Explanation:
A physical change is defined as the change in which there occurs no difference in chemical composition of a substance.
For example, change in shape, size, mass, density, volume etc are all physical changes.
When we cut iron into pieces then it is a physical change because we are changing its size and not its chemical composition.
On the other hand, a chemical change is defined as the change in which there occurs difference in chemical composition of the substance.
For example, toxicity, reactivity, combustion etc are all chemical changes.
When iron rusts then an oxide layer of orange-brown color deposits on its surface due to chemical combination of air and moisture with iron. This is a chemical change.
