IGCSE Chemistry 0620 Exam Format Explained

Three papers decide your IGCSE Chemistry grade, and they are not equal: the theory paper alone is worth half of it. The full paper structure, timings and mark allocations are set out in the official syllabus at Cambridge International. Students who know the format plan their revision around the weightings. Students who don’t discover in April that 20% of their grade sits in a practical paper they never practised.

The two routes

Cambridge IGCSE Chemistry 0620 has two routes, and your school enters you for one of them.

Core route: Paper 1 + Paper 3 + Paper 5 or 6. Graded C to G. The best possible grade is a C, even with full marks.

Extended route: Paper 2 + Paper 4 + Paper 5 or 6. Graded A* to E. This is the route for anyone targeting an A or A*, and the route most Malaysian international schools use by default for capable students.

The content also splits. The Core syllabus is what everyone learns. The Supplement is extra material (preferential discharge in electrolysis, bond energy calculations, equilibrium, isomerism) that appears only on Papers 2 and 4. If you are still deciding routes, our Core vs Extended guide walks through the decision properly.

Every paper at a glance

Paper	Route	Format	Time	Marks	Weighting
Paper 1	Core	40 multiple-choice questions	45 min	40	30%
Paper 2	Extended	40 multiple-choice questions	45 min	40	30%
Paper 3	Core	Structured theory questions	1 h 15 min	80	50%
Paper 4	Extended	Structured theory questions	1 h 15 min	80	50%
Paper 5	Either	Practical test (in a lab)	1 h 15 min	40	20%
Paper 6	Either	Alternative to Practical (written)	1 h	40	20%

Every candidate sits exactly one paper from each row group: one MCQ, one theory, one practical assessment.

Paper 1 / Paper 2: the multiple-choice paper

Forty questions, 45 minutes, four options each. That is just over a minute per question, and the time pressure is the real examiner here.

Paper 2 questions assess the full syllabus including the Supplement, and the distractors are engineered from common errors. A typical Paper 2 mole question offers four answers: the correct one, the one you get by inverting the ratio, the one you get by forgetting to convert cm³ to dm³, and the one you get from using the wrong Mr. Guessing carries no penalty, so no question is ever left blank.

What it tests: speed of recall, careful reading, and one-step calculations. A student scoring below 30/40 on MCQ papers usually has content gaps, not technique gaps: the fix is topic revision, not more MCQ practice.

Paper 3 / Paper 4: the theory paper

Eighty marks in 75 minutes: under one minute per mark. This paper is 50% of the grade and decides it for most candidates.

Expect 6-8 structured questions, each built around a context: an industrial process, an experiment, a data table. Within one question you might name an element (1 mark), balance an equation (2 marks), calculate a mass (3 marks) and explain a trend (3 marks). Paper 4 adds Supplement content and ends questions with 4-6 mark extended responses.

A worked example of the style. A Paper 4 question on ammonia might run: state the formula of ammonia [1]; write the balanced symbol equation for its formation from nitrogen and hydrogen, N2 + 3H2 ⇌ 2NH3 [2]; explain, using ideas about equilibrium, why a higher pressure increases the yield [3]. One context, three different skills, three different command words.

What it tests: written precision. The mark scheme accepts specific phrasings and rejects loose ones: “particles have more energy” scores where “particles move more” does not.

Paper 5: the practical test

A real laboratory exam: 1 hour 15 minutes, 40 marks, usually two questions. One is typically quantitative (a titration or a rate or temperature experiment with readings to record), the other qualitative (identifying an unknown substance through a sequence of tests). Marks come from accurate readings, correct recording to the right precision, sensible graphs and valid conclusions, not from getting a “right answer”. Full detail is in our Paper 5 guide.

Paper 6: the Alternative to Practical

The same practical skills, assessed entirely on paper in 1 hour for 40 marks. You read apparatus diagrams, complete results tables, plot graphs, evaluate methods and plan experiments, all drawn from the standard 0620 experiments covered in the Experimental Techniques topic. It is the paper students most underestimate, which is exactly why we wrote a full Paper 6 guide. At 20% of the grade, it moves students a full grade in both directions.

What the weightings mean for revision

Run the numbers. Paper 4 is 50%, so one mark there is worth more revision attention than anything else. But Paper 4 is also where every student already focuses, so the marginal gains are smaller. Paper 6 is 20% of the grade with a fraction of the preparation: the typical student spends under 5% of revision time on it. That mismatch is the cheapest grade improvement in 0620.

The MCQ paper rewards broad, shallow coverage; the theory paper rewards deep technique; the practical paper rewards familiarity with about ten standard experiments. Three papers, three different kinds of preparation. A revision plan that is just “read the textbook” serves none of them.

Worked exam question

A format-awareness question students get wrong every year, from a real Paper 6 style:

The diagram shows the apparatus used to measure the volume of gas produced when calcium carbonate reacts with dilute hydrochloric acid. Name the piece of apparatus labelled X, used to collect and measure the gas. [1] Give one reason why a gas syringe gives a more accurate volume than collecting the gas over water. [1]

Model answer with mark breakdown:

• X is a gas syringe (accept: measuring cylinder inverted over water, if that is what is drawn) [1]
• Carbon dioxide is slightly soluble in water, so collecting over water loses gas and under-reads the volume [1]

The second mark is pure Paper 6 thinking: not chemistry recall, but evaluating apparatus. No amount of theory revision prepares you for it; experiment familiarity does.

The mistakes that cost marks

• Revising as if the theory paper were the whole exam. It is 50%. The other half is sat by the same student on different skills.
• Not knowing which route you are on. Core students who revise Supplement content waste weeks; Extended students who skip it cap their grade. Ask your school this week.
• Running out of time on the MCQ. Forty questions in 45 minutes punishes anyone who stalls on question 7. Flag, guess, move, return.
• Ignoring the mark allocation. A 3-mark explain needs three distinct points. One sentence under [3] is two marks donated.
• First seeing a Paper 6 in the mock. By then the table-drawing and graph habits that earn its marks should already be automatic.

How to phrase it for full marks

Format knowledge changes phrasing. On the MCQ paper there is no phrasing, only elimination. On the theory paper, match points to marks: “Explain why the rate increases [3]” needs temperature → kinetic energy → more frequent and more energetic collisions, as three separate statements. On Papers 5 and 6, write observations, not conclusions: “bubbles of gas form and the solid disappears” earns marks where “a reaction happens” earns none. Same student, same chemistry, three different writing modes.

If you want a one-session diagnosis of which paper is costing your child the most, that is exactly what our specialists do in the free 1-hour trial lesson: a real taught lesson with a past-paper question from each paper type, before any payment. No forms. WhatsApp us and we reply the same day.

The Malaysia note

Malaysian international and private schools enter candidates in May/June or October/November; most use May/June, so the exam pressure peaks alongside Year 11 farewell season. Nearly all Malaysian schools choose Paper 6 over Paper 5, because Paper 5 requires lab provisioning under exam conditions. That makes Paper 6 technique non-negotiable here, and it is the paper where we see Malaysian students lose the most recoverable marks, because school labs are used for teaching, not for exam-style write-ups. Check the weightings against your child’s mock breakdown: a strong Paper 4 with a weak Paper 6 is the most common Malaysian profile, and the easiest to fix.