Chemical reactions are taking place all around you and even inside of you.  For example, when you eat a piece of food, you begin to digest it.  Chemicals in your mouth mix with food, and then chemicals break down that food for your body to use as energy.  A chemical reaction is a change in which one or more substances are converted into new substances.  The substances that react are called reactants, and the new substances produced are called products.  The law of conservation of mass states that the total starting mass of all reactants equals the total final mass of all products.  Atoms are not created or destroyed; they simply get shuffled around.  A chemical equation uses chemical formulas and symbols to describe a chemical reaction and the product it produces.

Review:

1. What is a chemical reaction?
2. The new substances that are created during a chemical reaction are called _________.
3. Explain the law of conservation of mass.