# Explain how the high latent heat of vaporisation of water, arising from hydrogen bonding, is significant for living organisms.

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

## Mark scheme (4 marks)

1. Hydrogen bonds must be broken for water molecules to escape the liquid surface and vaporise
2. A large quantity of heat energy is absorbed / removed from the surface or organism per gram of water evaporated
3. This allows evaporative cooling to be an effective mechanism for thermoregulation / temperature regulation in organisms
4. The high latent heat of vaporisation also stabilises aquatic / oceanic environments by resisting rapid evaporation, helping to maintain stable habitats for aquatic organisms

## Key terms

- [latent heat of vaporisation](https://www.gradenine.co.uk/glossary/latent-heat-of-vaporisation)
- [hydrogen bonding](https://www.gradenine.co.uk/glossary/hydrogen-bonding)

## Related

- [Revision notes for IB DP Biology Higher 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-high-latent-heat-fc98ad6a) · Published by Druglandscape Ltd.