder or randomness

Answer

Energy transferred as heat

Answer

Thermodynamic work done

Answer

Absolute temperature of a system

Question 4

Which of the following processes can be considered isentropic?

Accepted Answer

Adiabatic reversible process

Answer

Isothermal process

Answer

Adiabatic irreversible process

Answer

Isobaric process

Question 5

Which of the following systems is considered closed in thermodynamics?

Accepted Answer

Air sealed in a rigid container

Answer

Water evaporating from an open beaker

Answer

Steam flowing through a turbine

Answer

Ice melting in a glass cup

Question 6

The efficiency of a heat engine is determined by:

Accepted Answer

Ratio of work output to heat input

Answer

Ratio of heat input to work output

Answer

Ratio of heat rejected to work output

Answer

Ratio of work output to heat rejected

Question 7

Which equation of state is exclusively applicable to ideal gases?

Accepted Answer

Ideal gas equation

Answer

Maxwell relations

Answer

van der Waals equation

Answer

Peng-Robinson equation

Question 8

Identify the thermodynamic property that quantifies the level of disorder or randomness within a system:

Accepted Answer

Entropy

Answer

Enthalpy

Answer

Internal energy

Answer

Gibbs free energy

Question 9

In an isothermal process, the change in enthalpy is:

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Dependent on the specific path taken

Question 10

The Gibbs free energy of a system can be expressed as:

Accepted Answer

G = H - TS

Answer

G = U - TS

Answer

G = H + PV

Answer

G = U + PV

Question 11

Which factor is NOT relevant to the specific heat of a substance?

Accepted Answer

Volume

Answer

Temperature

Answer

Pressure

Answer

Material composition

Question 12

Identify the thermodynamic process characterized by constant pressure:

Accepted Answer

Isobaric

Answer

Isochoric

Answer

Isothermal

Answer

Adiabatic

Question 13

According to the Third Law of Thermodynamics, the entropy of a pure substance at absolute zero is:

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Dependent on the reference state

Question 14

What is the physical meaning of the compressibility factor in the van der Waals equation?

Accepted Answer

It shows how a real gas differs from an ideal gas.

Answer

It is a fixed value for a specific gas at a specific temperature.

Answer

It is always below 1 for real gases.

Answer

It has no practical significance.

Question 15

Which equation accurately represents the relationship between pressure (P), volume (V), and temperature (T) for an ideal gas?

Accepted Answer

PV = nRT

Answer

PV^2 = nRT

Answer

V^2P = nRT

Answer

PV = kT

Question 16

Define the specific heat at constant pressure. Identify the correct statement.

Accepted Answer

The amount of heat required to raise the temperature of 1 mole of a substance by 1 K at constant pressure

Answer

The amount of heat required to raise the temperature of 1 kg of a substance by 1 K at constant volume

Answer

The amount of heat required to raise the temperature of 1 g of a substance by 1 K at constant pressure

Answer

The amount of heat required to raise the temperature of 1 L of a substance by 1 K at constant pressure

Question 17

Entropy is a measure of which property in a system?

Accepted Answer

Degree of randomness or disorder

Answer

Temperature change

Answer

Heat transferred

Answer

Work done

Question 18

Which definition correctly describes enthalpy?

Accepted Answer

The sum of the internal energy and pressure-volume product

Answer

The difference between the internal energy and pressure-volume product

Answer

The ratio of the pressure to the volume

Answer

The product of the temperature and the entropy

Question 19

Identify the process that is isentropic.

Accepted Answer

Adiabatic reversible process

Answer

Isothermal irreversible process

Answer

Adiabatic irreversible process

Answer

Isochoric reversible process

Question 20

For an isothermal process, what is the change in internal energy of the system?

Accepted Answer

Zero

Answer

Equal to the heat transferred to the system

Answer

Equal to the work done by the system

Answer

Equal to the change in enthalpy of the system

Question 21

Which definition correctly describes the Gibbs free energy?

