# A student makes a solution of citric acid for a food science experiment. The student uses 0.050 mol of citric acid and dissolves it in 250 cm³ of water. Explain what happens to the concentration of the citric acid solution if the student had instead dissolved the same amount of citric acid in 500 cm³ of water.

> AQA GCSE Chemistry (8462) — 4.3.4 Using concentrations of solutions in mol/dm³ (Chem only) · Explain · 4 marks

## Mark scheme (4 marks)

1. The concentration would decrease / be lower / be halved
2. Because the same amount (number of moles) of solute is dissolved in a larger volume of solution
3. Original concentration = 0.050 ÷ 0.250 = 0.20 mol/dm³
4. New concentration = 0.050 ÷ 0.500 = 0.10 mol/dm³

## Key terms

- [concentration](https://www.gradenine.co.uk/glossary/concentration)
- [solution](https://www.gradenine.co.uk/glossary/solution)

## Related

- [Revision notes for AQA GCSE Chemistry (8462)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-makes-a-solution-of-62b65f8d) · Published by Druglandscape Ltd.