Chapter 6.6, Problem 24P

Interpretation Introduction

Interpretation:

The change in molar Gibbs energy for the methane has to be determined.

Concept introduction:

Write the expression for the Gibbs energy.

$\underset{\_}{G}=\underset{\_}{H}-T\underset{\_}{S}$

Here, molar enthalpy is $\underset{\_}{H}$, temperature is T, and molar entropy is $\underset{\_}{S}$.

Write the expression for the Gibbs energy equation for entering fluid.

${\underset{\_}{G}}_1={\underset{\_}{H}}_1-T_1{\underset{\_}{S}}_1$        (1)

Write the expression for the Gibbs energy equation for exiting fluid.

${\underset{\_}{G}}_2={\underset{\_}{H}}_2-T_2{\underset{\_}{S}}_2$        (2)

Subtract the equation (1) from equation (2) to obtain the change in Gibbs energy.

${\underset{\_}{G}}_2-{\underset{\_}{G}}_1=\left({\underset{\_}{H}}_2-{\underset{\_}{H}}_1\right)-\left(T_2{\underset{\_}{S}}_2-T_1{\underset{\_}{S}}_1\right)$        (3)