# A student is carrying out a practical investigation to determine the effect of stirring on the rate of reaction between marble chips and hydrochloric acid. Describe the observations and measurements that the student should make to ensure accurate and reliable data.

> OCR A-Level Chemistry A (H432) — 1.1 Practical skills assessed · Describe · 4 marks

## Mark scheme (4 marks)

1. The student describes the initial observations and measurements made before the reaction starts.
2. The student describes the observations and measurements made during the reaction.
3. The student describes the observations and measurements made after the reaction has finished.
4. The student describes the precautions taken to ensure accurate and reliable data.

## Related

- [Revision notes for OCR A-Level Chemistry A (H432)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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-is-carrying-out-a-bb8bdb66) · Published by Druglandscape Ltd.