DP Chemistry (first assessment 2025)
Question 21M.2.HL.TZ2.b(v)
| Date | May 2021 | Marks available | [Maximum mark: 1] | Reference code | 21M.2.HL.TZ2.b(v) |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | State | Question number | b(v) | Adapted from | N/A |
b(v).
[Maximum mark: 1]
21M.2.HL.TZ2.b(v)
State how adding a catalyst to the reaction would impact the enthalpy change of reaction, ΔH, and the activation energy, Ea.
[1]
Markscheme
ΔH same AND lower Ea ✓
Syllabus sections
Reactivity 2. How much, how fast and how far? » Reactivity 2.2—How fast? The rate of chemical change » Reactivity 2.2.5—Catalysts increase the rate of reaction by providing an alternative reaction pathway with lower Ea. Sketch and explain energy profiles with and without catalysts for endothermic and exothermic reactions. Construct Maxwell–Boltzmann energy distribution curves to explain the effect of different values for Ea on the probability of successful collisions.