Question

For the reaction H(g) + H₂(g) ↔ (H-H-H)^#→ H₂(g) + H(g), activation energy Ea= 23 kJ/mol and the preexponential factor A = 1.5 x 10¹⁰ L mol^-1s^-1 at 298 K. Determine ∆H^#, ∆S^#, ∆G^# and K_c^#

Answer 1

Kc^# = A .e^-Ea/RT

        = (1.5 x10^10)   x e^-23 / (8.314 x 10^-3 x 298)

        = 1.39 x 10^6 L mol^-1s^-1

∆G^#    = - R T ln Kc^#

            = -8.314 x 10^-3 x 298 x ln (1.39 x 10^6)

            = - 35 .05 kJ /mol

∆H# = Ea

         = 23 kJ /mol

∆G#   = ∆H# - T ∆S#

-35.05 x 10^3 = 23 x 10^3 - 298 x ∆S#

∆S# = 194.8 J / mol K