Calculate the equilibrium constant for the following reaction at 25 °C, given that ΔG°f(H2O(l)) = -237.2 kJ/mol and R = 8.314 J/mol•K

Question

2H₂O(l)  ⇌ 2H₂(g) + O₂(g)

Answer 1

∆G = -RT ln K

∆G = 237.2 kJ/mol (change sign for decomposition vs formation)

R = 8.314 J/Kmol = 0.008314 kJ/Kmol

T = 298K

K = ?

237.2 = -(0.008314)(298) ln K

ln K = -95.7

K = 2.74x10^-42