Question

Classify the changes involved in the following processes as physical or chemical changes: (a) Photosynthesis (b) Dissolving sugar in water (c) Burning of coal (d) Melting of wax (e) Beating aluminium to make aluminium foil (f) Digestion of food

Answer 1

Physical change:

A change in matter that does not affect its chemical properties. If we shape a piece of wood into a baseball bat, it will still burn in a fire and float in water.
Melting, freezing, condensing, breaking, crushing, cutting, and bending are all instances of physical transformations.

Classification of physical change:

1. (d) Melting of wax.
2. (e) Beating aluminum to make aluminum foil.

Chemical change:

1. When the chemical properties of a substance change, it is said to have undergone a chemical change.
2. As a result, atomic bonds are either formed or broken at the molecular level.

Classification of chemical change:

1. (a) Photosynthesis.
2. (b) Dissolving sugar in water.
3. (c) Burning of coal.
4. (f) Digestion of food.