Chapter 18, Problem 48E

Interpretation Introduction

Introduction: The spontaneity of the reaction depends on the signs of enthalpy$\left(\text{Δ}H\right)$, entropy$\left(\text{Δ}S\right)$and change in free energy$\left(\text{Δ}G\right)$of the reaction. When $\text{Δ}H$and $\text{Δ}S$have opposite signs, the spontaneity of the reaction does not depend on temperature. It depends on the sign of $\text{Δ}G$. But when $\text{Δ}H$and $\text{Δ}S$have same signs, the spontaneity of the reaction depends on temperature. The effect of $\text{Δ}H$,$\text{Δ}S$and $\text{Δ}G$ on spontaneity of the reaction can be summarized as:

$\text{Δ}H$	$\text{Δ}S$	$\text{Δ}G$	Low temperature	High temperature
-	+	-	Spontaneous	Spontaneous
-	-	Temperature dependent	Spontaneous	Non spontaneous
+	+	Temperature dependent	Nonspontaneous	Spontaneous
+	-	+	Nonspontaneous	Nonspontaneous