An exothermic reaction has an uncatalyzed activation energy of 85 kJ mol⁻¹
CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
An exothermic reaction has an uncatalyzed activation energy of 85 kJ mol⁻¹. When a catalyst is added, the activation energy of the forward reaction decreases by 20 kJ mol⁻¹ and the enthalpy change remains the same. Which statement is most consistent with the catalyzed energy profile?
(a) Only the forward activation energy decreases; the reverse activation energy is unchanged, and ΔH stays the same.
(b) The activation energies for both the forward and reverse reactions decrease by 20kJ mol−1, while ΔH is unchanged.
(c) Both activation energies decrease by 20kJ mol−1, and the magnitude of ΔH also decreases by 20kJ mol−1.
(d) The energy of the transition state is unchanged, so the activation energies are identical for catalyzed and uncatalyzed pathways.