Question

What are physical changes and chemical changes ?​

Answer 1

Answer:

physical changes are reversible changes

chemical changes are irreversible changes

Answer 2

$\boxed{Physical \:Changes :}$

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.

$\boxed{Examples:-}$

• 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 .

$\boxed{Chemical\: Changes :}$

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

$\boxed{Examples:-}$

• 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 .