Master Thermodynamics: Online Quizzes and Learning Resources

Question 1

Simplified Expression: The correct expression for Gibbs free energy is:

Accepted Answer

G = H - TS

Answer

Removed Incorrect Option: G = U + PV

Answer

Removed Incorrect Option: G = H + TS

Answer

Removed Incorrect Option: G = U - PV

Question 2

Precise Definition: The equilibrium constant for a reaction is:

Accepted Answer

The ratio of the concentrations of reactants to products at equilibrium

Answer

The ratio of the rate constants of the forward and reverse reactions

Answer

Removed Incorrect Option: A measure of the spontaneity of the reaction

Answer

Removed Incorrect Option: Equal to the change in free energy for the reaction

Question 3

Simplified Statement: The standard molar entropy of a perfect crystal at 0 K is:

Accepted Answer

Zero

Answer

Removed Incorrect Option: Positive

Answer

Removed Incorrect Option: Negative

Answer

Removed Incorrect Option: Equal to the heat capacity of the crystal

Question 4

Simplified Question: Which of the following processes releases heat?

Accepted Answer

Combustion of methane

Answer

Removed Incorrect Option: Melting of ice

Answer

Removed Incorrect Option: Condensation of water vapour

Answer

Removed Incorrect Option: Evaporation of ethanol

Question 5

Precise Definition: The heat capacity of a substance measures:

Accepted Answer

The amount of heat required to raise its temperature by 1 degree

Answer

Removed Incorrect Option: The amount of heat required to change its phase

Answer

Removed Incorrect Option: The amount of heat required to vaporize it

Answer

Removed Incorrect Option: The amount of heat required to melt it

Question 6

Clear Distinction: Which of the following is a closed system?

Accepted Answer

A flask of water with a stopper

Answer

Removed Incorrect Option: A beaker of water open to the atmosphere

Answer

Removed Incorrect Option: A car engine

Answer

Removed Incorrect Option: A human body

Question 7

Precise Description: The Carnot cycle is a:

Accepted Answer

Theoretical heat engine that operates with maximum efficiency

Answer

Removed Incorrect Option: Practical heat engine that is used in power plants

Answer

Removed Incorrect Option: Refrigeration cycle that uses a compressor and condenser

Answer

Removed Incorrect Option: Type of chemical reaction that is reversible

Question 8

How is entropy related to the disorder of a system?

Accepted Answer

Entropy is directly proportional to the disorder of the system.

Answer

Entropy is inversely proportional to the disorder of the system.

Answer

Entropy is unrelated to the disorder of the system.

Answer

Entropy is the same as the disorder of the system.

Question 9

Explain the difference between heat and temperature.

Accepted Answer

Heat is a form of energy transfer, while temperature measures the average kinetic energy of particles.

Answer

Temperature is a form of energy transfer, while heat measures the average kinetic energy of particles.

Answer

Heat and temperature are the same physical quantity.

Answer

Heat is the potential energy of particles, while temperature is the kinetic energy of particles.

Question 10

Which of the following is a closed system in thermodynamics?

Accepted Answer

A sealed container of gas

Answer

A beaker of water with no lid

Answer

A person breathing in air

Answer

The Earth's atmosphere

Question 11

Which of the following factors does NOT affect the equilibrium constant of a gas-phase reaction?

Accepted Answer

Volume of the reaction vessel

Answer

Temperature

Answer

Pressure

Answer

Concentration of reactants

Question 12

What does the Third Law of Thermodynamics state?

Accepted Answer

The entropy of a perfect crystal at absolute zero is zero.

Answer

The entropy of a system approaches a constant value as the temperature approaches absolute zero.

Answer

The heat capacity of a system increases with decreasing temperature.

Answer

The Gibbs free energy of a system is minimized at equilibrium.

Question 13

According to the Third Law of Thermodynamics, what occurs to the entropy of a perfect crystal at absolute zero?

Accepted Answer

It becomes zero.

Answer

It becomes infinite.

Answer

It remains constant.

Answer

It becomes negative.

Question 14

Which statement accurately reflects the Second Law of Thermodynamics?

Accepted Answer

Entropy of an isolated system always increases over time.

Answer

Heat flows spontaneously from hot to cold bodies.

Answer

The total energy of the universe is constant.

Question 15

What is the entropy (ΔS) change for the isothermal expansion of an ideal gas?

Accepted Answer

Positive and can be calculated as nR*ln(V2/V1)

Answer

Zero.

Answer

Negative and can be calculated as nR*ln(V1/V2)

Answer

Cannot be determined without additional information.

Question 16

Which of the following is a closed system?

Accepted Answer

A sealed container containing a gaseous reaction

Answer

A lake exposed to the atmosphere

Answer

A room with an open window

Question 17

According to the Third Law of Thermodynamics, what is the entropy of a perfect crystal at absolute zero?

Accepted Answer

Zero

Answer

Indeterminate

Answer

Positive

Answer

Negative

Question 18

Which of the following is the first law of thermodynamics?

Accepted Answer

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

Answer

Entropy always increases in isolated systems.

Answer

Heat is a form of energy that can be transferred.

Question 19

What is the difference between enthalpy (H) and entropy (S)?

Accepted Answer

Enthalpy is a state function that measures the total thermal energy of a system, while entropy is a state function that measures the degree of disorder or randomness of a system.

Answer

Enthalpy is a measure of heat flow, while entropy is a measure of heat capacity.

Question 20

What is the Gibbs free energy?

Accepted Answer

A thermodynamic potential that determines the maximum amount of non-expansion work that can be extracted from a thermodynamic system at constant temperature and pressure.

Answer

A measure of the total thermal energy of a system

Question 21

Which of the following is a spontaneous process?

Accepted Answer

The dissolution of salt in water

Answer

The boiling of water at room temperature

Answer

The formation of ice at room temperature

Answer

The electrolysis of water

Question 22

What is the standard enthalpy change of formation?

Accepted Answer

The enthalpy change that occurs when one mole of a substance is formed from its constituent elements in their standard states.

Answer

The enthalpy change that occurs when one mole of a substance is burned in oxygen

Question 23

What is the relationship between the equilibrium constant and the standard free energy change?

Accepted Answer

The equilibrium constant is directly proportional to the exponential of the negative standard free energy change.

Answer

The equilibrium constant is inversely proportional to the standard free energy change

Question 24

What is the third law of thermodynamics?

Accepted Answer

The entropy of a perfect crystal vanishes as the temperature approaches absolute zero.

Answer

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

Answer

Heat cannot spontaneously flow from a colder reservoir to a hotter reservoir

Question 25

What is the Carnot cycle?

Accepted Answer

A theoretical heat engine that operates reversibly and has the highest possible efficiency between two fixed temperatures.

Answer

A type of heat engine that uses electricity to generate power

Answer

A type of heat engine that uses solar energy to generate power

Question 26

What is the Joule-Thomson effect?

Accepted Answer

The change in temperature of a gas when it undergoes a throttling process (i.e., expansion through a valve or porous plug).

Answer

The change in pressure of a gas when it undergoes a throttling process

Answer

The change in volume of a gas when it undergoes a throttling process