Accepted Answer

The change in enthalpy minus the product of temperature and entropy

Answer

The change in internal energy minus the product of temperature and entropy

Answer

The maximum work that can be done by a system at constant temperature and volume

Answer

The minimum work that must be done on a system to bring it to a given state

Question 22

Define the Helmholtz free energy. Which statement is correct?

Accepted Answer

The change in internal energy minus the product of temperature and entropy

Answer

The maximum work that can be done by a system at constant temperature and pressure

Answer

The change in enthalpy minus the product of temperature and entropy

Answer

The minimum work that must be done on a system to bring it to a given state

Question 23

Which statement best describes the van der Waals equation of state?

Accepted Answer

It enhances the ideal gas law by accounting for the volume occupied by gas molecules.

Accepted Answer

It is named after the Dutch scientist Johannes Diderik van der Waals.

Answer

It is only applicable to gases at very low temperatures.

Answer

The equation is known for its linear form.

Question 24

Which assumption of the ideal gas law is incorrect?

Accepted Answer

Gas particles have no intermolecular forces.

Answer

Gas particles have negligible volume compared to the container.

Answer

Gas particles move randomly and chaotically.

Answer

Collisions between gas particles are perfectly elastic.

Question 25

Which of the following is not considered a thermodynamic property?

Accepted Answer

Viscosity

Answer

Temperature

Answer

Pressure

Answer

Entropy

Question 26

The equation of state for an ideal gas is:

Accepted Answer

PV = nRT

Answer

PV = nRT/P

Answer

V = nRT/P

Answer

P = nRT/V

Question 27

The SI unit for specific heat is:

Accepted Answer

J/kg-K

Answer

J/kg

Answer

K/kg

Answer

J/K

Question 28

During a reversible process, the change in entropy of the system is:

Accepted Answer

dS = 0

Answer

dS > 0

Answer

dS < 0

Answer

dS = Q/T

Question 29

Which thermodynamic property measures the energy stored in a system?

Accepted Answer

Enthalpy

Answer

Entropy

Answer

Specific heat

Answer

Temperature

Question 30

Which thermodynamic process involves heat transfer at constant pressure?

Accepted Answer

Isobaric

Answer

Isochoric

Answer

Isothermal

Answer

Adiabatic

Question 31

According to the third law of thermodynamics, the entropy of a pure substance is zero at:

Accepted Answer

Absolute zero

Answer

Room temperature

Answer

Boiling point

Answer

Melting point

Question 32

Which of the following thermodynamic properties is dimensionless?

Accepted Answer

Entropy

Answer

Pressure

Answer

Temperature

Answer

Enthalpy

Question 33

The van der Waals equation of state is given by P = (RT / (V - b)) - (a / V^2). What is the primary purpose of this equation?

Accepted Answer

To account for the non-ideal behavior of gases due to molecular size and interactions

Answer

To simplify calculations for ideal gases at low pressures and high temperatures

Answer

To determine the critical temperature and pressure of a gas

Answer

To fit experimental data without a theoretical basis

Question 34

What is the SI unit of specific heat?

Accepted Answer

J/kg-K

Answer

J/kg

Answer

J/g

Answer

J/g-K

Question 35

Which of the following is a measure of the disorder of a system?

Accepted Answer

Entropy

Answer

Enthalpy

Answer

Specific heat

Answer

Internal energy

Question 36

What is the enthalpy change associated with a phase change called?

Accepted Answer

Latent heat

Answer

Sensible heat

Answer

Specific heat

Answer

Adiabatic heat

Question 37

Which of the following processes is adiabatic?

Accepted Answer

A process in which no heat is transferred

Answer

An isothermal process

Answer

A reversible process

Answer

A process in which the pressure remains constant

Question 38

What is the first law of thermodynamics?

Accepted Answer

Energy cannot be created or destroyed, but it can be transferred or transformed.

Answer

Entropy always increases.

Answer

Heat flows from hot to cold.

Answer

Pressure and volume are inversely proportional.

Question 39

What is the critical point of a substance?

Accepted Answer

The point where the liquid and gas phases become indistinguishable

Answer

The point where the solid and liquid phases become indistinguishable

Answer

The point where the solid and gas phases become indistinguishable

Answer

The point where the triple point occurs

Question 40

In the van der Waals equation of state, what do the parameters 'a' and 'b' represent?

