Chapter 3, Problem 3.1P

(a)

Interpretation Introduction

Interpretation:

The entropy change of methane gas on expanding isothermally and reversibly has to be calculated.

Concept Information:

Change in entropy: The change in entropy when the pressure is changed from $P_i$ to $P_{\text{f}}$.

$\text{ΔS}\text{=}\text{nR}\text{ln}\left(\frac{P_{\text{f}}}{P_{\text{i}}}\right)$

Where,

‘n’ is the mole of substance,

$P_{\text{f}}$ is the final pressure of the system,

$P_i$ is the initial pressure of the system.

(b)

Interpretation Introduction

Interpretation:

The entropy change of methane gas on expanding isothermally and irreversibly has to be calculated.

Concept Information:

Change in entropy: The change in entropy when the pressure is changed from $P_i$ to $P_{\text{f}}$.

$\text{ΔS}\text{=}\text{nR}\text{ln}\left(\frac{P_{\text{f}}}{P_{\text{i}}}\right)$

Where,

‘n’ is the mole of substance,

$P_{\text{f}}$ is the final pressure of the system,

$P_i$ is the initial pressure of the system.