Chapter 6.13, Problem 1E

To determine

Whether the irreversibility involves in the entropy production term of the entropy balance equation to the system is internal or external.

Explanation of Solution

The Second Law of Thermodynamics is defined as the of entropy of the whole universe in an isolated system will always increase with respect to time. This law explains the changes in the entropy of the universe is always positive.

The entropy balance equation is derived from the second law of thermodynamics that is specifically convenient for thermodynamic analysis.

The following expression shows the entropy balance equation.

$\Delta s=s_{in}-s_{out}+s_{gen}$

Here, the entropy change in system is $\Delta s$, the entropy coming into system is $s_{in}$, the entropy rejects from the system is $s_{out}$, and total entropy generated in the system is $s_{gen}$.

The entropy generation is positive when the internal irreversibility is present during the process and vanishes when there is no internal irreversibility.

Thus, the irreversibility involves in the entropy production term of the entropy balance equation to the system is internal.