Chapter 14.5, Problem 7PPC

Interpretation Introduction

Interpretation:

The reason why the equation $\text{ΔS }\text{}\text{=}\text{}\text{}\frac{\text{ΔΗ}}{\text{Τ}}$ is only used for phase change reaction and not for a chemical reaction 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. For all spontaneous process in an isolated system there will be an increase in entropy. Entropy is represented by the letter ‘S’.  It is a state function.  The change in entropy gives information about the magnitude and direction of a process.  The entropy changes associated with a phase transition reaction can be found by the following equation.

$\text{ΔS }\text{}\text{=}\text{}\text{}\frac{\text{ΔΗ}}{\text{Τ}}$

Where,

$\Delta {\rm H}$ is the change in enthalpy of the system

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

$\Delta \text{S}$ is the change in entropy in the system