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WalesCombined Science

Unit 5 Chemistry 2: Organic and industrial chemistry

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What are alkanes and alkenes, and why is cracking used?

Alkanes and alkenes, the test for an alkene, the combustion of hydrocarbons, and cracking to make smaller useful molecules.
A focused answer to the WJEC GCSE Science Double Award Unit 5 topic on organic chemistry, covering alkanes and alkenes and the bromine-water test, the combustion of hydrocarbons, and cracking to make smaller, more useful molecules.
9 min answer →

What is crude oil, and how is it separated into useful fractions?

Crude oil as a mixture of hydrocarbons, fractional distillation, and the properties and uses of the fractions.
A focused answer to the WJEC GCSE Science Double Award Unit 5 topic on crude oil, covering crude oil as a mixture of hydrocarbons, how fractional distillation separates it, and the properties and uses of the fractions.
9 min answer →

What is a reversible reaction, and what does equilibrium mean?

Reversible reactions, the symbol used, energy changes in reversible reactions, and the idea of a dynamic equilibrium in a closed system.
A focused answer to the WJEC GCSE Science Double Award Unit 5 topic on reversible reactions, covering what a reversible reaction is and its symbol, the energy changes in each direction, and the idea of a dynamic equilibrium in a closed system.
9 min answer →

How is ammonia made in the Haber process, and why are the conditions chosen?

The Haber process for making ammonia, the conditions used, and why these conditions are a compromise.
A focused answer to the WJEC GCSE Science Double Award Unit 5 topic on industrial chemistry, covering the Haber process for making ammonia, the conditions of temperature, pressure and catalyst, and why these are chosen as a compromise.
9 min answer →