CAIE A Level Chemistry 9701 · Nitrogen and sulfur
A car is fitted with a catalytic converter that removes nitrogen oxides from the exhaust gases. The exhaust gases also contain unburned hydrocarbons and carbon monoxide.
Describe how the nitrogen oxides are formed in the engine, and explain how the catalytic converter removes them from the exhaust gases.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.