Chapter 8, Problem 8.39NP

Interpretation Introduction

Interpretation:

The vapor pressure of formic acid at 298.15 K from the given standard Gibbs free energy of formation of liquid and gaseous formic acid needs to be calculated

Concept Introduction:

The standard Gibbs free energy change for a reaction ${\text{ΔG}}^{\text{0}}$ is given in terms of the difference in the standard enthalpy of formation of the products and that of reactants.

  $\Delta {\text{G}}_{\text{R}}^{\text{0}}\text{ = }{\displaystyle \sum {\text{n}}_{\text{p}}{\text{ΔG}}_{\text{f}}^{\text{0}}}\text{(products) - }{\displaystyle \sum {\text{n}}_{\text{r}}{\text{ΔG}}_{\text{f}}^{\text{0}}}\text{(reactants) ------(1)}$

The Gibbs free energy for a reaction at equilibrium is related to the equilibrium constant (K) through the Gibbs-Helmholtz isotherm:

  $\text{lnK = }\frac{-\Delta {\text{G}}_{\text{R}}^0}{\text{RT}}\text{ -----(2)}$

Where R = 8.314 J/mol-K and T is the temperature