Physical changes only change the appearance of a substance, not its chemical composition.
Chemical changes cause a substance to change into an entirely substance with a new chemical formula.
Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the end results are called products.
Terms
chemical changeA process that causes a substance to change into a new substance with a new chemical formula.
chemical reactionA process involving the breaking or making of interatomic bonds and the transformation of a substance (or substances) into another.
physical changeA process that does not cause a substance to become a fundamentally different substance.
There are two types of change in matter: physical change and chemical change. As the names suggest, a physical change affects a substance’s physical properties, and a chemical change affects its chemical properties. Many physical changes are reversible (such as heating and cooling), whereas chemical changes are often irreversible or only reversible with an additional chemical change.
Physical & Chemical Changes – YouTubeThis video describes physical and chemical changes in matter.
Physical Changes
Another way to think about this is that a physical change does not cause a substance to become a fundamentally different substance but a chemical change causes a substance to change into something chemically new. Blending a smoothie, for example, involves two physical changes: the change in shape of each fruit and the mixing together of many different pieces of fruit. Because none of the chemicals in the smoothie components are changed during blending (the water and vitamins from the fruit are unchanged, for example), we know that no chemical changes are involved
