# "Describe and explain" questions — WJEC A-Level Chemistry (Wales)

> 16 questions · chemistry

## How to answer

"describe and explain" questions from WJEC A-Level Chemistry (Wales). Read the rubric carefully — the marking points cluster into scientific ideas rather than free-form prose.

## Sample questions

1. [Bromoethane can undergo a substitution reaction with potassium cyanide solution to form a new organic compound. Describe…](https://www.gradenine.co.uk/q/bromoethane-can-undergo-a-substitution-reaction-013aaa30)
2. [Alkanes and alkenes are two families of hydrocarbons. Describe how bromine water can be used to distinguish between an a…](https://www.gradenine.co.uk/q/alkanes-and-alkenes-are-two-families-05dc3107)
3. [A student has a sample of propanal and a sample of propanone. She wants to confirm which sample is which using a chemica…](https://www.gradenine.co.uk/q/a-student-has-a-sample-of-17676ec0)
4. [Ethanol is an alcohol that can be produced by the fermentation of glucose. Describe the fermentation process and explain…](https://www.gradenine.co.uk/q/ethanol-is-an-alcohol-that-can-48c6f507)
5. [Ethanoic acid is a carboxylic acid. Describe what happens when ethanoic acid reacts with sodium carbonate solution, and …](https://www.gradenine.co.uk/q/ethanoic-acid-is-a-carboxylic-acid-5901dde9)
6. [Mendeleev developed an early version of the periodic table. Describe how Mendeleev arranged the elements in his periodic…](https://www.gradenine.co.uk/q/mendeleev-developed-an-early-version-of-61fc0621)
7. [Chlorine, bromine and iodine are all elements in Group 7 of the periodic table. Describe how the reactivity of the Group…](https://www.gradenine.co.uk/q/chlorine-bromine-and-iodine-are-all-6a33d21b)
8. [Ethanol is an alcohol that can be produced by fermentation. Describe what is meant by fermentation and explain why ethan…](https://www.gradenine.co.uk/q/ethanol-is-an-alcohol-that-can-802d6d2d)

## Related

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