CAIE A Level Chemistry 9701 · States of matter
Two sealed flasks of equal volume are at the same temperature and pressure. One flask contains an ideal gas and the other contains a real gas, ammonia. In each flask the gas exerts a pressure on the inner walls. Compare how this pressure is produced in the two flasks, and use the assumptions of the kinetic theory to explain why the ideal gas cannot be condensed to a liquid even when it is cooled, whereas ammonia can be condensed.
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.