Question

class 7th notes of science ch 6​

Answer 1

Answer:

Here are your notes ..

1. Changes can be of two types - Physical and Chemical.

2.Physical changes - are changes in which no new substances are formed. These changes are reversible.

3. Chemical changes - are changes in which new substances are formed. These changes are irreversible.

4. A film of brownish substance is called rust and the process is called rusting.

5. For rusting, the presence of both oxygen and water (or water vapour) is essential.

6. Galvanisation - The process of depositing a layer of zinc is called galvanisation.

7. Crystallisation - It is the method of preparing crystals of copper sulphate.

This much..

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