(a) Define: (i) a physical change (ii) a chemical change (b) Give two examples for each of the above two changes.
(i) Physical change : A temporary change in which no new substance is formed, the composition of substance remains the same, though its state, shape and size may change.
(ii) Chemical change : A permanent change in which new substances are formed whose composition and properties are completely different from those of the original substances.
(b) Physical change:
(i) Change of water into its vapours.
(ii) Heating of iron rod.
(i) Burning of wood.