5070/21/O/N/25 · O Level Chemistry October/November 2025 Paper 21
10 questions, 80 marks. Each one links to its official mark scheme.
- Question 1 · 6 marks · Naming organic compounds, Alcohols, Alkanes, Carboxylic acids, Formulae, functional groups and terminology
- Question 2 · 4 marks · Isotopes
- Question 3 · 7 marks · Exothermic and endothermic reactions, Identification of ions and gases, The mole and the Avogadro constant
- Question 4 · 9 marks · Solids, liquids and gases, Simple molecules and covalent bonds, Ion and ionic bonds, Group VII properties
- Question 5 · 10 marks · Transition elements, Metallic bonding, The mole and the Avogadro constant, Formulae, Reactivity series
- Question 6 · 9 marks · Simple molecules and covalent bonds, The mole and the Avogadro constant, Fuels, Alkenes, Formulae
- Question 7 · 13 marks · Alkenes, Rate of reaction, Reversible reactions and equilibrium, Polymers
- Question 8 · 7 marks · Formulae, functional groups and terminology, Fuels
- Question 9 · 10 marks · Preparation of salts, Water, Identification of ions and gases, Electrolysis, Ion and ionic bonds
- Question 10 · 5 marks · Air quality and climate
Questions and mark schemes from Cambridge International past papers. Paperstreak isn't affiliated with Cambridge.