What this practice covers
These questions are drawn from past CIE 0654 Co-ordinated Sciences papers and filtered to experimental techniques and chemical analysis. 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 experimental techniques and chemical analysis, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Using crystallisation or distillation to remove an insoluble impurity, when only filtration can.
- Crystallising before filtering, so the impurity ends up in the crystals.
- Saying filtration removes dissolved substances.
- Confusing the lighted splint and the glowing splint tests.
- Drawing the chromatography baseline in ink.
- Starting the chromatogram with the baseline below the solvent level.
- Calculating Rf as solvent distance divided by spot distance, giving an answer above 1.
- Swapping lithium and sodium flame colours.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Experimental techniques and chemical analysis revision notes.