CAIE A Level Chemistry 9701 · Equilibria
A sealed flask contains a mixture of and at a constant temperature. The mixture is left until it reaches dynamic equilibrium:
A small amount of a solid catalyst is then added to the flask, and the mixture is left again. The temperature is kept constant throughout.
Explain, in terms of rates and concentrations, why the addition of the catalyst has no effect on the position of this equilibrium.
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.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.