CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
Two elementary reactions occur at 298 K. Reaction X has Ea=50kJ mol−1, and Reaction Y has Ea=100kJ mol−1. Which statement is most accurate regarding their sensitivity to a 10 K temperature increase?
(a) Both reactions speed up by roughly the same factor; rate constants are dominated by the pre-exponential term, not Ea.
(b) Reaction X speeds up proportionally more than Reaction Y because its lower activation energy makes the rate more temperature-sensitive.
(c) Reaction Y speeds up proportionally more than Reaction X because the higher activation energy makes the rate constant more sensitive to temperature.
(d) Each reaction’s rate approximately doubles for a 10 K rise around room temperature, so they experience similar fractional increases.