1. Pure Substances:
* Elements: These are the simplest form of matter, like gold (Au), oxygen (O), and carbon (C).
* Compounds: Formed when two or more elements chemically combine in a fixed ratio, like water (H₂O), salt (NaCl), and carbon dioxide (CO₂).
2. Mixtures:
* Homogeneous Mixtures: Components are evenly distributed throughout, like saltwater or air.
* Heterogeneous Mixtures: Components are not evenly distributed, like sand and water or a salad.
3. Everything Else!
* Living Organisms: Made up of complex combinations of elements, especially carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
* Materials: Many materials we use daily, like plastics, metals, ceramics, and fabrics, are made from combinations of elements.
* The Earth and Universe: The Earth's crust, mantle, and core, as well as stars and planets, are composed of elements.
Essentially, everything around us is ultimately formed from elements in various combinations.
