How is K_(eq) related to DeltaG^@?

1 Answer
Aug 12, 2017

If we know the equilibrium constant, K_(eq), for a chemical change we can calculate the standard state free energy change, Delta G^@.

Explanation:

The "free energy" change for a reaction may determine whether it will be spontaneous or not, but "equilibrium" is just the final state of a system. The equations may be solved either way, depending on the available data (equilibrium concentrations or energy change).

If we know the equilibrium constant, K_(eq), for a chemical change, we can calculate the standard state free energy change, DeltaG^@, for the reaction using the equation:

Delta G^@ = -RTlnK_(eq)

http://www.chem.purdue.edu/gchelp/howtosolveit/Thermodynamics/FreeEnergyChange.html

The equilibrium composition of the mixture is determined by DeltaG^@ which also defines the equilibrium constant K.
http://www.chem1.com/acad/webtext/thermeq/TE5.html