| Term | Definition |
| Chemistry | is the study of the properties of matter how matter changes. |
| Element | Is a substance that cannot be broken into any other substances b chemical or physical means. |
| Compound | Is a substance made of two or more elements chemically combined in a specific ration, or proportion. |
| Mixture | Is made from two or more pure substances-elements, compounds, or both- that are in the same place but not combined as a new material. |
| Solution | is a well-mixed mixture. |
| Precipitate | A solid that forms from solution during a chemical reaction is called a |
| atom | The smallest particle of an element is an |
| Molecule | the combination of two or more atoms. |
| Chemical bonds | The force that holds atoms together is called |
| Chemical equation | is a shorter, easier way to show that chemical reactions, using symbols instead of words. |
| Symbol | Most elements are represented by a one-letter or two-letter |
| Chemical formula | A compound is represented by a "word", which shows the ratio of elements in the compound is called |
| subscript | shows the number of atoms of an element in a molecule. |
| reactants | The materials you have at the beginning of a chemical reaction are |
| products | When the reaction is complete, you have different materials, called the ____ of the reaction. |
| Conservation of matter | The principle stating that matter is not created or destroyed during a chemical reaction is |
| Coefficient | is a number in front of a chemical formula in the equation. |
| Synthesis | When two or more substances (elements or compounds) combine to make a more complex substance, the process is called |
| Decomposition | reaction breaks down compounds into simpler products. |
| replacement reaction | a reaction in which one element replaces another in a compound or in which two elements in different compounds trade places, is called a |
| Exothermic reaction | A reaction that releases energy in the form of heat is called |
| endothermic reaction | A reaction that absorbs energy is called an |
| Activation Energy | is the minimum amount of energy that has to be added to start a reaction. |
| Concentration | is the amount of one material in a given volume of another material. |
| catalyst | A material that increases the rate of a reaction by lowering the activation energy. |
| Enzymes | provide a surface on which reactions take places. |
| inhibitor | A material used to decrease the rate of a reaction is called an |
| Combustion | a Rapid reaction between oxygen and a substance called a fuel |
| Fuel | is a material that releases energy when it burns |
