Potential Triangle

The three thermodynamic state functions that decide whether a reaction proceeds, and the physical quantity each pair controls: enthalpy $H$ accounts for the heat exchanged, entropy $S$ for the disorder produced, and the Gibbs free energy $G = H - TS$ combines them into the reactivity. A process runs spontaneously at fixed temperature and pressure when $G$ decreases, so raising the temperature lets an entropy gain outweigh an unfavorable enthalpy change.