Question

During a heat transfer process, the entropy of a system (always, sometimes, never) increases.

Short answer

Answer: Sometimes.

Step-by-step solution

1. Understanding Entropy

Entropy is a thermodynamic property that measures the amount of thermal energy unavailable to do useful work in a system. It is often associated with the randomness or chaos in a system. The second law of thermodynamics states that the total entropy of an isolated system can only increase over time or, in the case of a reversible process, remain constant.

2. Reversible and Irreversible Processes

In thermodynamics, processes can be classified as reversible or irreversible. A reversible process is an ideal process, which is assumed to occur very slowly and infinitely close to equilibrium. In a reversible process, the entropy of a system remains constant, and no energy is lost as waste. However, real-life processes are always irreversible, as they involve some mechanical, heat, or viscous losses. In an irreversible process, the entropy of a system increases.

3. Entropy Change During Heat Transfer

During a heat transfer process, the entropy change depends on the nature of the process. If it is a reversible process, the entropy of the system remains constant as the heat is transferred evenly, and no energy is lost to the surroundings. However, in most real-life situations, the processes are irreversible, and energy is lost as waste due to mechanical, heat, or viscous losses. In this case, the entropy of the system increases during the heat transfer process. So, based on the above discussion:

Conclusion

The entropy of a system increases "sometimes" during a heat transfer process. It remains constant in the ideal, reversible processes, but increases in real-life, irreversible processes.