How can the Gibbs energy change of a reaction relate to entropy and enthalpy?

1 Answer
Jun 16, 2017

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

Explanation:

The $\text{Gibbs Free Energy}$ includes an entropy term, and an enthalpy term. The $\text{Gibbs Free Energy}$ is the single unequivocal criterion for the spontaneity of chemical change. If $\Delta {G}^{\circ}$ $< 0$, the reaction is spontaneous; if $\Delta {G}^{\circ}$ $= 0$, the reaction is at equilibrium; If $\Delta {G}^{\circ}$ $> 0$, the reaction is non-spontaneous.

$\Delta {G}^{\circ}$ values have been tabulated for many substances, and can be used to assess many chemical reactions.........

Also, importantly, $\Delta {G}^{\circ} = - R T \ln \left\{{K}_{\text{eq}}\right\}$ (and again here $\Delta {G}^{\circ}$ must be negative to give ${K}_{\text{eq}} > 0$.