States of matter – a short recap
Learn with an AI tutor
An AI tutor explains this page to you and helps you with the exercises. Choose your assistant:
Open with Claude Open with ChatGPT Open with Mistral Vibe
You use your own account with the provider. The assistant is not offered by lernapps.net: lernapps only provides the content and the exercises. The choice holds for all pages, on this device only.
Rule
Three properties help to sort substances:
- The state of matter at room temperature (20 °C): solid, liquid or gaseous.
- The melting point: from this temperature a solid becomes liquid.
- The boiling point: from this temperature a liquid becomes gaseous.
- Melting point
The temperature at which a solid becomes liquid. For a pure substance it is always the same.
- Boiling point
The temperature at which a liquid becomes gaseous. For a pure substance it is always the same.
Memory aid
If room temperature (20 °C) is below the melting point, the substance is solid. If it lies between the melting and the boiling point, it is liquid. If it is above, it is gaseous.
Example
Why is water liquid at 20 °C?
Water melts at 0 °C and boils at 100 °C. Room temperature (20 °C) lies in between. That is why water is liquid at 20 °C.