CAIE A Level Chemistry 9701 · States of matter
A fixed mass of an ideal gas is sealed in a rigid container. The container is heated and the pressure of the gas increases. Explain, in terms of the behaviour of the gas molecules, why the pressure increases. In your answer, refer to the assumptions made in the ideal gas model about the size of the molecules and the forces between them.
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.