Which of the following best describes entropy?

A. The measure of energy in a system.

B. The measure of disorder or randomness in a system.

C. The measure of heat transfer in a system.

D. The measure of work done by a system.

What is the unit of entropy in the International System of Units (SI)?

A. Joule

B. Kelvin

C. Joule per Kelvin

D. Kelvin per Joule

Which phase of matter generally has the highest entropy?

A. Solid

B. Liquid

C. Gas

D. Aqueous

If a reaction results in an increase in the number of gaseous molecules, what can be said about the change in entropy?

A. Entropy decreases.

B. Entropy remains unchanged.

C. Entropy increases.

D. Cannot be determined without additional information.

Which of the following factors does NOT affect entropy?

A. Temperature

B. Pressure

C. Volume

D. Colour

a) Define entropy (S) in thermodynamics and explain its relationship to the degree of disorder in a system. [3]

b) Calculate the change in entropy (ΔS) when 2 moles of ice (H2O(s)) at -10°C are melted to form 2 moles of water (H2O(l)) at 20°C. Given ΔHfus° = 6.01 kJ/mol and ΔSfus° = 22.0 J/(mol·K). [2]

a) Explain the concept of microstates in thermodynamics and how it is related to entropy (S). [3]

b) Calculate the change in entropy (ΔS) when 1 mole of nitrogen gas (N2(g)) at 25°C and 1 atm pressure is allowed to expand irreversibly into a vacuum until its volume doubles. Assume ideal behaviour. [2]

a) Describe the role of temperature in the spontaneity of chemical reactions according to Gibbs free energy (ΔG). [3]

b) Calculate the change in entropy (ΔS) when 2 moles of chlorine gas (Cl2(g)) at 100°C and 2 atm pressure are compressed to 1 mole of chlorine gas at the same temperature and pressure. Assume ideal behaviour. [2]

a) Define entropy (S) in thermodynamics and explain how it relates to the dispersal of energy. [3]

b) Calculate the change in entropy (ΔS) when 1 mole of a monoatomic ideal gas undergoes an isothermal expansion at 298 K, doubling its volume. [2]

c) Discuss the factors that affect the spontaneity of a chemical reaction based on changes in entropy. [3]

a) Explain the concept of microstates in thermodynamics and how it is related to entropy (S). [3]

b) Calculate the change in entropy (ΔS) when 1 mole of water (H2O) freezes at its standard freezing point, assuming ideal behaviour. Given ΔHfus° = 6.01 kJ/mol. [3]

c) Discuss the significance of the sign of ΔS in determining whether a process is spontaneous or non-spontaneous. [2]

What is the Gibbs equation used to predict?

A. The spontaneity of a reaction.

B. The heat capacity of a substance.

C. The bond energy of molecules.

D. The rate of a reaction.

For a reaction to be spontaneous at all temperatures, which of the following conditions must be met?

A. Δh > 0 and Δs > 0

B. Δh < 0 and Δs > 0

C. Δh > 0 and Δs < 0

D. Δh < 0 and Δs < 0

If the Gibbs free energy (Δg) of a reaction is positive, what can be inferred about the reaction?

A. The reaction is spontaneous.

B. The reaction is non-spontaneous.

C. The reaction is at equilibrium.

D. The reaction rate is high.

How does an increase in temperature generally affect the entropy of a system?

A. Decreases the entropy.

B. Increases the entropy.

C. Does not affect the entropy.

D. Makes the entropy zero.

Which of the following is NOT a factor that would increase the entropy of a system?

A. Dissolving a solid in water.

B. Compressing a gas into a smaller volume.

C. Heating a liquid.

D. Evaporating a liquid.

a) Describe the relationship between temperature and the spontaneity of a chemical reaction according to Gibbs free energy (ΔG). [3]

b) Calculate the change in entropy (ΔS) when 2 moles of solid potassium iodide (KI) dissolve in water to form a saturated solution at 25°C. Given Ksp = 6.6 x 10^-7 at this temperature. [3]

c) Explain how changes in pressure and volume affect the entropy of a gas. [2]

a) Explain the concept of the standard molar entropy (S°) and how it relates to the entropy change in chemical reactions. [3]

b) Calculate the change in entropy (ΔS) when 1 mole of solid sodium chloride (NaCl) at 25°C is dissolved in 1 litre of water to form a saturated solution. Given ΔS° for NaCl dissolution is 72.1 J/(mol·K). [3]

c) Discuss the concept of "spontaneous processes" in the context of thermodynamics and the role of entropy in determining spontaneity. [2]

a) Explain how the second law of thermodynamics relates to the concept of entropy and the direction of natural processes. [3]

b) Calculate the change in entropy (ΔS) when 1 mole of an ideal gas undergoes an adiabatic expansion at 300 K, doubling its volume. [2]

c) Describe the conditions under which a spontaneous process can have a negative change in entropy (ΔS < 0). Provide an example. [3]

d) Discuss the role of entropy in predicting whether a chemical reaction will proceed to the right or to the left, given the equilibrium constant (K). [2]

a) Define the standard entropy change (ΔS°) and explain how it is related to the standard Gibbs free energy change (ΔG°) for a chemical reaction. [3]

b) Calculate the change in entropy (ΔS) when 2 moles of ammonia (NH3) gas are compressed isothermally from 2 litres to 1 litre at 25°C. Given ΔH° = -45.9 kJ/mol for this process. [3]

c) Discuss the concept of "entropy of mixing" and its relevance in solutions. Provide an example to illustrate. [2]

d) Explain how the entropy change of the surroundings (ΔSuniverse) relates to the spontaneity of a process. [2]

a) Explain the concept of absolute entropy and how it is determined for chemical substances. [3]

b) Calculate the change in entropy (ΔS) when 1 mole of liquid water at 373 K is vaporised to form 1 mole of steam at the same temperature. Given ΔHvap° = 40.7 kJ/mol for this process. [3]

c) Discuss the relationship between the spontaneity of a process and the sign of ΔG, considering both ΔH and ΔS values. Provide examples. [2]

d) Describe the role of entropy in phase transitions, such as melting, boiling, and freezing, and how it affects the Gibbs free energy. [2]