Problem 37

Question

Does the entropy of the system increase, decrease, or stay the same when (a) a solid melts, (b) a gas liquefies, (c) a solid sublimes?

Step-by-Step Solution

Verified
Answer
When a solid melts, the entropy of the system increases. When a gas liquefies, the entropy of the system decreases. When a solid sublimes, the entropy of the system increases.
1Step 1: Understand the process of melting
In the process of melting, a solid becomes a liquid. The particles in a solid are tightly packed and have a well-defined structure, while the particles in a liquid have more freedom to move around and are less structured.
2Step 2: Analyze the change in entropy
Since the particles in a liquid have more freedom to move around and are less structured, there is an increase in the number of possible energy states. This means that the entropy of the system increases.
3Step 3: Answer: Entropy increases during melting
When a solid melts, the entropy of the system increases. (B) A gas liquefies:
4Step 1: Understand the process of liquefaction
In the process of liquefaction, a gas becomes a liquid. The particles in a gas are far apart and have a lot of freedom to move around, while the particles in a liquid are relatively closer and have less freedom to move around.
5Step 2: Analyze the change in entropy
Since the particles in a liquid have less freedom to move around than in a gas, there is a decrease in the number of possible energy states. This implies that the entropy of the system decreases.
6Step 6: Answer: Entropy decreases during liquefaction
When a gas liquefies, the entropy of the system decreases. (C) A solid sublimes:
7Step 1: Understand the process of sublimation
In the process of sublimation, a solid becomes a gas without going through the liquid phase. The particles in a solid are tightly packed and have a well-defined structure, while the particles in a gas are far apart and have a lot of freedom to move around.
8Step 2: Analyze the change in entropy
Since the particles in a gas have more freedom to move around than in a solid, there is an increase in the number of possible energy states. This results in an increase in the entropy of the system.
9Step 9: Answer: Entropy increases during sublimation
When a solid sublimes, the entropy of the system increases.