Chapter 15, Problem 96A

Interpretation Introduction

Interpretation:

Entropy change in the reaction is to be predicted.

Concept introduction:

Standard entropy change in a reaction can be defined as the difference of entropy change in the product and the reactants, ${\text{ΔS}}_{}^{\text{o}}$.

Answer to Problem 96A

The entropy change in the reaction ${\text{CaCO}}_{\text{3}}^{}\text{(s)}\to {\text{CaO(s)+CO}}_{\text{2}}^{}\text{(g)}$ is 160.6 j/k

Explanation of Solution

${\text{CaCO}}_{\text{3}}^{}\text{(s)}\to {\text{CaO(s)+CO}}_{\text{2}}^{}\text{(g)}$

$\begin{array}{c}{\text{ΔS}}^{\text{o}}={\displaystyle \sum {\text{nS}}_{\text{products}}^{\text{o}}-{\displaystyle \sum {\text{nS}}_{\text{reactants}}^{\text{o}}}}\\ {\text{=(1mol)[ΔS}}^{\text{o}}\text{for}{\text{CaO]+(1mol)[ΔS}}^{\text{o}}\text{for}{\text{CO}}_2\text{]}-{\text{(1mol)[ΔS}}^{\text{o}}\text{for}{\text{CacO}}_3\text{]}\\ \text{=(1mol)[39}\text{.8]+(1mol)[213}\text{.7]}-\text{(1mol)[92}\text{.9]}\\ \text{=160}\text{.6J/K}\end{array}$