Accepted Answer

a: intermolecular attraction, b: excluded volume

Answer

a: excluded volume, b: intermolecular attraction

Answer

a and b: excluded volume

Question 41

In a phase diagram, what is the triple point?

Accepted Answer

The point where a substance exists as a solid, liquid, and gas.

Answer

The point where a substance exists only as a solid.

Answer

The point where a substance changes from liquid to gas.

Answer

The point where a substance has the highest entropy.

Question 42

What is the most accurate definition of exergy?

Accepted Answer

The maximum useful work obtainable from a system

Answer

A constant value in any process

Answer

Applicable only to closed systems

Answer

Always positive

Question 43

Which equation of state accurately describes the behavior of an ideal gas?

Accepted Answer

PV = nRT

Answer

V/P = nRT

Answer

P/V = nRT

Answer

PV^2 = nRT^2

Question 44

State the first law of thermodynamics.

Accepted Answer

Energy cannot be created or destroyed, only transferred or transformed.

Answer

Entropy always increases in an isolated system.

Answer

Heat flows from higher to lower temperatures.

Question 45

Which of the following is not considered a thermodynamic property?

Accepted Answer

Time

Answer

Pressure

Answer

Temperature

Answer

Entropy

Question 46

Distinguish between intensive and extensive properties.

Accepted Answer

Intensive properties are independent of the amount of matter present, while extensive properties depend on the amount of matter.

Answer

Intensive properties are measurable, while extensive properties are not.

Question 47

What is the mathematical relationship between Gibbs free energy and enthalpy?

Accepted Answer

G = H - TS

Answer

G = H/T

Answer

G = H + TS

Answer

G = T(H - S)

Question 48

Which equation of state describes the relationship between pressure, volume, and temperature for a gas at constant volume?

Accepted Answer

Isochoric equation: PV = constant

Answer

Isothermal equation: PV/T = constant

Answer

Adiabatic equation: PV^γ = constant

Answer

Isobaric equation: P = constant

Question 49

The specific heat of a substance is defined as the amount of heat required to raise the temperature of 1 kg of the substance by 1 Kelvin. What is the SI unit of specific heat?

Accepted Answer

J/(kg·K)

Answer

Wh/(m³·°F)

Answer

cal/(g·K)

Answer

kJ/(kg·°C)

Question 50

What is the SI unit for entropy?

Accepted Answer

J/K

Answer

cal/(g·K)

Answer

Wh/(m³·°F)

Answer

kJ/(kg·°C)

Question 51

During an isobaric process, the change in enthalpy of a system is equal to:

Accepted Answer

The heat transferred to or from the system.

Answer

The change in internal energy of the system.

Answer

None of the above.

Answer

The work done on or by the system.

Question 52

Which thermodynamic property represents the maximum amount of useful work that can be extracted from a system at a given state?

Accepted Answer

Exergy

Answer

Enthalpy

Answer

Entropy

Answer

Specific heat

Question 53

For an ideal gas, the specific heat ratio (γ) is defined as:

Accepted Answer

The ratio of specific heats at constant pressure (Cp) and constant volume (Cv).

Answer

The ratio of volumes at constant temperature and pressure.

Answer

The ratio of pressures at constant temperature and volume.

Question 54

Which process is characterized by no heat transfer into or out of the system?

Accepted Answer

Adiabatic process

Answer

Isothermal process

Answer

Isochoric process

Question 55

The Gibbs free energy (G) of a system is defined by which equation?

Accepted Answer

G = H - TS

Answer

G = PV - U

Answer

G = H + TS

Answer

G = U + PV

Question 56

Above the critical temperature, a substance exists solely in which phase?

Accepted Answer

Gas phase

Answer

Solid phase

Answer

Plasma phase

Answer

Liquid phase

Question 57

Which of the following is NOT a reliable method for determining thermodynamic properties?

Accepted Answer

Guesswork

Answer

Experimental measurements

Answer

Use of thermodynamic tables and charts

Answer

Theoretical calculations