Question

By giving at least one reason for whether the changes listed below are physical or chemical.

Bursting of crackers.

Answer 1

Chemical change:

• A chemical change is a permanent change in which new substances are formed.
• The chemical change is permanent and cannot be reversed by a simple physical method.
• A chemical change involves an exchange of energy in the form of heat or light.
• For example, rusting of iron, burning of wood, respiration, etc.

The bursting of crackers is a chemical change.

Reason:

• During the bursting of crackers, niter(${\mathrm{KNO}}_3$) carbon, and sulphur burn to form carbon dioxide(${\mathrm{CO}}_2$) as new products.
• This change can not be reversed.
• Hence it is a chemical change.