A synthetic chemist reports the following textual description of a potential-energy profile for the gas-phase isomerization of compound X to compound Y.
"Starting from the energy of the reactants as zero, the curve rises to a maximum that is 140kJmol−1 above the reactants, then drops to the products, which lie 35kJmol−1 below the reactants. In the presence of an alumina catalyst, the peak occurs at only 65kJmol−1 above the reactants; the energies of reactants and products remain unchanged."
Use this information to answer the following.
(a) Determine ΔH for the reaction and state whether the reaction is endothermic or exothermic.
(b) Calculate the difference in activation energy (ΔEa) between the uncatalyzed and catalyzed pathways.
(c) Using your answer to part (b), compute the factor by which the catalyst increases the rate constant at T=350K, assuming identical pre-exponential factors for both pathways. Express the factor as an order of magnitude (e.g., 10n) and clearly show your reasoning.