0620_s26_ms_17 — 2026 May-June Chemistry 0620 Mark Scheme 1 Variant 7

0620_s26_ms_17 — 2026 May-June Chemistry 0620 Mark Scheme 1 Variant 7 · Cambridge CAIE IGCSE

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0620_s26_ms_17 — 2026 May-June Chemistry 0620 Mark Scheme 1 Variant 7

This is the official Cambridge mark scheme for Chemistry (0620) Mark Scheme 1 (Variant 7) from the 2026 May-June session. Mark schemes show exactly how each mark is awarded, including acceptable alternative answers, required key terms, and common errors that lose marks. Cambridge mark schemes use notation like "allow," "accept," and "do not credit" to define the boundary between full marks and zero.

Also referenced as: 0620_s26_ms_17 · 0620/17/m/j/26 ms · 0620/17 May/June 2026 ms

After reviewing this document, explore the other papers from this session listed below. Pairing question papers with their mark schemes is the most effective way to prepare for your exam.

Cambridge mark schemes reward precise language. For Chemistry (0620), look for keywords the examiner requires — definitions must include specific terms (e.g., "per unit mass," "resultant"), and calculations must show working even if the final answer is correct. Understanding mark scheme conventions helps you write answers that hit every marking point, not just the general idea.

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Examiner Insights — Paper 1

Based on analysis of 8 official Cambridge documents (2023, 2025)

Not reading the question stem carefully

“Candidates should take care to read each question carefully especially where chemical names are very similar such as ethane/ethene or chlorine/chloride.”— Paper 2, May/June 2025

How to fix: Before writing: (1) Underline the command word (state, explain, describe, suggest, deduce). (2) Check for 'other than' — don't repeat what's already given. (3) Check 'element' vs 'compound', 'name' vs 'formula', 'observation' vs 'conclusion'. (4) If the question says 'one reason', give exactly one — extra wrong answers cancel out correct ones.

Poor recall of qualitative tests (ion tests, gas tests, indicator colours)

“Answering of chemical test questions was poorly done, showing large gaps in the knowledge of many candidates.”— Paper 3, May/June 2023

How to fix: Make flashcards for: (1) Gas tests — hydrogen (squeaky pop), oxygen (relights splint), CO₂ (white precipitate with limewater), ammonia (damp red litmus turns blue), chlorine (damp blue litmus turns red then bleaches white). (2) Ion tests — chloride/bromide/iodide with acidified silver nitrate (white/cream/yellow precipitate), sulfate with acidified barium chloride (white precipitate). (3) Flame test colours — Li=red, Na=yellow, K=lilac, Ca=orange-red, Cu=blue-green. (4) Indicator colours — methyl orange: red in acid, yellow in alkali; phenolphthalein: colourless in acid, pink in alkali.

Confusing electrolysis products in aqueous vs molten electrolytes

“The products of the electrolysis of molten and aqueous salts were confused by many of the candidates who performed less well overall.”— Paper 2, Oct/Nov 2023

How to fix: KEY RULE: In aqueous electrolysis, reactive metals (above hydrogen in the reactivity series) are NOT discharged — hydrogen forms at the cathode instead. At the anode: if the halide is concentrated, the halogen is produced; otherwise, oxygen is produced. In MOLTEN electrolysis, the metal IS produced at the cathode because there's no water present.

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