There is no single “IGCSE Chemistry exam”. The assessment you sit depends on your syllabus code, your exam year and your route. This page shows what to confirm, where to find it, and how to prepare for the way Chemistry answers are marked.
Take paper numbers, durations, weightings and grade thresholds from the current Cambridge syllabus for your exam year. The official syllabus is the only reliable source, and reading the assessment section takes about ten minutes.
What must you confirm first?
Write down four facts and check them against your school paperwork.
- Code. Cambridge IGCSE Chemistry is 0620. Combined Science and Coordinated Sciences are separate subjects with their own codes.
- Exam year. Each syllabus applies to a range of exam years. Content and assessment details can change between ranges.
- Route. Where your syllabus shows content or papers for different routes, your school or exam centre decides which one applies to you.
- Series. Cambridge runs more than one exam series in a year. Which series you sit is decided by your exam centre, so confirm it with them.
The syllabus and exam-year navigator gives a checking list for each combination and flags fields you still need to confirm. Our 0620 qualification page explains the code in more detail.
Where do the official details live?
Open the Cambridge subject page for 0620 and download the syllabus for your exam year. The 2026 to 2028 syllabus applies only if your exam falls in that range, so check this before you use it.
In the syllabus, look for:
- the list of components (papers) and how each is assessed,
- what you may bring, including calculator rules and any data provided,
- the assessment objectives, which describe the skills the marks reward,
- the practical assessment arrangements for your route,
- the command words list, which explains terms such as “describe” and “explain”,
- whether a periodic table or data sheet is supplied in the paper.
Make a one-page summary in your own words. That page is your reference for every later decision, and it is easy to correct if your centre tells you something different.
Who is responsible for what?
| Question | Who answers it |
|---|---|
| Which syllabus and route am I entered for? | Your school or exam centre |
| Registration, entry and exam dates | Your exam centre, following Cambridge rules |
| Results and access arrangements | Your exam centre and Cambridge |
| What will I study and practise, and how? | You, with your school teacher or a private teacher |
As a tuition service, we help with the last row. Your school or exam centre enters you for exams.
How are Chemistry answers marked?
Chemistry mark schemes reward different things in different questions, and Cambridge explains the marking in the materials it publishes for your paper. Three patterns are worth practising whichever paper you sit.
Calculations reward method, accuracy and units. Take: Calculate the mass of magnesium oxide formed from 2.4 g of magnesium. (2Mg + O₂ → 2MgO; Ar: Mg = 24, O = 16.)
- Moles of Mg = 2.4 ÷ 24 = 0.10 mol.
- Ratio Mg : MgO = 2 : 2, so moles of MgO = 0.10 mol.
- Mr of MgO = 24 + 16 = 40, so mass = 0.10 × 40 = 4.0 g.
Written out, each line can earn credit. A bare “4.0” may be accepted, but it gives the marker nothing to credit if you slip.
Explanations reward a chain, not a label. “Increasing the concentration increases the rate” repeats the question. A fuller answer is: more particles in the same volume, so more frequent collisions, so more successful collisions each second. Count the links in your answer and check that each one is a reason.
Observations and conclusions are different. Write what you see, such as “a white solid forms”, separately from what you infer, such as “a carbonate is present”. Mixing them can lose a mark on both.
How should you prepare for the style of questions?
Practise three habits.
- Read the command word. “State” needs a short answer. “Explain” needs a reason. “Calculate” needs working. Underline it before you start.
- Attach units and state symbols where asked. Write “0.10 mol” and “4.0 g”, and follow the question if it asks for state symbols.
- Answer the quantity asked for. A question about moles and a question about mass need different final lines.
Use the Chemistry original practice page for questions written to practise skills, not to copy or predict an exam. For full papers, use official materials from Cambridge or your exam centre.
Where does tuition fit in?
Understanding the assessment is your responsibility with your school. Reasoning more clearly within it is where a teacher can add something.
In online one-to-one Chemistry tuition, a teacher can read how you write explanations and calculations and show you where marks are being left behind. The Chemistry learning guide sets out the topics the assessment draws on, and the revision guide shows how to turn lost marks into repairs.