Chapter 18, Problem 18.81QP

Interpretation Introduction

Interpretation:

Using the value of change in entropy of the universe ${\text{(ΔS}}_{\text{univ}})$, the nature of the given process has to be explained.

Concept Introduction:

Entropy is a thermodynamic quantity, which is the measure of randomness in a system.  The term entropy is useful in explaining the spontaneity of a process.  The second law of thermodynamics says that entropy of the universe is increasing.  The change in entropy in the universe ${\text{(ΔS}}_{\text{univ}})$ is given by the summation of entropy change in the system ${\text{(ΔS}}_{\text{sys}})$ and surroundings ${\text{(ΔS}}_{\text{surr}})$.

${\text{ΔS}}_{\text{univ}}{\text{=ΔS}}_{\text{sys}}{\text{+ΔS}}_{\text{surr}}$

${\text{ΔS}}_{\text{sys}}$ associated with a phase transition reaction can be found by the following equation.

${\text{ΔS}}_{\text{sys}}\text{=}\frac{{\text{ΔΗ}}_{\text{sys}}}{\text{T}}$

Where,

  ${\text{ΔΗ}}_{\text{sys}}$ is the change in enthalpy of the system

  $\text{T}$ is the absolute value of the temperature

  ${\text{ΔS}}_{\text{surr}}$ associated with a phase transition reaction can be found by the following equation.

${\text{ΔS}}_{\text{surr}}\text{=}\frac{{\text{-ΔΗ}}_{\text{sys}}}{\text{T}}$