Entropy Principles: Identifying the True Statement

This solution identifies the correct statement regarding entropy by analyzing the properties of different states of matter.

Statement Analysis

• Option 1: Minimum entropy in equilibrium. This is incorrect. Equilibrium describes a stable state but not necessarily the state of lowest possible entropy. Minimum entropy is approached at absolute zero temperature.
• Option 2: Non-zero entropy for solid solutions at 0 K. While perfect crystals theoretically have zero entropy at absolute zero (0 K), solid solutions often possess residual entropy due to inherent disorder. However, this is a specific scenario and not the most general truth compared to other options.
• Option 3: Solid phase has the least entropy. This statement is TRUE. Entropy is a measure of randomness or disorder. In the solid phase, particles are highly ordered and possess limited motion (primarily vibrations). Liquids allow more molecular movement, and gases exhibit highly random motion, thus possessing significantly higher entropy.
• Option 4: Entropy conservation in irreversible processes. This statement is FALSE. The Second Law of Thermodynamics states that the entropy of an isolated system tends to increase over time in irreversible processes. Entropy is not conserved; it increases.

Entropy and States of Matter

The degree of molecular motion and arrangement dictates a substance's entropy. Solids, with their fixed and ordered structures, exhibit the lowest entropy. Liquids have intermediate entropy, and gases, with particles moving freely and randomly, have the highest entropy.