# How does delta G affect keq?

The change in Gibbs Free Energy ($\Delta G$) for any reaction is related to the equilibrium constant ${K}_{e q}$ by the simple equation:
$\Delta G = - R T \ln {K}_{e q}$
where $R$ is the universal gas constant, 8.314 J/mol-K and $T$ is the temperature of the system in Kelvins.
If $\Delta G$ is negative, then $K > 1$, which means that the reaction will be spontaneous in the forward direction when all species are present in standard concentrations (1 bar for gases, 1 M for solutes).
If $\Delta G > 0$ then the reverse reaction is spontaneous from standard conditions.