Question

For the reaction 3h2(g) + n2(g) 2nh3(g), kc = 9.0 at 350°c. calculate g° at 350°c.

Answer 1

When ΔG° is the change in Gibbs free energy

So according to ΔG° formula:

ΔG° =  - R*T*(㏑K)

here when K = [NH3]^2/[N2][H2]^3 = Kc 

and Kc = 9 

and when T is the temperature in Kelvin = 350 + 273 = 623 K

and R is the universal gas constant = 8.314 1/mol.K

So by substitution in ΔG° formula:

∴ ΔG° = - 8.314 1/ mol.K * 623 K *㏑(9)

           = - 4536