Question

Classify the following as chemical or physical changes:

• cutting of trees,
• melting of butter in a pan,
• rusting of almirah,
• boiling of water to form steam,
• passing of electric current, through water and the water breaking down into hydrogen and oxygen gases,
• dissolving common salt in water,
• making a fruit salad with raw fruits, and
• burning of paper and wood.

NCERT Class 9th Science Ch 2 Is Matter Around Us Pure

Answer 1

Physical changes:

Those changes in which no new substances are formed are called physical changes. In a physical change the substances involved do not change their identity.
The physical changes are temporary changes which can be reversed easily to form the original substance.


Chemical changes:

Those changes in which new substances are formed are called chemical changes. In a chemical change the substances involved change their identity. The chemical changes are permanent changes which are usually Irreversible.


Solution:

CHEMICAL CHANGES:

• cutting of trees
,• rusting of almirah
• passing of electric current, through water and the water breaking down into hydrogen and oxygen gases
• burning of paper and wood.


PHYSICAL CHANGES:

• melting of butter in a pan
• boiling of water to form steam
• dissolving common salt in water
• making a fruit salad with raw fruits

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Hope this will help you....

Answer 2

Answer:

This picture helps you

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