Chapter 18, Problem 18.61SP

Interpretation Introduction

Interpretation:

A rough, qualitative plot of fraction of molecules versus kinetic energy for methane at $10°\text{C}$ and $100°\text{C}$ should be drawn. Also, methane gas has higher entropy at $100°\text{C}$ should be explained through plot.

Concept introduction:

The term entropy is defined as the randomness of molecules and it is represented as $S$. The entropy is state function thus entropy change only depends on the 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 the initial entropy of the system.
• $S_{\text{initial}}$ is the final entropy of the 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.