Answer:
Physical changes are those in which the shape, size, or state of the matter changes, but the substance is still essentially the same. Chemical changes are those where one or more substances are combined to produce a new substance.
Step-by-step explanation:
For example, chopping up a carrot or ice melting into water are both physical changes. Chemical changes are those where one or more substances are combined to produce a new substance. At the end of a chemical change, you have a new substance. Burning a piece of paper would be a chemical change, as would baking a cake. Ozone is an invisible gas made of 3 oxygen atoms.