Cambridge IGCSE · Analysis & Prediction

2024 Cambridge IGCSE Chemistry (0620) Past Paper: Analysis & Answers

A balanced but rigorous Paper 4 (Extended) that tests key areas including stoichiometry calculation of hydrated zinc sulfate, transition metal properties, the Contact process equilibrium shifts, and organic polymer/cracking chemistry.

Updated: Jun 13, 2026

AnalysisSample paper
Difficulty 3.8/5
Total marks
160
Duration
180 mins
Most tested
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Paper breakdown

Paper 2 Multiple Choice (Extended): 40 marks · 45 minsPaper 4 Theory (Extended): 80 marks · 75 minsPaper 6 Alternative to Practical: 40 marks · 60 mins

Examiner insights

Official report

Common pitfalls

  • Forgetting to balance chemical equations, especially for non-standard reactions like the decomposition of copper(II) nitrate.
  • Omitting state symbols in ionic equations for precipitation reactions (e.g., Ba2+ and SO42- as (aq), BaSO4 as (s)).
  • Incorrectly identifying the charge on ions in zinc/copper transitions, or writing incorrect symbols for transition metal ions.
  • Omitting the single bond between oxygen and hydrogen (O-H) when drawing displayed formulae of alcohols.

Misconceptions

  • Believing that a catalyst increases the yield of a product in a reversible reaction rather than just speeding up the rate of both forward and reverse reactions.
  • Confusing sacrificial protection with barrier protection; candidates must explain that magnesium loses electrons more readily than iron, not just that it acts as a physical shield.
  • Misinterpreting the term 'solution' as a pure liquid, or failing to identify the solute and solvent parts.

Where marks are lost

  • Truncating intermediate numbers in multi-step stoichiometry calculations, resulting in rounding errors for the final value of x.
  • Providing imprecise definitions of electrolysis, such as failing to specify that the ionic compound must be molten or in aqueous solution.
  • Inability to construct correct ionic half-equations at the anode, specifically the oxidation of hydroxide ions to form oxygen and water.

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