| Term | Definition |
| Matter | is anything that has mass and takes up space. |
| Mass | describes the amount of matter in an object. |
| Wieght | is a measure of the gravitational force on an object. |
| Volume | the amount of space that an object takes up, or occupies. |
| Density | is a measure of the amount of mass given volume. |
| physical property | a characteristic of a substance that can be observed and measured without changing the identity of the substance. |
| chemical property | describes a substances ability to change into a new substance with different properties. |
| physical change | is a 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 in ordinary chemical and physical changes, mass is not created or destroyed but is only transformed into different substances. |
| atom | are the smallest unit of an element that maintains the properties of that element. |
| element | is made up of one or more of the same kind of atom chemically combined. |
| compound | is 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 substances | elements and compounds. |
| heterogeneous | mixture is one that does not have a uniform composition. |
| homogenous | mixture. |
| solid | substance has a definite volume and shape. |
| liquid | substance has a definite volume but not shape. |
| gas | does not have a definite volume or shape. |
