| Term | Definition |
| Matter | Anything that has mass and takes up space |
| Volume | The amount of space that an object takes up, or occupies |
| Mass | Describes the amount of matter in an object |
| Density | Measure of the amount of mass in a given volume |
| Weight | A measure of the gravitational force |
| Physical Property | Characteristic of a substance that can be observed and measured without changing the identity of the substance |
| Chemical Property | Describes a substance's ability to change into a new substance with different properties |
| Physical Change | Change that affects one or more physical properties of a substance |
| Chemical Change | Occurs when one or more substances change into entirely new substances with different properties. |
| Law of Conservation of Mass | States that ordinary chemical and physical changes mass is not created or destroyed but is only transformed into a different substance |
| Atom | The smallest unit of element that maintains the properties of that element |
| Element | Made up of one or more of the same kind of atom chemically combined |
| Compound | Made up of different kinds of atoms chemically combined |
| Mixture | Contains a variety of elements and compounds that are not chemically combined with each other |
| Pure Substance | Elements and compounds |
| Heterogeneous | Mixture is one that does not have a uniform composition |
| Homogeneous | When you add sugar to a cup of water it dissolves |
| Solid | Substance has a definite volume and shape |
| Liquid | Substance has a definite volume but not a definite shape |
| Gas | Particles are close together and can slide past each other |
| Freezing | Change in state when a liquid becomes a solid |
| Melting | Change in state from a solid to a liquid |
| Evaporation | When particles gain enough energy that they become a gas |
| Boiling | A rapid change from a liquid to a gas |
| Condensation | Change in state from a gas to a liquid |
| Deposition | Change from gas to a solid |
| Sublimation | Change from a solid to a gas |
