How IGCSE Chemistry (0620) is really marked
IGCSE Chemistry 0620 is set across theory papers (11–13, 21–23), alternative-to-practical or practical-test papers (31–33, 41–43), and practical papers (51–53, 61–63). The syllabus is overwhelmingly points-marked: 3,268 questions are points-marked against just 71 marked by calculation, so the great majority of marks are earned by giving the specific fact, name, formula or observation the mark scheme lists as acceptable — precision of wording and notation carries far more weight than working through maths.
Calculation questions are present but genuinely minor and spread thinly across papers — the largest single share is 14 on Paper 42, with most other papers carrying single-digit counts. This means candidates should not expect calculation-heavy papers; the syllabus rewards recall of chemical facts, correct equations and formulae, and accurate description of experimental procedure far more consistently than numerical work.
Practical technique still matters even outside the dedicated practical papers: naming apparatus correctly, describing observations precisely (colour, state, quantity) and giving balanced, correctly state-symbolled equations are all separately creditable points throughout the theory papers, not just on Papers 51–53 and 61–63.
Command words in IGCSE Chemistry
| Command word | Times in our bank | What it demands |
|---|---|---|
| Identify | 1258 | Name or select the specific substance, ion, structure or feature being asked about, using the correct chemical term. |
| State | 585 | Give a fact, value or observation briefly and directly, without justification. |
| Name | 213 | Give the correct specific name of a substance, piece of apparatus or process. |
| Complete | 207 | Fill in a missing entry in an equation, table or diagram, matching the format used around it. |
| Describe | 182 | Give an accurate account of what happens or what is observed, in the order it occurs. |
| Explain | 181 | Give the chemical reasoning behind an observation or trend, not just a restatement of what happens. |
| Deduce | 107 | Use the information given in the question to work out an answer that isn't stated directly — this needs reasoning from the data, not recall alone. |
| Give | 104 | State a specific answer directly, similar to State. |
How to revise with past papers
Because this syllabus is so heavily points-marked, past-paper practice is most useful when you check your wording against the mark scheme precisely — a chemically correct idea expressed with the wrong term, missing state symbol, or vague observation ('a colour change' instead of the actual colour) may not score, even though the underlying understanding is sound.
Given how small a share of the syllabus is calculation (71 questions out of the syllabus total), it's worth making sure your recall of equations, formulae and observations is rock solid before spending disproportionate revision time on maths-heavy topics — the marks are overwhelmingly there for precise chemistry, not arithmetic.
This is generic advice but worth repeating: read each command word carefully before answering. A 'Deduce' question expects you to reason from the data given in that question, not to recall a memorised fact — confusing the two commands is an easy way to miss marks that are otherwise within reach.
Practise real 0620 questions with AI marking →FAQs
How maths-heavy is IGCSE Chemistry 0620?
Not very. Only 71 questions across the whole syllabus are calculation-style, against 3,268 points-marked — recall and precise wording matter far more than numerical work.
What's the difference between 'Identify' and 'Deduce'?
Identify asks you to name something directly from knowledge; Deduce asks you to work out an answer using the specific data given in that question.
Do I need to give exact chemical terms, or is the general idea enough?
Exact terms are needed. This is a points-marked syllabus where the mark scheme lists specific acceptable wording, so vague or approximate answers often don't score even when the underlying idea is correct.
Which papers include practical skills content?
Papers 51–53 and 61–63 are the dedicated practical routes, but naming apparatus and describing observations precisely are creditable throughout the theory papers too.