Question

What is physical and chemical change???

Answer 1

There are several differences between physical and chemical change in matter or substances.

A physical change in a substance does not change what the substance is.

In chemical change where there is a chemical reaction,a new substance is formed and energy is either given off or absorbed.

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: