Chapter 18, Problem 18.68SP

Interpretation Introduction

Interpretation:

The definition for second law of thermodynamics should be determined.

Concept introduction:

The entropy term is defined as randomness of molecules and it is represented as $S$. The entropy is state function thus entropy change only depends on system’s initial and final state. Entropy change of system is represented as follows:

$\Delta S=S_{\text{final}}-S_{\text{initial}}$

Where,

• $\Delta S$ is entropy change of system.
• $S_{\text{final}}$ is initial entropy of system.
• $S_{\text{initial}}$ is final entropy of system.

When randomness or entropy of system increases, the value of $\Delta S$ is positive and when randomness decreases, the value of $\Delta S$ is negative.