Changes of State (OCR GCSE Physics A (Gateway Science Suite)): Revision Notes
📚 Revision Notes
3.1.4 Changes of State
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Mass is conserved during a change of state. If 20g of liquid evaporates, the gas produced will also weigh 20g
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These physical changes are reversible, and not chemical changes They are not chemical because the material retains its original properties when reversed
Graph of Changes of State
- Temperature vs. Time:
- Solid: Heating up to the melting point
- Melting: Transition from solid to liquid
- Liquid: Heating up to boiling point
- Boiling: Transition from liquid to gas
- Gas: Heating up further
Evaporation
infoNote
The liquid turns into a gas, but only on the surface of the liquid. Only the particles on the surface have enough energy to turn into a gas.
Table of Changes of State Processes
| Process | From State | To State | Description |
|---|---|---|---|
| Melting | Solid | Liquid | Solid to Liquid |
| Freezing | Liquid | Solid | Liquid to Solid |
| Boiling | Liquid | Gas | Liquid to Gas |
| Condensation | Gas | Liquid | Gas to Liquid |
| Sublimation | Solid | Gas | Solid to Gas |
| Deposition | Gas | Solid | Gas to Solid |