# A student reacts zinc with excess hydrochloric acid to produce zinc chloride. The theoretical yield of zinc chloride is 40 g. The student collects 30 g of zinc chloride. Explain why the actual yield is less than the theoretical yield, and calculate the percentage yield.

> AQA GCSE Chemistry (8462) — 4.3.3 Yield and atom economy of chemical reactions · Explain · 4 marks

> Zinc reacts with hydrochloric acid according to the following equation: Zn + 2HCl → ZnCl₂ + H₂. The theoretical yield of zinc chloride is 40 g and the student collects an actual yield of 30 g.

## Mark scheme (4 marks)

1. Identifies a valid reason why actual yield is less than theoretical yield
2. Identifies a second valid reason why actual yield is less than theoretical yield
3. Correct method: percentage yield = (actual yield ÷ theoretical yield) × 100
4. Correct final answer: 75%

## Key terms

- [actual yield](https://www.gradenine.co.uk/glossary/actual-yield)
- [theoretical yield](https://www.gradenine.co.uk/glossary/theoretical-yield)
- [percentage yield](https://www.gradenine.co.uk/glossary/percentage-yield)

## 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)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-reacts-zinc-with-excess-38734373) · Published by Druglandscape Ltd.