Question

Changes in which new substances are formed are called _________ changes.

Answer 1

Changes in which new substances are formed are called chemical changes.

Changes are mainly of two types-

1. Physical changes
2. Chemical changes

• Physical changes: A substance is said to undergo a physical change when the chemical properties of a substance do not alter, only changes take place in their physical states.

Example of physical change:

1. Melting of ice
2. Moulding of clay

• Chemical change: A substance is said to undergo a chemical change when the chemical properties of a substance alter. As a result, there is either formation or breaking of atomic bonds at the molecular level.

Examples of chemical change

• Burning of coal
• Digestion of food

Hence, changes in which new substances are formed are called chemical changes.