Final answer:
At perfect equilibrium, delta G equals zero, and the equilibrium constant (K) typically equals one when all species are in their standard states. The zero value for delta G indicates that the reaction is at a state where the forward and reverse reactions occur at the same rate and no net change is observed over time.
Step-by-step explanation:
At perfect equilibrium, delta G (Gibbs free energy change) equals zero. This means that there is no net change in the composition of the reaction mixture over time and the forward and reverse reactions occur at the same rate. The equilibrium constant (K) is a ratio that quantitatively expresses the concentrations of products to reactants at equilibrium. It is calculated from the balanced equilibrium equation, reflecting the stoichiometry of the reaction.
In the related equation ΔG° = -RT ln K, R is the ideal gas constant (8.314 J/K·mol), T is the temperature in Kelvin, and K is the equilibrium constant. If ΔG is zero, rearranging the equation to solve for K would give us that ln K is also zero, indicating that K equals 1. Therefore, at equilibrium, it can be said that the equilibrium constant, K, equals one for reactions where the standard change in Gibbs free energy is zero, and all species are in their standard states.
Furthermore, the equilibrium constant is also related to the rate constants for the forward and reverse reactions; it equals the rate constant for the forward reaction divided by the rate constant for the reverse reaction. Understanding the relationship between ΔG and K is crucial for predicting the spontaneity and direction of chemical reactions as well as their equilibrium position.