DP Chemistry (first assessment 2025)
Question 22M.1A.SL.TZ2.17
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.1A.SL.TZ2.17 |
| Level | SL | Paper | 1A | Time zone | TZ2 |
| Command term | Interpret | Question number | 17 | Adapted from | N/A |
17.
[Maximum mark: 1]
22M.1A.SL.TZ2.17
A reaction has an activation energy of 40 kJ mol−1 and an enthalpy change of −60 kJ mol−1.
Which potential energy diagram illustrates this reaction?
[1]
Markscheme
C
Examiners report
Very well answered. 82% of the candidates selected the potential energy diagram with the correct activation energy and enthalpy change to represent the reaction.
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.