Combined Science (A) J250,10 Higher November 2021, OCR GCSE Past Papers with Mark Schemes

1. Chemical Reactions and Stoichiometry – Calculating copper extraction yield, electrolysis of sodium chloride, and reaction rates of magnesium with acids.

2. Periodic Table and Trends – Melting and boiling points of Group 7 elements, reactivity of alkali metals, and properties of noble gases.

3. Fractional Distillation and Hydrocarbons – Crude oil separation, cracking of alkanes, and properties of different hydrocarbon fractions.

4. Environmental Chemistry and Pollution – Greenhouse gas sources, nitrogen oxides from engines, and atmospheric composition of early Earth.

5. Electrolysis and Redox Reactions – Half-equations for electrolysis, extraction of copper by displacement, and electrolysis of copper sulfate solutions.

6. Equilibrium and Reaction Conditions – Effects of temperature and pressure on equilibrium positions, Le Chatelier’s principle, and exothermic vs. endothermic reactions.