IGCSE Chemistry: How to Answer 6-Mark Questions — Cambridge and Edexcel 2026
The 6-mark extended writing question is where many IGCSE Chemistry students lose crucial marks — not because they don't know the chemistry, but because they don't know how to write the answer the examiner wants to see. This guide explains exactly what Cambridge (0620) and Edexcel (4CH1) examiners want. 50,000+ students since 2017 | Official British Council Partner
What Examiners Are Looking For
| Level | Marks | What It Means |
|---|---|---|
| Level 3 | 5-6 | Detailed, accurate, well-structured — all key points in logical order |
| Level 2 | 3-4 | Some detail — most points but may be incomplete or out of sequence |
| Level 1 | 1-2 | Limited — some correct chemistry but vague or missing key elements |
The 5-Step Method for Every 6-Mark Question
- Read carefully — underline key words: describe, explain, compare, evaluate
- Plan in 30 seconds — list the 5-6 points you want to make
- Use correct terminology — say "particles have greater kinetic energy and collide more frequently"
- Write in sequence — what you set up, what you do, what you observe, what you conclude
- Include what you observe — "a white precipitate forms"
Most Common 6-Mark Topics
1. Electrolysis
Identify the electrolyte, state what happens at anode and cathode, explain which ions are discharged and why, state observations, write half-equations.
2. Rates of Reaction
Independent variable, dependent variable, 3+ controlled variables, measurement method, fair test, expected observations.
3. The Haber Process
Raw materials, conditions (450°C, 200 atm, iron catalyst), why chosen (compromise between rate and yield), recycling, the equation.
4. Titration Procedure
Rinse burette, fill, record initial reading, add indicator, run alkali, swirl, approach end-point dropwise, record final reading, calculate titre. Repeat for concordant results.
Words That Get Marks vs Words That Don't
| Weak (loses marks) | Strong (gets marks) |
|---|---|
| "Particles move faster" | "Particles have greater kinetic energy" |
| "More collisions" | "More frequent successful collisions with energy ≥ activation energy" |
| "Gas comes out" | "Bubbles of colourless gas at the cathode" |
| "The solution changes colour" | "The indicator changes from colourless to pale pink at the end-point" |
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Elmadrasah.com | 50,000+ Students | IGCSE Chemistry Specialists | UAE | Since 2017
