Chemistry

Chemistry

Problem

Two elementary reactions of separate compounds are characterized at 298 K as follows. • Reaction 1: Ea=25 kJ mol−1E_a = 25\,\text{kJ\,mol}^{-1}, ΔG∘=−5 kJ mol−1\Delta G^{\circ} = -5\,\text{kJ\,mol}^{-1} • Reaction 2: Ea=95 kJ mol−1E_a = 95\,\text{kJ\,mol}^{-1}, ΔG∘=−40 kJ mol−1\Delta G^{\circ} = -40\,\text{kJ\,mol}^{-1} Which statement is most consistent with these data? a) Reaction 2 is more thermodynamically favorable, but Reaction 1 will occur faster; observing only the product of Reaction 1 would indicate kinetic control. b) Because Reaction 2 has the more negative ΔG∘\Delta G^{\circ}, it will both proceed faster and give the predominant product regardless of temperature. c) Increasing the temperature would favor Reaction 1 because its lower activation energy means its rate will rise more sharply than that of Reaction 2. d) If only the product of Reaction 2 is formed, the system is said to be under kinetic control because its ΔG∘\Delta G^{\circ} is more negative.

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