Question

20. How do the following changes differ from one another?
(a) Melting of wax
(b) Burning of wax​

Answer 1

Answer:

(a) Melting of wax is a physical change.

(b) Burning of wax is a chemical change.

Explanation:

(a)No new substances are formed. In a burning candle, there are both physical and chemical changes. The melting of the solid wax to form liquid wax and the evaporation of liquid wax to form wax vapour are physical changes. The burning of the wax vapour is a chemical change.

(b)Burning of candle melts the wax and hence physical state of wax has changed from solid to liquid. Again the wax combines with the atmosphere oxygen and changes to carbon dioxide, heat and light.

Answer 2

• answer:-
• (a) melting of wax :- physical change
• (b) burning of wax :- chemical change .