CAIE A Level Chemistry 9701 · Nitrogen and sulfur
Nitrogen gas makes up about 78% of the atmosphere. Despite this, nitrogen is often described as chemically unreactive. (a) Explain why nitrogen gas is so unreactive. (b) Ammonia, , is a weak base. Using the Brønsted–Lowry theory, explain what is meant by a weak base and describe how ammonia acts as a base when it reacts with water.
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.