Question

A reaction has a standard free-energy change of –10.90 kj mol–1 (–2.605 kcal mol–1). Calculate the equilibrium constant for the reaction at 25 °c.

Answer 1

The relation between free energy change and equilibrium constant is

ΔG = -RT ln Keq

T = 298 K

R = 8.314 J / mol K

Keq = ?

ΔG = -10.90 kJ / mole

ΔG = - 8.314 X 298 X ln Keq

ln Keq = 10900 / 8.314 X 298 = 4.4

Keq = 81.45