Melting, freezing and boiling points
Matter exists in three states: solid, liquid and gas. Heating turns ice into water and water into steam; supplying or removing heat changes a substance from one state to another.
Figure to be added
Change of state
Matter passing from one state to another is a change of state: a gas condensing, a solid melting, a liquid freezing, a liquid boiling.
Melting point
The temperature at which a solid being heated turns to liquid.
Freezing point
The temperature at which a liquid being cooled turns to solid — the same as the melting point.
Boiling point
The temperature at which a liquid bubbles as it turns to vapour throughout.
Melting points — table 9.2
| Substance | Melting point (°C) |
|---|---|
| Ice | 0 |
| Paraffin wax | 54 |
| Naphthalene | 80 |
| Sulphur | 114 |
| Lead | 330 |
| Zinc | 410 |
| Aluminium | 660 |
| Gold | 1063 |
| Iron | 1535 |
| Tungsten | 5385 |
Boiling points — table 9.3
| Substance | Boiling point (°C) |
|---|---|
| Oxygen | −183 |
| Ethanol | 78 |
| Water | 100 |
| Mercury | 357 |
| Zinc | 907 |
| Copper | 2310 |
| Iron | 2750 |
These depend on pressure, and are given at a pressure of one atmosphere.