Consider a two-step mechanism carried out at 300 K
CHEMISTRY · Single correct · A Level · Chemistry · Kinetics · Kinetics
Problem
Consider a two-step mechanism carried out at 300 K.
Step A Ea = 90 kJ mol⁻¹
Step B Ea = 120 kJ mol⁻¹
The pre-exponential factors for the two steps are approximately equal. When the temperature is raised to 500 K, which statement correctly describes the relative rates of the two steps?
(a) Step B becomes faster than Step A because the larger activation energy makes it more temperature-sensitive
(b) Both steps proceed at the same rate at 500 K because the temperature increase accelerates them by the same factor
(c) Step B remains the slower step because its activation energy is still higher than that of Step A
(d) Step A becomes the slower step because the lower activation energy means it is affected less by the temperature rise