Final answer:
A chemical change involves a change in the composition of substances, resulting in the formation of new substances with different properties. A physical change, on the other hand, only alters the appearance or display of matter without changing its composition.
Step-by-step explanation:
A chemical change and a physical change differ in terms of composition. In a chemical change, there is a change in the composition of the substances involved. This means that new substances are formed with different properties. On the other hand, a physical change only alters the appearance, smell, or display of a sample of matter without changing its composition. The mass, number of atoms, and number of molecules stay the same during a physical change.