Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can explain the two ways a catalyst raises the rate: more favourable orientation and a new path with a lower activation energy. (Guide: “What a catalyst does”; Practice Q1, Q7)
- I can explain why a catalyst is not used up overall even though it takes part in the mechanism. (Guide: “Catalysts in a mechanism”; Practice Q5(d))
- I can state what a catalyst does not change: ΔH and the energies of the reactants and products. (Guide: Figure 1; Practice Q1)
- I can describe how enzyme, acid–base and surface catalysts each create new intermediates and new elementary steps. (Guide: “Three ways catalysts work”; Practice Q5, Q6, Q7)
Skills
- I can identify the catalyst and the intermediates in a proposed mechanism and check that the steps add up. (Guide: Worked example 1; Practice Q2, Q5(a))
- I can use initial-rate data to show that a catalyst appears in the rate law, and calculate k with units. (Practice Q4)
- I can write a mechanism in which the catalyst is consumed in the slow step and regenerated later. (Practice Q4(c))
- I can calculate forward and reverse barriers for catalysed and uncatalysed paths from an energy profile. (Guide: Worked example 2; Practice Q3)
- I can sketch or describe a catalysed energy profile with extra humps and a dip for the new intermediate. (Guide: Figure 1; Practice Q7(c))
Reasoning
- I can use a collision-energy distribution to explain why a lower barrier gives a faster rate at the same temperature. (Guide: Figure 2; Practice Q7(a))
- I can explain why a powdered surface catalyst works faster than a lump of the same mass. (Practice Q6(c))
- I can evaluate a claim about a catalyst using particle-level evidence, not just the overall equation. (Practice Q5(d), Q6(d), Q7(a))
All ticked? Unit 5 is complete. Move on to Topic 6.1, Endothermic and Exothermic Processes, or return to the course roadmap.