This document discusses key concepts in chemistry including:
- Chemistry is the study of matter which is anything that has mass and takes up space. All matter is made of atoms.
- Pure substances can be elements, which contain only one type of atom, or compounds, which contain two or more elements in a fixed ratio. Mixtures contain two or more substances mixed together.
- Properties describe characteristics of matter and can be physical, relating to a substance's observable properties, or chemical, relating to how it interacts with other substances.
- A chemical change forms new substances while a physical change only alters a substance's physical properties like state.
- Chemical tests can identify substances by their reactions and common tests are described