Iron pipes coated with zinc do not get rusted easily.

Classify the changes involved in the following processes as physical or chemical changes:

(a) Photosynthesis 
(b) Burning of coal 
(c) Digestion of food 
(d) Dissolving sugar in water 
(e) Melting of wax 
(f) Beating aluminium to make aluminium foil

Which of the following are physical changes and which are chemical changes?

(i) A glass bottle breaking 
(ii) Making a cake 
(iii) Wool being knitted into a sweater 
(iv) Burning of incense stick 
(v) Tearing of paper 
(vi) Cooking of food 
(vii) Formation of clouds 
(viii) Drying of clothes 
(ix) Burning of paper 
(x) Formation of rust