For diffusion of a molecule through a membrane, the activation energy can, in general, be estimated as accurately as the pre-factor D₀.

Question

Quizplus · Accepted Answer

The activation energy and the pre-factor (often related to the diffusion coefficient in the context of diffusion processes) are distinct parameters in the Arrhenius equation that describes the temperature dependence of reaction rates, including diffusion rates. The activation energy is a measure of the energy barrier that must be overcome for a reaction (or diffusion event) to occur, while the pre-factor (or frequency factor) reflects the number of attempts to cross the barrier per unit time. Estimating the activation energy from experimental data typically involves more assumptions and uncertainties compared to estimating the pre-factor, making the accuracy of their estimation differ.

For Diffusion of a Molecule Through a Membrane, the Activation