38. Classify each of the following, as a physical or a chemical change. Give reasons. (i) Drying of a shirt in the Sun. (ii) Rising of hot air over a radiator. (iii) Burning of kerosene in a lantern. (iv) Change in the colour of black tea on adding lemon juice to it. (v) Churning of milk cream to get butter.

(i) Drying of shirt in the Sun is a physical change. As, in this change no new substance is formed. (ii) Since, in rising of hot air over a radiator no new substance is formed, hence it is a physical change. (iii) While burning of kerosene in a lantern, carbon dioxide and water vapour is formed, hence it is a chemical change. (iv) In this change a new substance is formed, hence it is a chemical change. (v) While churning of milk cream to get butter, no new substance is formed, hence it is a physical change.