### Question 1

**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.

### Question 2

**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

### Question 3

**Which phase of matter generally has the highest entropy?**

A. Solid

B. Liquid

C. Gas

D. Aqueous

### Question 4

**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.

### Question 5

**Which of the following factors does NOT affect entropy?**

A. Temperature

B. Pressure

C. Volume

D. Colour

### Question 6

**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]

### Question 7

**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]

### Question 8

**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]

### Question 9

**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]

### Question 10

**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]