Chapter 3, Problem 3A.2E

Interpretation Introduction

Interpretation:

The change in entropy $(\Delta S)$ of water has to be determined.

Concept Information:

Spontaneous process: A process which is initiated by itself, without the help of external energy source is called spontaneous process.  All spontaneous process is associated with the decrease in free energy in the system.

Entropy is the measure of randomness in the system. The entropy change in a reaction is the difference in entropy of the products and reactants. ${\text{(ΔS}}_{\text{rxn}}\text{)}$ can be calculated by the following equation.

${\text{ΔS}}_{\text{rxn}}{\text{ = S}}_{\text{Products}}-{\text{ S}}_{\text{reactants}}$

Where,

${\text{S}}_{\text{reactants}}$ is the entropy of the reactants

${\text{S}}_{\text{Products}}$ is the standard of the products

Standard entropy change in a reaction and entropy change in the system are same.

Using the value for the change in enthalpy in a system and the temperature, we can calculate $\text{ΔS}$ for reaction of isolated system.

$\text{ΔS=}\frac{{\text{q}}_{rev}}{\text{T}}$