Physical and Chemical Changes

Topic Content:

Physical Change:

A physical change is a change in which no new substance is formed . The substance may change in state, shape, size or appearance, but its chemical identity remains the same. Many physical changes can be reversed.

For example:

• When ice (solid) is heated, it melts to form water (liquid).
• When the water is cooled, it solidifies back into ice .

\( \scriptsize \underset{solid}{ice} \rightarrow \underset{liquid}{water}\rightarrow \underset{solid}{ice} \)

Other Examples of Physical Changes:

1. Dissolving common salt in water.
2. Melting of ice, candle wax, or butter.
3. Freezing of liquids to solids.
4. Vaporisation of liquids (e.g. water to steam).
5. Liquefaction of gases (turning gas into liquid).
6. Sublimation of substances like camphor or iodine.
7. Magnetisation of iron.

Chemical Change: