Answer:
An exergonic reaction is a chemical reaction where the change in the free energy is negative. This indicates a spontaneous reaction if the system is closed and initial and final temperatures are the same.
Formula
\Delta G=G_{\text{products }}-G_{\text{reactants }}
\Delta G = change in free energy
G_{\text{products }} = free energy of products
G_{\text{reactants }} = free energy of reactants
