Two elementary reactions, I and II

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

Problem

Two elementary reactions, I and II, have identical pre-exponential factors but different activation energies:

E_{\text{a,I}} = 35\,\text{kJ mol}^{-1}

and

E_{\text{a,II}} = 65\,\text{kJ mol}^{-1}

. When the temperature is increased from

300\,\text{K}

310\,\text{K}

, which statement is most consistent with the Maxwell–Boltzmann distribution? (a) Both reaction rates roughly double; a

10\,\text{K}

rise typically doubles reaction rates regardless of activation energy. (b) The rate of reaction I increases more because it has the lower activation energy. (c) The rate of reaction II increases by a larger factor than that of reaction I because the higher activation energy makes the rate more sensitive to temperature. (d) The rate of reaction II does not change because few particles still have enough energy to react.

Related theory

Collision Theory
Chemical Kinetics
Arrhenius Equation
Temperature Dependence of Rate

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