Name a physical change that is irreversible and a chemical change which is reversible.

Irreversible Physical change: Cutting of trees, tearing of paper
Reversible chemical change: Some reactions can be reversed. They have a backward and forward arrow. 
Eg: ​ NITROGEN DIOXIDE

When the gas nitrogen dioxide is heated, a forward chemical reaction changes the brown nitrogen dioxide gas into two colourless gases – nitrogen monoxide and oxygen. However, if these colourless gases are cooled, they will re-form into brown nitrogen dioxide gas. This is called a backward chemical reaction.