Cambridge IGCSE Chemistry 0620 past paper practice with the mark scheme: how to use past papers so your marks actually rise
Lots of past papers and no change in the grade usually means answers are checked for being right, not marked point by point the way an examiner does. This guide covers where official 0620 past papers and mark schemes come from, a 5-step practice method, the mark-scheme abbreviations you need to read, and a chance to mark answers like an examiner.
The short answer
Official past papers and mark schemes come from Cambridge: schools that are Cambridge centres get them through the School Support Hub, and Cambridge publishes specimen papers on the 0620 syllabus page. Boom-Tutor does not host Cambridge papers; the course uses its own exam-style questions.
Past papers help most when every answer is marked point by point and you log why each mark was lost, not when you do many and look only at the total.
Past paper practice in 5 steps
| Step | Do | Why |
|---|---|---|
| 1. Real timing | Paper 4 in 1 h 15 min, Paper 6 in 1 h | Paper 4 gives less than a minute per mark; speed is part of the exam |
| 2. Mark strictly | Award only phrases that match the mark scheme | Generous self-marking means a lower real grade than you think |
| 3. Log the cause | Did not know · knew but wrote too little · misread · calculation/units | Most students lose the most marks to "knew but wrote too little" |
| 4. Rewrite lost answers | Cover the mark scheme and write a full-mark answer | Reading the answer is not practising writing it |
| 5. Review by cause | Relearn unknown topics; drill the phrases for incomplete answers | The next paper shows where the marks moved |
Mark-scheme abbreviations
The rules examiners apply on every paper are in how to answer to the mark scheme.
| In the mark scheme | Means |
|---|---|
| / (slash) | Alternatives: either one scores |
| ALLOW | Another acceptable answer, even if not the key wording |
| IGNORE | Neither gains nor loses the mark |
| NOT | This answer does not score |
| ecf | Error carried forward: a wrong value from an earlier part can still earn method marks |
| ORA | Or reverse argument: e.g. "B is slower" instead of "A is faster" |
| owtte | Or words to that effect: other wording with the same meaning |
Mark it like an examiner
Paper 4-style questions with three answers students often write. Pick one to see which marking points it earns and why. (The questions and marking points are our own, written in the style of a 0620 mark scheme, not Cambridge's.)
Explain why graphite conducts electricity. [2]
Pick the answer a student wrote and see what it scores
Marking points
- M1: delocalised (free / mobile) electrons · names what carries the charge
- M2: electrons can move (through the structure) · says that it can move
Every question marked like this on Boom-Tutor
In the course, students write their own answers and AI marks each one against the marking points, naming the missing phrase. A wrong first answer gets a hint and one more try, and timed mocks are marked the moment they are submitted (Paper 4 format · Paper 6 · 0620 tutoring).
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