A chemist studies Reaction X in both its uncatalyzed and catalyzed pathways

CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics

Problem

A chemist studies Reaction X in both its uncatalyzed and catalyzed pathways. The uncatalyzed pathway has Ea=90 kJ mol−1E_a = 90\,\text{kJ}\,\text{mol}^{-1} and ΔH=−60 kJ mol−1\Delta H = -60\,\text{kJ}\,\text{mol}^{-1}. The catalyzed pathway has Ea=40 kJ mol−1E_a = 40\,\text{kJ}\,\text{mol}^{-1} while ΔH\Delta H remains −60 kJ mol−1-60\,\text{kJ}\,\text{mol}^{-1}. Which statement best describes the effect of the catalyst on Reaction X? (a) It lowers both the activation energy and the overall enthalpy change. (b) It increases the forward reaction rate by raising the activation energy of the reverse reaction. (c) It lowers the activation energy without altering the overall enthalpy change. (d) It shifts the equilibrium toward products by lowering the energy of the products.

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