Combined Science (A) J250,10 Higher June 2018, OCR GCSE Past Papers with Mark Schemes

1. Chemical Reactions and Reactivity – Extraction of iron, dynamic equilibrium in sulfur trioxide formation, and reactivity trends in Group 7 halogens.

2. Fractional Distillation and Hydrocarbons – Separation of crude oil, alkane molecular formulas, and properties of hydrocarbons.

3. Reaction Rates and Factors – Effect of marble chip size, catalyst function, and concentration changes in reaction rates.

4. Environmental Chemistry and Climate Change – Greenhouse effect processes, CO₂ emissions, and interpreting temperature trends.

5. Periodic Table and Element Properties – Trends in alkali metals, reaction of elements with water, and comparison of melting points and densities.

6. Electrolysis and Metal Extraction – Aluminium oxide electrolysis, use of cryolite, electrode reactions, and overall balanced equations for metal production.