Reactions X and Y occur in the gas phase and have identical collision frequencies and…
CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
Reactions X and Y occur in the gas phase and have identical collision frequencies and orientation factors.
X: Ea=75kJ mol−1
Y: Ea=60kJ mol−1
The temperature of the reaction vessel is increased from 300 K to 310 K. Which statement best predicts how the rate constants of the two reactions change?
(a) Both rate constants increase by exactly the same factor because their pre-exponential terms are identical.
(b) The rate constant of Y rises by a larger factor than that of X since a lower activation energy makes the reaction more responsive to temperature.
(c) The rate constant of X rises by a larger factor than that of Y because a higher activation energy makes the rate more temperature-sensitive.
(d) Both rate constants increase, but X rises by about 12% whereas Y rises by roughly 15%, so Y increases slightly more.