Is the change observed a physical change or a chemical change (reaction)
To make that determination, we need to consider the nature of the change and how it affects the substances involved.
Physical changes involve a change in the appearance, texture, or state of matter of a substance without changing its chemical composition. Examples of physical changes include melting, freezing, dissolving, and changes in shape or size.
Chemical changes, on the other hand, result in the formation of new substances with different chemical compositions. Examples of chemical changes include burning, rusting, cooking, and digestion.
If the change observed involves a rearrangement of atoms and the formation of new substances, then it is a chemical change. If the change involves only a change in state, shape, or form without altering the chemical composition of the substances, then it is a physical change.