The difference between physical and chemical changes is:
1. Physical Changes:
- Physical changes involve alterations in the physical properties of a substance without changing its chemical composition.
- These changes are usually reversible.
- Examples of physical changes include changes in state (solid to liquid, liquid to gas), changes in shape or size, dissolving, melting, freezing, and condensation.
- No new substances are formed during physical changes.
2. Chemical Changes:
- Chemical changes involve the formation of new substances with different chemical compositions.
- These changes are usually irreversible.
- Examples of chemical changes include burning wood (producing ash and smoke), rusting of iron, digestion of food, baking a cake (where ingredients react to form the cake), and fermentation.
- Energy is often absorbed or released during chemical changes.
In summary, physical changes do not involve the formation of new substances and are usually reversible, while chemical changes result in the formation of new substances with different properties and are often irreversible.
