# Explain why a liquid evaporates at temperatures below its boiling point.

> Cambridge International IGCSE Chemistry (0620) — 1.1 Solids, liquids and gases · Explain · 4 marks

> A puddle of water on a road disappears on a warm day, even though the temperature of the water is well below 100 °C.

## Mark scheme (4 marks)

1. Particles in a liquid have a range of kinetic energies / not all particles have the same energy
2. Some particles at the surface have enough (kinetic) energy to overcome the forces of attraction to neighbouring particles
3. These high-energy particles escape from the surface and become gas / vapour
4. The average kinetic energy of the remaining liquid particles decreases, so the liquid cools / this can happen continuously at any temperature

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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