Question

Classify the following processes into physical or chemical changes and explain the reason in one sentence. (4 marks)

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

Answer 1

• Beating of aluminium metal to make aluminium foil does not involve change in their composition. Only the shape changes. So, it is a physical change. (1 mark)​​​​​​
• Digestion of food is a chemical change as the food breaks down and forms new substance inside the stomach. (1 marks)
• During cutting of a log of wood into pieces, change in size and shape occurs. While the material remains same. So, it is categorised as physical change. (1 mark)
• Rusting of iron is a chemical change as a reddish-brown flaky layer (rust) is formed on its surface when it is left in air. (1 mark)