Thermodynamics MDCAT MCQs with Answers

The First Law of Thermodynamics is a statement of the conservation of:
a) Mass
b) Energy
c) Momentum
d) Entropy

In an isothermal process, the temperature of the system:
a) Increases
b) Decreases
c) Remains constant
d) Depends on the pressure

The Second Law of Thermodynamics states that:
a) Energy can be created and destroyed
b) Entropy of an isolated system always increases
c) Work can be completely converted into heat
d) Heat flows from a colder to a hotter body

A process that occurs at constant volume is called:
a) Isothermal
b) Isobaric
c) Isochoric
d) Adiabatic

In an adiabatic process, the heat exchange between the system and surroundings is:
a) Maximum
b) Minimum
c) Zero
d) Infinite

The internal energy of a system is a function of:
a) Temperature only
b) Pressure only
c) Volume only
d) Temperature and pressure

The enthalpy of a system is defined as:
a) H = U – PV
b) H = U + PV
c) H = U/PV
d) H = U × PV

For an ideal gas, the relationship between pressure, volume, and temperature is given by:
a) Boyle’s Law
b) Charles’s Law
c) Avogadro’s Law
d) Ideal Gas Law

The change in internal energy for a system undergoing a cyclic process is:
a) Positive
b) Negative
c) Zero
d) Dependent on work done

The efficiency of a Carnot engine is dependent on:
a) The type of working substance
b) The difference in temperatures of the reservoirs
c) The amount of heat absorbed
d) The amount of work done

The entropy change of an isolated system during a spontaneous process is:
a) Zero
b) Positive
c) Negative
d) Dependent on pressure

The Third Law of Thermodynamics states that at absolute zero, the entropy of a perfect crystal is:
a) Zero
b) Positive
c) Negative
d) Infinite

A process in which no heat is exchanged between the system and the surroundings is called:
a) Isothermal
b) Adiabatic
c) Isochoric
d) Isobaric

In an isobaric process, the pressure of the system:
a) Increases
b) Decreases
c) Remains constant
d) Is zero

The Gibbs free energy change of a reaction at constant temperature and pressure is given by:
a)
Δ
𝐺
=
Δ
𝐻
+
𝑇
Δ
𝑆
ΔG=ΔH+TΔS
b)
Δ
𝐺
=
Δ
𝐻
−
𝑇
Δ
𝑆
ΔG=ΔH−TΔS
c)
Δ
𝐺
=
Δ
𝐻
×
𝑇
Δ
𝑆
ΔG=ΔH×TΔS
d)
Δ
𝐺
=
Δ
𝐻
/
𝑇
Δ
𝑆
ΔG=ΔH/TΔS

Which of the following processes is spontaneous?
a) Heat flowing from cold to hot
b) Ice melting at room temperature
c) Gas compressing spontaneously
d) Water freezing at room temperature

The First Law of Thermodynamics can be mathematically expressed as:
a)
Δ
𝑈
=
𝑄
−
𝑊
ΔU=Q−W
b)
Δ
𝑈
=
𝑄
+
𝑊
ΔU=Q+W
c)
Δ
𝑈
=
𝑄
×
𝑊
ΔU=Q×W
d)
Δ
𝑈
=
𝑄
/
𝑊
ΔU=Q/W

For a reversible process, the entropy change of the universe is:
a) Zero
b) Positive
c) Negative
d) Infinite

The relationship between the heat added to a system, the work done by the system, and the change in internal energy is given by:
a) The First Law of Thermodynamics
b) The Second Law of Thermodynamics
c) The Third Law of Thermodynamics
d) The Zeroth Law of Thermodynamics

Which of the following is a state function?
a) Work
b) Heat
c) Entropy
d) Path length

In an isolated system, the total energy:
a) Decreases
b) Increases
c) Remains constant
d) Is zero

The concept of entropy is most closely associated with:
a) Energy conservation
b) Disorder or randomness
c) Pressure-volume work
d) Heat capacity

The maximum efficiency of a heat engine operating between two temperatures is determined by:
a) The First Law of Thermodynamics
b) The Second Law of Thermodynamics
c) The Third Law of Thermodynamics
d) Boyle’s Law

The internal energy of an ideal gas depends on:
a) Pressure only
b) Temperature only
c) Volume only
d) Pressure and volume

In an isochoric process, the work done by the gas is:
a) Positive
b) Negative
c) Zero
d) Infinite

The heat required to raise the temperature of 1 gram of a substance by 1°C is called:
a) Heat capacity
b) Specific heat
c) Latent heat
d) Enthalpy

Which of the following is an extensive property?
a) Temperature
b) Pressure
c) Volume
d) Density

Which of the following is a consequence of the Second Law of Thermodynamics?
a) Heat cannot be completely converted into work
b) Energy is conserved in an isolated system
c) Work can be done without energy input
d) Entropy decreases in a spontaneous process

The entropy of a system is a measure of its:
a) Temperature
b) Pressure
c) Disorder
d) Volume

The Zeroth Law of Thermodynamics is related to:
a) Energy conservation
b) Thermal equilibrium
c) Entropy increase
d) Heat flow

The enthalpy change of a reaction at constant pressure is equal to:
a) Work done by the system
b) Heat absorbed or released
c) Change in internal energy
d) Change in entropy

The Third Law of Thermodynamics helps in determining:
a) Absolute zero temperature
b) Zero pressure
c) Zero enthalpy
d) Zero volume

When a gas expands adiabatically, its temperature:
a) Increases
b) Decreases
c) Remains constant
d) Depends on the initial temperature

For a spontaneous process, the change in Gibbs free energy is:
a) Positive
b) Negative
c) Zero
d) Infinite

The First Law of Thermodynamics is also known as:
a) Law of Heat Exchange
b) Law of Conservation of Mass
c) Law of Conservation of Energy
d) Law of Conservation of Entropy

A Carnot engine is an example of:
a) An ideal heat engine
b) A real engine
c) A non-reversible engine
d) An engine with 100% efficiency

The relationship between entropy and probability is expressed by:
a) Maxwell’s equation
b) Planck’s law
c) Boltzmann’s equation
d) Einstein’s equation

The enthalpy of formation is defined as:
a) The heat change at constant pressure
b) The heat change at constant volume
c) The heat change when one mole of a compound is formed from its elements
d) The heat change when one mole of a substance is burned

In a thermodynamic cycle, the net work done by the system is equal to the:
a) Net heat absorbed by the system
b) Net heat released by the system
c) Change in internal energy
d) Change in entropy

Which of the following processes is associated with the maximum increase in entropy?
a) Reversible isothermal expansion
b) Reversible adiabatic expansion
c) Irreversible adiabatic expansion
d) Free expansion of a gas into a vacuum