CAIE A Level Chemistry 9701 · Reaction kinetics
A sample of ethene, , reacts with hydrogen, , in a closed vessel at constant temperature. The pressure in the vessel is increased by forcing more hydrogen into the same volume. Explain, in terms of collisions, why the rate of reaction increases.
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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