Question

Discuss an example to show that physical and chemical changes can occur together.

Answer 1

An example of simultaneous physical and chemical change:

(1) When a candle is lit, the wax melts and turns into liquid state. As some of the molten wax drops on the floor or table, it solidifies again. Therefore, this is a physical change.

(2) Simultaneously, most of the molten wax rises up the wick,turns into vapour and burns with the flame. Two new substances are formed: water vapour and carbon dioxide. The candle becomes smaller and smaller. This is a chemical change.

Thus, we see that the melting of wax is a physical change and the burning of candle is a chemical change.