Chemical change – A substance is said to undergo a physical change when only the physical properties such as the shape, size, colour, state or appearance of the substance change. Its chemical composition remains intact.
Physical change – A substance is said to undergo a chemical change when the chemical properties of a substance alter. As a result, there is either formation or breaking of atomic bonds at the molecular level.
(a) Cutting of trees – Physical change
(b) Melting of butter in a pan – Physical change
(c) Rusting of almirah – Chemical change
(d) Boiling of water to form steam – Physical change
(e) Passing of electric current through water and the water breaking down into hydrogen and oxygen gases – Chemical change
(f) Dissolving common salt in water – Physical change
(g) Making a fruit salad with raw fruits – Physical change
(h) Burning of paper and wood – Chemical change