CAIE A Level Chemistry 9701 · Reaction kinetics
Hydrogen peroxide decomposes slowly at room temperature:
When a small amount of aqueous iodide ions is added, the decomposition occurs much faster.
Explain, with reference to activation energy and the Boltzmann distribution, how the iodide ions catalyse this reaction.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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