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IGCSE Chemistry 0620 Paper 4 Drill Guide: Moles, Particle Explanations, Practical Design
Long answers need a mechanism, calculations need units
Paper 4 is the extended theory paper: long stems, many parts, moving from writing equations through mole calculations and experimental design to explaining trends. Losses cluster in three places: an unbalanced equation, a unit swapped mid-calculation, and an explanation that describes the observation without reaching the particle level. Circle what the part demands, then decide how many lines it needs, and write the unit beside every number.
How is IGCSE Chemistry 0620 Paper 4 assessed, and what does each part carry?
Paper 4 (Theory, Extended): Short-answer and structured, 80 marks (80 marks); Paper 2 (Multiple Choice, Extended): 40 four-choice items, 40 marks (40 marks); Paper 6 (Alternative to Practical): Practical-skills questions, 40 marks (40 marks)
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 4 (Theory, Extended) | Short-answer and structured, 80 marks | 80 marks | 1 h 15 min |
| Paper 2 (Multiple Choice, Extended) | 40 four-choice items, 40 marks | 40 marks | 45 min |
| Paper 6 (Alternative to Practical) | Practical-skills questions, 40 marks | 40 marks | 1 h |
Ten questions in 1 h 15 min is about 7 minutes each. For calculations write the formula (n = m/M, c = n/V), then substitute, then give the unit; for concepts give the definition and an example.
What each paper is actually testing
| Paper | Drill focus | How marks are lost |
|---|---|---|
| Paper 4 (Theory, Extended) | formula first for calculations, definition for concepts | The equation is unbalanced before the moles are used, so everything downstream fails. |
| Paper 2 (Multiple Choice, Extended) | eliminate the clearly wrong options | The explanation stops at the observation without reaching the particle level. |
| Paper 6 (Alternative to Practical) | accurate observation and conclusion | The practical design names no controlled variables. |
What is each IGCSE Chemistry 0620 Paper 4 paper really testing, and what should you drill?
Paper 4 (Theory, Extended): formula first for calculations, definition for concepts; Paper 2 (Multiple Choice, Extended): eliminate the clearly wrong options; Paper 6 (Alternative to Practical): accurate observation and conclusion
Drill order: by topic, then by year, then the mark scheme
| Step | What you do | Why |
|---|---|---|
| 1. By topic | Work through each topic, starting with the paper that allows least help (no calculator / closed book) | Exposes what is genuinely not understood |
| 2. By year | Whole papers to time, one or two a week | Trains pace, stamina and question selection |
| 3. Mark scheme | Go through the marking scheme question by question and log the scoring steps you missed | Most lost marks are written wrong, not thought wrong |
Should drilling go by topic first or by year?
By topic first, then whole papers by year, then the mark scheme. The first third of the time goes topic by topic (8-10 years of the same topic back to back), the middle switches to timed whole papers, and the last fortnight only redoes the recurring errors from your log.
A 12-week drilling timetable
| Week | Phase | What to do |
|---|---|---|
| Weeks 1-3 | By topic: foundation | Topic by topic, starting with the easiest marks, building habits and recall |
| Weeks 4-6 | By topic: core | 8-10 years of the same topic back to back, errors classified by topic |
| Weeks 7-8 | By topic: advanced and electives | Elective and higher-order topics, now under time pressure |
| Weeks 9-10 | By year: timed papers | One full paper a week, timed, no reference materials |
| Week 11 | Mark scheme work | Question by question against the marking scheme; list the scoring steps you omitted |
| Week 12 | Plug holes and simulate | Only the recurring errors from your log, then one full exam simulation |
Subject-specific weighting for this timetable: Weeks 1-3: ten balancing and mole items a day, units written every time. Weeks 4-6: explanation items only, forced down to the particle level, marking which sentence is observation and which is cause. Weeks 7-9: three timed papers, logging time and the parts left blank. Weeks 10-12: unseen years only, naming the variables to control beside every practical design.
Use it properly: this is not a checklist to finish. Every week must keep time for redoing errors, or from week 9 you will be repeating the same batch.
Pacing
| Paper | Time | Suggested split |
|---|---|---|
| Paper 4 (Theory, Extended) | 1 h 15 min | about 7 min per question, 5 to check |
| Paper 2 (Multiple Choice, Extended) | 45 min | about 1 min per item |
| Paper 6 (Alternative to Practical) | 1 h | read data, record, analyse |
How should the time be split inside each IGCSE Chemistry 0620 Paper 4 paper?
Paper 4 (Theory, Extended): about 7 min per question, 5 to check; Paper 2 (Multiple Choice, Extended): about 1 min per item; Paper 6 (Alternative to Practical): read data, record, analyse
The drilling mistakes that cost the most marks
| Mistake | What it looks like | What actually happens | Instead |
|---|---|---|---|
| Wrong molar mass | Taking Mg as 12 g/mol | Read the molar mass from the periodic table | Mg is 24 g/mol |
| Unbalanced equation | Writing Mg + O2 -> MgO | Balance the atoms on both sides | 2Mg + O2 -> 2MgO |
| Swapped electrodes | Chlorine at the cathode | Cathode gains the metal, anode the non-metal | Na at the cathode, Cl2 at the anode |
The error log and the mark scheme
Three columns: the part and the topic (moles, acids, organic, electrochemistry); whether the loss was an unbalanced equation, a wrong unit, an explanation stuck at the observation, an uncontrolled variable, or the clock; the repair, naming the calculation type to redo or the sentence to add. Three losses in one topic takes the next week.
How many years should you drill?
The paper arrangement and topic spread have been stable for years, so five to eight years covers the mole, acid-base, organic and electrochemical styles; some topics have changed in wording and scope, so older papers are practice only.
How many years of past papers is enough?
The paper arrangement and topic spread have been stable for years, so five to eight years covers the mole, acid-base, organic and electrochemical styles; some topics have changed in wording and scope, so older papers are practice only.
Frequently asked questions
Is this page a mock paper or a drilling guide?
This is the IGCSE Chemistry 0620 Paper 4 drilling guide: assessment structure, drill order, a 12-week timetable, pacing, common mark losses and the error-log method. For questions with answers, use the IGCSE Chemistry 0620 Paper 4 mock papers linked under Related.
By topic or by year first?
By topic. Eight to ten years of the same topic back to back is what exposes repeating errors; going straight to whole papers just repeats the same batch under time pressure.
How should the error log be written?
Do not copy out questions. Per error record four things: question reference, which step failed (concept, wording, calculation), what the mark scheme requires, and the correct action next time.
Does messy working cost marks in mole questions?
Yes. Marks are awarded per step, so write the moles, the ratio and the unit each time; the earlier marks survive even when the final answer is wrong.
How many sentences does an explanation need?
Two at least: the observation, then the particle-level reason. Trend questions usually need one more sentence saying why it happens.
Official references
| Resource | What to use it for |
|---|---|
| Cambridge IGCSE Chemistry 0620 syllabus (2026-2028) | Confirm the Paper 2/4/6 marks and times |
| https://www.tutorzone.com.hk/en-igcse-physics-0625-paper-4-mock-2027/ | IGCSE Physics (0625) Paper 4 mock |
Related: practice area · IGCSE Physics Paper 4 mock · IGCSE Chemistry Paper 6 drilling mock · IGCSE English 0500 mock
Next step: find a tutor / register as a tutor
After drilling, the hard part is telling a conceptual error from a writing error. Tell us the year group, the school and your available times, and TutorZone will match you with a tutor who knows the HKEAA assessment requirements.
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