For the gas-phase decomposition reaction
E(g) → F(g)
the following data have been obtained at a particular temperature:
• Activation energy for the reverse reaction (F → E): 130 kJ mol⁻¹
• Overall energy change, ΔE (E → F): –60 kJ mol⁻¹
A newly discovered homogeneous catalyst lowers the activation energy of the forward reaction by 45 kJ mol⁻¹ but does not change the energies of the reactants, products, or transition state for the reverse reaction.
(a) Determine the activation energy for the forward reaction in the absence of the catalyst. Show your reasoning.
(b) Calculate the activation energy for the forward reaction in the presence of the catalyst.
(c) On a single set of axes, construct a reaction energy profile that includes (i) the uncatalyzed pathway and (ii) the catalyzed pathway. Label each curve, the respective transition states, reactants, products, Eₐ (forward) for both pathways, Eₐ (reverse), and ΔE.
(d) Explain, with reference to your diagram and calculated values, whether the catalyst would be expected to alter the equilibrium constant of the reaction. Justify your answer.