Solution 2 ( Physical and Chemical Changes)

A change in which one or more new substances are formed is called chemical change. It is also known as chemical reaction.

Eg:- Medicines, plastic, detergent etc are produced by chemical change.

In addition to new products other changes can occurs in a chemical change which are given below:

(i)Heat, light or any other radiation may be given off or absorbed.

Eg:-Burning of any substance

(ii) Sound may be produced.

Eg:- Explosion of fireworks that produces light, heat, sound and gases.

(iii)A change in smell may take place or a new smell may be given off.

Eg:-Rotten food items produce smell.

(iv) A colour change may take place.

Eg:- colour of apple, potato and brinjal slice changed to brown if it is not consumed immediately.

(v) A gas may be formed.

Eg:- Explosion of fireworks, candle flame produces gas.

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NCERT solutions class 7


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