Balancing Equations PhET A chemical equation is shorthand way of expressing what is happening in a chemical reaction. The Law of Conservation of Matter states that matter cannot be created nor destroyed. This holds true for chemical equations. It means that the number of atoms of an element must be equal on both sides of an equation. In other words, the equation must be balanced. This idea became a scientific law because many careful experiments indicated that mass is the same before and after a chemical or physical change. Examine the chemical equation below: Reactant Side N2 + H2 Product Side NH3 1. If you weighed the atoms that appear on the reactant side of the equation, would they have the same mass as the atoms that appear on the product side? Tell how you know.

2. How many atoms of nitrogen appear to be on the reactant side? The product side?

3. How many atoms of hydrogen appear to be on the reactant side. The product side?

4. Do you feel that this equation is currently following the law of conservation of mass?