Question

what are physical changes and chemical changes ?
what are reversible and irreversible changes ?

Answer 1

Hello friend

Good afternoon

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✔️ physical change : these are those change in which new substance is formed but not with new properties and by physical methods initial substance can be reversed so this is a reversible change.

Example : melting of ice.

✔️ chemical change : these are those changes in which new substance is formed and the properties of chemical properties of new substance is quite different from the initial substance we cannot get the initial substance by physical method for any chemical method this is a Irreversible change.

Example : Rusting of iron

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Reversible changes are those changes in which by physical and chemical method we can get the initial substance where as the Irreversible changes are those changes we cannot get the initial substance from any physical or chemical method.

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I hope it will help you a lot

@drsm

Answer 2

Answer:

Physical changes :-

Those changes in which only physical properties of the substance change but no new substances are formed are called physical changes. Physical Changes temporary and hence can be reversed.

Example:-

● Melting of ice to form water and freezing of water to form ice.

● Boiling of water to form steam and condensation of steam to form water.

● Glowing of a bulb

● Breaking of glass tumbler.( this cannot be reversed but still considered as a physical changes because no new substances are formed )

● Tearing of Paper .

Chemical changes :-

Those changes in which new substances are formed are called chemical changes. Chemical Changes are permanent and hence cannot be reversible.

Example:-

● Burning of magnesium ribbon .

( 2Mg + O2 -> 2MgO)

● Burning of Hydrogen in air .

( 2H2 + O2 -> 2H2O)

● Rusting of Iron

( 2Fe + O2 -> 2FeO)

● Formation iron sulphide from iron and sulphate.

● Burning of Paper .

Explanation: