# Explain how the hydrogen bonding between water molecules gives water a high specific heat capacity, and outline why this property is significant for aquatic organisms.

> IB DP Biology Standard Level (2023 syllabus) — A1.1 Water · Explain · 4 marks

## Mark scheme (4 marks)

1. Water molecules form hydrogen bonds with neighbouring water molecules (due to the partial charges on oxygen and hydrogen atoms / polarity of water).
2. A large amount of energy is required to break the hydrogen bonds, so much heat energy must be absorbed before the temperature of water rises — giving water a high specific heat capacity.
3. The high specific heat capacity means the temperature of water bodies changes slowly / resists rapid temperature fluctuations.
4. This thermal stability is significant for aquatic organisms because enzyme-controlled reactions / metabolic processes require a relatively constant temperature to function efficiently / avoid denaturation.

## Key terms

- [hydrogen bonding](https://www.gradenine.co.uk/glossary/hydrogen-bonding)
- [specific heat capacity](https://www.gradenine.co.uk/glossary/specific-heat-capacity)
- [aquatic organisms](https://www.gradenine.co.uk/glossary/aquatic-organisms)

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](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/explain-how-the-hydrogen-bonding-between-c67a172a) · Published by Druglandscape Ltd.