Why is the melting of butter to make ghee considered a chemical change?

Melting butter to make ghee is not considered a chemical change, but a physical change.

Physical change is a change in the form or appearance of a substance without changing its chemical composition. In the case of melting butter to make ghee, the butter is heated until the water content evaporates, leaving behind the clarified butterfat, or ghee. The chemical composition of the butter remains the same throughout this process.

On the other hand, a chemical change occurs when the chemical composition of a substance changes, resulting in the formation of one or more new substances. For example, when iron rusts, it undergoes a chemical change as it reacts with oxygen to form iron oxide.