When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of familiar process in which both the chemical and physical changes take place.

Question

Philoid · Accepted Answer

1) When a candle burns, both physical and chemical changes take place.

Physical change: Melting of wax is a physical change since it again turns into solid wax on cooling.

Chemical change: The wax near to flame burns and gives new substances like carbon dioxide.

2) Lighting torch bulb using the dry cell is another example where both physical and chemical changes takes place.

Physical change: The lighting of a bulb is a physical change since no new substance is formed.

Chemical change: The current is obtained from the chemical substances present inside the dry cell. Inside the cell, the chemicals react with each other and produce light substances and hence the cell ultimately becomes useless. So, it is a chemical change.