Question

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

Answer 1

When a candle burns, both physical and chemical changes occur:

(i) Physical change: melting of wax, vapourisation of melted wax.

(ii) Chemical change: Burning of vapours of wax to give carbon dioxide, heat and light.

LPG is another example in which physical change occurs when LPG comes out of cylinder and is converted from liquid to gaseous state and a chemical change occurs when gas burns in air.

Answer 2

Dear Student,

◆ Burning of wax -

• Physical change while burning a candle - melting of wax to liquid form.
• Chemical change while burning a candle - combustion of wax to give carbon dioxide.

# Similar example -

Boiling of eggs is another process in which both the chemical and physical changes take place.

• Physical change while boiling egg - solid egg yolk is formed
• Chemical change - proteins are denatured

Thanks dear. Hope this helps you..