What this practice covers
These questions are drawn from past CIE 0654 Co-ordinated Sciences papers and filtered to chemistry of the environment. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
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What examiners see students get wrong here
These are the errors that cost marks on chemistry of the environment, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Saying anhydrous copper(II) sulfate turns from blue to white when water is added. That is the test running backwards.
- Confusing the cobalt chloride and copper sulfate tests, or mixing one colour from each.
- Saying a positive water test proves the liquid is pure water. It proves only that water is present.
- Saying chlorine purifies the water supply. It makes it safe.
- Saying filtration removes dissolved impurities.
- Saying oxides of nitrogen come from nitrogen in the fuel.
- Saying sulfur dioxide comes from the air rather than from sulfur in the fuel.
- Saying a catalytic converter removes sulfur dioxide.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Chemistry of the environment revision notes.