Question

Enter your answer in the provided box. In the Mond process for the purification of nickel, carbon monoxide is reacted with heated nickel to produce Ni(CO)4, which is a gas and can therefore be separated from solid impurities: Ni(s) + 4CO(g) Ni(CO)_4(g) Given that the standard free energies of formation of CO(g) and Ni(CO)_4(g) are -137.3 and -587.4 kJ/moI, respectively, calculate the equilibrium constant of the reaction at 76.0 degree C. Assume that Delta G f is temperature-independent.

Answer 1

Answer – We are given, reaction – Ni(s) + 4CO(g) <----> Ni(CO)₄(g)

ΔG^o_f Ni(CO)₄(g) = -587.4 kJ/mol , ΔG^o_f CO(g) = -137.3 kJ/mol , T = 76+273 = 349 K

Now we need to calculate the ΔG^o_rxn

We know formula

ΔG^o_rxn = sum of the ΔG^o_f product - sum of the ΔG^o_f reactant

So, ΔG^o_rxn = [ΔG^o_f Ni(CO)₄(g)] – [4* ΔG^o_f CO(g)]

ΔG^o_rxn = (-587.4 kJ/mol) – ( 4*-137.3 kJ/mol)

           = (-587.4 kJ/mol) – (-549.2)

           = -38.2 kJ/mol

            = -3.82*10⁴ J/mol

Now we know the formula for calculating the equilibrium constant form the standard free energy.

ΔG^o_rxn = -RT*lnK

-3.82*10⁴ J/mol = - 8.314 J/mol.K * 349 K * ln K

ln K = -3.82*10⁴ J/mol / - 8.314 J/mol.K * 349 K

       = 13.16

So, taking anitln form both side

K = 5.19*10⁵