"Explain" questions — WJEC GCSE Chemistry (Wales)
49 questions · chemistry · View as Markdown
How to answer
WHAT + WHY. Every point paired with a because. Structure: X happens because Y. This causes Z because … Assessment Objective: AO2. Every "explain" answer on this spec is marked against exactly this pattern.
Sample questions
- A food scientist is checking the purity of a sample of vanilla flavouring before it is used in a product. She carries ou…
- When water boils, it undergoes a physical change rather than a chemical change. Explain the difference between a physica…
- Calcium hydroxide solution is used to test for carbon dioxide gas. Explain what is observed when carbon dioxide is bubbl…
- Propane (C₃H₈) is a hydrocarbon fuel used in camping gas stoves. When propane burns completely in oxygen, carbon dioxide…
- A chemist is investigating whether a sample of red food colouring is a pure substance or a mixture. She carries out pape…
- A student makes a salt by reacting dilute nitric acid with sodium hydroxide solution. Explain why this reaction produces…
- Chlorine has two main isotopes: chlorine-35 and chlorine-37. Explain what is meant by the term isotope and describe how …
- Methanol (CH₃OH) and ethanol (C₂H₅OH) are both members of the alcohol homologous series. Explain why ethanol has a highe…