Question

Classify the following processes into physical or chemical changes:​

(i) Beating of aluminium metal to make aluminium foil.​
(ii) Digestion of food.
(iii) Cutting of a log of wood into pieces.
(iv) Burning of crackers.

Answer 1

(i) Physical change: Beating of aluminium metal makes the metal thinner like an aluminium foil as the aluminium composition does not change so it is a physical change.​

(ii) Chemical change: During digestion the food breaks down into simpler forms to be used by the body as the chemical composition of the food changes. Hence it is a chemical change.​

(iii) Physical change: Cutting of a log of wood into pieces does not change the chemical composition of wood so it’s a physical process which is irreversible.​

(iv) Chemical change: Burning of crackers involves release of heat and production of sound and its also an irreversible process so it’s a chemical change.​