Chapter 18.6, Problem 1PPC

Interpretation Introduction

Interpretation:

The graphs showing the relationship between the partial pressure of ${\text{N}}_{\text{2}}{\text{O}}_{\text{4}}$ $\left(P_{{\text{N}}_{\text{2}}{\text{O}}_{\text{4}}}\right)$ and standard free energy change $\left(\Delta G\right)$, is to be determined.

Concept introduction:

The sign of standard free energy change indicates the direction of spontaneity of the reaction.

If the free energy change is negative $\left(\Delta G^{\circ }<0\right)$, the reaction is spontaneous. It means that the formation of product is favored.

If the free energy change is positive $\left(\Delta G^{\circ }>0\right)$, the reaction is nonspontaneous. In such cases, the formation of reactant is favored.

The expression for standard Gibbs free energy change is as follows:

$\Delta G=\Delta G^{\circ }+RT\ln Q$

Here, $Q$ is the reaction quotient, $R$ is the ideal gas constant and $T$ is the temperature.