Free Energy and Equilibrium

        Kinetics decide if a process will go fast or slow to the equillbrium position.  Equilibrium from the thermodynamics view is the point at the lowest value of free energy available to the reacton system.  When substances undergo a chemical reaction the equilibrium is reached when the free energy is at a minimum.  This point is where G_products = G_reactants or when

                        G = G_products - G_reactants = 0

From the equation G = G° + RT ln (Q) and at equilibrium G equals 0 and Q equals K.

Then                  G = 0 = G° + RT ln (K)

or                       G° = -RT ln (K)

Qualitative Relationship between the Change in Standard Free Energy and the Equilibrium Constant for a Given Reacton

G°	K
G° = 0	K = 1
G° < 0	K > 1
G° > 0	K < 1

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