| Atomic weight | the average atomic mass for a naturally occurring element, expressed in atomic mass units. |
| Limiting reactant | the reactant that is entirely consumed when a reaction goes to completion. |
| Mole (mol) | the quantity of a given substance that contains as many molecules or formula units as the number of atoms in exactly 12 g of carbon- 12. The amount of substance containing Avogadro's number of molecules or formula units |
| Product | a substance that results from a chemical reaction |
| Reactant | a starting substance in a chemical reaction |
| Stoichiometry | the calculation of the quantities of reactants and products involved in a chemical reaction |