Give two examples for each of the following cases:

(a) Physical changes which are reversible.

(b) Physical changes which are not reversible.

(c) Chemical changes.

(a) Examples of physical changes which are reversible:

i) Melting of wax.

ii) Formation of sugar crystals from its solution.

(b) Examples of physical changes which are not reversible:

i) Tearing of paper

ii) Cutting log of wood

(c) Examples of chemical changes:

i) Reaction between lime water and carbon dioxide

ii) Burning of magnesium ribbon