| A | B |
|---|
| element | a substance that cannot be separated or broken down into smaller substances by chemical means |
| molecule | the smallest unit of a substance that behaves like the substance; such as water (H20) or oxygen (O2) |
| matter | anything that has mass and takes up space |
| atom | the smallest unit of an element that maintains the chemical properties of that element |
| compound | a substance made up of atoms of two or more different elements joined by chemical bonds |
| pure substance | a sample of matter, either a single element or a single compound, that has definite chemical and phsyical properties |
| mixture | a combination of two or more substances that are not chemically combined |
| melting point | the temperature and pressure at which a solid becomes a liquid |
| boiling point | the temperature and pressure at which a liquid becomes a gas |
| density | the ratio of the mass of a substance to the volume of the substance |
| reactivity | the capacity of a substance to combine chemically with another substance |
| physical change | the change of matter from form to another without a change in chemical properties |
| chemical change | a change that occurs when one or more substances change into entirely new substances with different properties |
