Chapter 18, Problem 84AP

Interpretation Introduction

Interpretation:

The equilibrium constant is greater than one, the reaction is spontaneous when all the reactants and products are in their standard states and the reaction is always exothermic for a reaction with negative $\Delta G^{\circ }$

value, are to be explained.

Concept introduction:

The quantity that predicts the spontaneity of a process is called Gibbs free energy. The mathematical equation is as follows:

$\Delta G^{\circ }=\Delta H^{\circ }-T\Delta S^{\circ }$

Here, $\Delta G^{\circ }$

is the change in standard Gibbs free energy, $\Delta H^{\circ }$ is the standard enthalpy change of a system, $\Delta S^{\circ }$

is the standard entropy change of a system, and $\text{T}$ is the absolute temperature.

Entropy is a thermodynamic function. It is the measure of randomness or disorder of the system. The unit of entropy is $\text{J/K}\text{.mol}$.

The reaction is spontaneous if $\Delta G^{\circ }$ is negative.