Chapter 5, Problem 5.9NP

(a)

Interpretation Introduction

Interpretation: The value of change in entropy, change in total entropy and change in entropy of surrounding for an adiabatic reversible expansion needs to be calculated. Whether the process is spontaneous or not needs to be determined.

Concept Introduction:

The change in entropy can be calculated as follows:

  $\Delta S={\displaystyle \int \frac{d{q}_{\text{reversible}}}{T}}$

Here, $\Delta S$ is change in entropy, $q_{\text{reversible}}$ heat for reversible process and T is temperature.

(b)

Interpretation Introduction

Interpretation: The value of change in entropy, change in total entropy and change in entropy of surrounding for an expansion against external pressure equal to zero needs to be determined. Whether the process is spontaneous or not needs to be determined.

Concept Introduction: The change in entropy for an adiabatic expansion can be calculated as follows:

  $\Delta S=nR\ln \frac{V_f}{V_i}+n{C}_{P,m}\ln \frac{T_f}{T_i}$

Here, $\Delta S$ is change in entropy, n is number of moles, R is Universal gas constant, V is volume and $C_{P,m}$ is heat capacity at constant pressure and T is temperature.

(c)

Interpretation Introduction

Interpretation: The value of change in entropy, change in total entropy and change in entropy of surrounding for an isothermal reversible expansion needs to be determined. Whether the process is spontaneous or not needs to be determined.

Concept Introduction: The change in entropy for can be calculated as follows:

  $\Delta S=nR\ln \frac{V_f}{V_i}+n{C}_{P,m}\ln \frac{T_f}{T_i}$

Here, $\Delta S$ is change in entropy, n is number of moles, R is Universal gas constant, V is volume and $C_{P,m}$ is heat capacity at constant pressure and T is temperature.