# 4-mark practice questions — WJEC GCSE Chemistry (Wales)

> 60 questions · chemistry

## How to answer

4-mark questions are the shortest levels-of-response band. Aim for four scientific ideas, each in its own short sentence.

## Sample questions

1. [A food scientist is checking the purity of a sample of vanilla flavouring before it is used in a product. She carries ou…](https://www.gradenine.co.uk/q/a-food-scientist-is-checking-the-01163e29)
2. [When water boils, it undergoes a physical change rather than a chemical change. Explain the difference between a physica…](https://www.gradenine.co.uk/q/when-water-boils-it-undergoes-a-030e473d)
3. [Describe what happens when a metal oxide reacts with a dilute acid, and explain why the product formed is called a salt.…](https://www.gradenine.co.uk/q/describe-what-happens-when-a-metal-06fe3779)
4. [Calcium hydroxide solution is used to test for carbon dioxide gas. Explain what is observed when carbon dioxide is bubbl…](https://www.gradenine.co.uk/q/calcium-hydroxide-solution-is-used-to-081866a0)
5. [Propane (C₃H₈) is a hydrocarbon fuel used in camping gas stoves. When propane burns completely in oxygen, carbon dioxide…](https://www.gradenine.co.uk/q/propane-c-h-is-a-hydrocarbon-fuel-1015689b)
6. [A chemist is investigating whether a sample of red food colouring is a pure substance or a mixture. She carries out pape…](https://www.gradenine.co.uk/q/a-chemist-is-investigating-whether-a-18de981c)
7. [Crystallisation can be used to obtain a pure salt from a solution. Describe the steps involved in obtaining pure copper …](https://www.gradenine.co.uk/q/crystallisation-can-be-used-to-obtain-18e1258c)
8. [A student wants to obtain a sample of pure water from a salt solution. Describe how simple distillation could be used to…](https://www.gradenine.co.uk/q/a-student-wants-to-obtain-a-1c4ca3e2)

## Related

- [WJEC GCSE Chemistry (Wales) revision notes](https://www.gradenine.co.uk/learn/wjec-gcse-chemistry-wales)
- [WJEC GCSE Chemistry (Wales) past papers](https://www.gradenine.co.uk/past-papers/wjec-gcse-chemistry-wales)
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