Question

How can we identify whether the change occured is a chemical or physical change?

Answer 1

Physical Change	Chemical Change
The chemical composition of a substance undergoing a physical change remains same.	The chemical composition of a substance undergoing a chemical change does not remain same.
Most of the physical changes are reversible.	Most of the chemical changes are irreversible.
No new substances are formed during a physical change.	Formation of new substances takes place during a chemical change.
Little or no heat change is observed.	Considerable heat changes are involved.

These are the some differences which can be used to distinguish physical and chemical changes.