How to Use Past Papers Effectively for IGCSE Chemistry
The method for using IGCSE Chemistry 0620 past papers that converts practice into grade improvement. Timed conditions, marking and error logging.
Published by IGCSEChemistry.com.my
Chemistry teaching team: K. S. Tan (15+ years teaching IGCSE Chemistry) and Ms Yash (10+ years teaching IGCSE Chemistry) and Ms Kartini (15+ years teaching IGCSE Chemistry).
Mapped to Cambridge IGCSE Chemistry 0620 (2026–2028). Last updated 2026-08-19.
Past papers are the single most effective revision tool for 0620, but only when used correctly. Most students use them wrong: they sit papers untimed, check the answer to a question they are stuck on mid-paper, skim the mark scheme afterwards, and then do the next paper. This method wastes the paper and teaches nothing. The method below converts every past paper into measurable improvement.
The four-step method
Step 1: sit the paper under timed, closed-book conditions
No notes, no textbook, no phone, no checking answers partway through. Set a timer for the exact exam duration:
- Paper 2 (MCQ): 45 minutes
- Paper 4 (theory): 1 hour 15 minutes
- Paper 6 (alternative to practical): 1 hour
Work at exam pace: approximately 1 minute per mark for Papers 4 and 6. If you run out of time, draw a line under your last answer and continue, but the work below the line does not count as “completed under timed conditions.”
Step 2: mark with the official mark scheme
This is the most important step and the one most students skip or do badly.
- Use the official Cambridge mark scheme, not your teacher’s notes or a student forum answer.
- Read every mark point carefully. The scheme specifies exact wording that scores: “exothermic” earns the mark where “gives out heat” may not.
- Be honest. If your answer does not match the scheme, it does not score. Partial credit exists for method marks in calculations, but only if your working is shown.
- Circle every mark you did not earn.
Step 3: log every lost mark
In a dedicated notebook or spreadsheet, record:
| Paper | Q | Marks lost | Topic | Error type |
|---|---|---|---|---|
| Oct 2024 P4 | 3b | 1 | Acids/bases | Forgot CO2 in acid + carbonate |
| Oct 2024 P4 | 5a | 2 | Stoichiometry | Wrong Mr calculation |
| Oct 2024 P4 | 7c | 1 | Organic | Wrote “ethanol” instead of “ethanoic acid” |
After logging 3-4 papers, patterns emerge. You will see the same topics and the same error types recurring. These patterns are where your marks are.
Step 4: re-sit the failed questions one week later
Take only the questions you got wrong. Re-do them under timed conditions, without looking at the mark scheme. Then mark again.
If you get them right this time, the correction has stuck. If you get the same ones wrong again, the problem is deeper than a one-time slip and needs targeted study or help.
What to do with the patterns
After 4-5 papers, your error log will reveal your mark profile. Typical patterns:
Pattern: the same topic keeps appearing. You have a content gap. Go back to that topic, study it, do topic-sorted questions, then return to full papers.
Pattern: the same error type across topics (e.g., vague observations, missing units). You have a technique gap. Practise that technique specifically: write precise observations for 20 different reactions, or include units in every calculation answer for a week.
Pattern: running out of time on the last questions. You have a pacing problem. Practise the first 20 minutes of papers separately to build speed, and learn to skip questions that are taking too long and come back to them.
Strategic use of papers
Do not burn through all your papers at once
You have roughly 10 years of past papers available (20 sessions). Use them strategically:
- Diagnostic (1 paper): Sit early to identify weak areas. Use an older paper.
- Topic practice (topic-sorted questions): Between full papers, work on your weak topics using questions extracted by topic from multiple papers.
- Timed practice (4-6 papers): Sit under full exam conditions during the main revision period. Use mid-range papers.
- Final practice (2-3 papers): Save the most recent papers for the last 2-3 weeks. These most closely reflect current exam style.
Use the examiner reports
Cambridge publishes examiner reports for each paper series. These reports describe the common errors candidates made, what the best answers looked like, and which questions discriminated between grades. Reading the report after marking your paper tells you whether your errors are unusual or the same ones thousands of other students make (and therefore the same ones the exam will test again).
Use both May/June and October/November papers
Both series assess the same syllabus at the same difficulty level. Using both series doubles your supply of practice papers.
Common mistakes in past-paper practice
- Not timing the paper. Untimed practice creates false confidence. You may know the content but not be able to produce it fast enough.
- Checking answers mid-paper. This teaches you to rely on the mark scheme rather than your own knowledge. In the real exam, there is no mark scheme to check.
- Not marking properly. Glancing at the mark scheme and thinking “I basically got that” is not marking. Compare your answer word by word.
- Not logging errors. Without a log, the same errors repeat paper after paper without being addressed.
- Doing too many papers without analysis. Ten papers without error logging produce less improvement than five papers with thorough analysis.
More detail on past papers is in past papers, and the full revision structure is in the 8-week revision plan. If your error log reveals a persistent gap that practice alone is not closing, a trial lesson can diagnose the root cause and fix it.