Question

Given each of the following values, is the starting material or product favored at equilibrium?

a.${\mathbf{K}}_{\mathbf{eq}}\mathbf{=}\mathbf{}\mathbf{5}\mathbf{.}\mathbf{5}$

b.${\mathbf{\Delta G}}^{\mathbf{°}}\mathbf{=}\mathbf{40}\mathbf{}\mathbf{kJ}\mathbf{/}\mathbf{mol}$

Short answer

Answer

a. The products are favored at equilibrium.

b. The starting materials are favored at equilibrium.

Step-by-step solution

Step-by-Step SolutionStep 1: Equilibrium Constant

The equilibrium constant is defined as the ratio of the reactant concentrations to the concentration of products.

${\mathrm{K}}_{\mathrm{eq}}=\frac{\left[\mathrm{products}\right]}{\left[\mathrm{reactants}\right]}$

The value of ${\mathrm{K}}_{\mathrm{eq}}>1$ indicates that the product is favored, and ${\mathrm{K}}_{\mathrm{eq}}<1$ indicates that reactants are favored.

Free energy and Chemical reactions

A chemical reaction proceeds i.e., the reactants convert into products (or the product is favored) only if the free energy change of the reaction is negative.

Direction of a chemical reaction

1. In this case, the equilibrium constant value is 5.5 i.e., ${\mathrm{K}}_{\mathrm{eq}}>1$ and hence the product is favored.
2. The free energy $\left({\mathrm{\Delta G}}^{°}\right)$ has a positive value which indicates the reaction does not proceed forward and hence it favors the starting material.