At equilibrium, the change in free energy (ΔG) is:

At equilibrium, the change in free energy (ΔG) is equal to zero. This is because, at equilibrium, the rates of the forward and reverse reactions are equal, meaning that the concentrations of the reactants and products remain constant over time.

In thermodynamic terms, the free energy change for a reaction reflects the potential to do work; when a system is at equilibrium, there is no net change in the concentrations of reactants and products, indicating that the system has reached a state of maximum entropy under the given conditions. At this point, the system is stable, and no driving force exists to proceed in either the forward or reverse direction, resulting in ΔG being zero.

This concept is foundational in understanding chemical thermodynamics and is often represented in relation to the equilibrium constant, where a reaction at equilibrium will exhibit a specific ΔG associated with the concentrations of the reactants and products. The understanding of this state is crucial for predicting the behavior of biochemical systems.