The standard state Gibb's free energies of formation of C (graphite) and C (diamond) at T = 298 K are Δ f G o C ( graphite = 0 kJ mol - 1 Δ f G o C diamond = 2 .9 kJ mol - 1 The standard state means that the pressure should be 1 bar, and substance should be pure at a given temperature. The conversion of graphite [ C (graphite)] to diamond [ C (diamond)] reduces its volume by 2 × 10 - 6 m 3 mol - 1

Step-by-step solution

C graphite → C diamond ;   ΔG o = Δ f G diamond o - Δ f G graphite o = 2 .9   kJ / mol at 1 bar As dG T = V . dP ∫ ΔG 1 ΔG 2 d ΔG T =   ∫ P 1 P 2 ΔV . dP ΔG 2 - ΔG 1 = ΔV .   P 2 - P 1 2 .9 × 10 3 - 0 = - 2 × 10 - 6   1 - P 2 P 2 - 1 = 2 .9 × 10 3 2 × 10 - 6 Pa = 1 .45 × 10 4   bar P 2 = 14501    bar .