CAIE A Level Chemistry 9701 · Nitrogen and sulfur
In a city, vehicle exhaust gases contain nitrogen monoxide and nitrogen dioxide. On a sunny day, these gases can react with unburned hydrocarbons in the air to form peroxyacetyl nitrate (PAN), a component of photochemical smog.
Suggest two conditions that favour the formation of PAN from these gases, and for each condition explain why it favours PAN formation.
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.
Suggest means: Apply what you know to an unfamiliar situation. There may be more than one acceptable answer. Reason from the principle you have learned to the new context, and say which principle you are using.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.