| A | B |
| Law of Conservation of Mass | True for both open and closed systems |
| Double Replacement Reaction | FeS + 2HCl -> FeCl2 + H2S |
| Reactants | substances going into the equation; left side |
| Products | substances coming out of reaction; right side |
| Synthesis Reaction | making more complex compound from simpler substances |
| Precipitate | solid formed from solution in chemical reaction |
| Single Replacement | one element replaces another in a compound |
| Concentration | amount of one material present in a volume of another material |
| Decomposition | products are simpler than the reactants |
| Chemical Formula | shows ratio of elements in a compound |