5070/21/M/J/25 · O Level Chemistry May/June 2025 Paper 21
8 questions, 80 marks. Each one links to its official mark scheme.
- Question 1 · 5 marks · Preparation of salts, Identification of ions and gases, Redox, Reactivity series
- Question 2 · 9 marks · Giant covalent structures, Electrolysis, Hydrogen–oxygen fuel cells
- Question 3 · 9 marks · Alkanes, Exothermic and endothermic reactions, Simple molecules and covalent bonds
- Question 4 · 12 marks · Formulae, functional groups and terminology, The mole and the Avogadro constant, The characteristic properties of acids and bases, Alcohols
- Question 5 · 12 marks · Fuels, Air quality and climate, Redox, Rate of reaction
- Question 6 · 16 marks · Solids, liquids and gases, The mole and the Avogadro constant, Redox, Reversible reactions and equilibrium, The characteristic properties of acids and bases
- Question 7 · 6 marks · Uses of metals, Reactivity series, Formulae, Oxides
- Question 8 · 11 marks · Alkenes, Carboxylic acids, Polymers, Formulae, functional groups and terminology
Questions and mark schemes from Cambridge International past papers. Paperstreak isn't affiliated with Cambridge.