Briefly answer the following:
 
Distinguish between reversible and irreversible changes.
 
Reversible changes Irreversible changes
Reversible changes are changes that . Irreversible changes are changes that .
In these changes,  and the process can be undone. In these changes, , and the change is permanent.
They are usually . They are usually .
Examples include melting of ice and freezing of water. Examples include burning of paper and cooking of food.