A chemical is any substance consisting of matter. This includes any liquid, solid, or gas. A chemical is any pure substance (an element) or any mixture (a solution, compound, or gas). Chemicals occur naturally and can be made artificially.
EXAMPLES OF NATURALLY-OCCURRING CHEMICALS
Naturally-occurring chemicals can be solid, liquid, or gas. Naturally occurring solids, liquids, or gases may be made up of individual elements or may contain many elements in the form of molecules.
Gases. Oxygen and nitrogen are naturally occurring gases. Together, they make up most of the air we breathe. Hydrogen is the most common naturally-occurring gas in the universe.
Liquids. Perhaps the most important naturally occurring liquid in the universe is water. Made up of hydrogen and oxygen, water behaves differently from most other liquids: it expands when frozen. This natural chemical behavior has had a profound effect on the geology, geography, and biology of Earth and (almost certainly) other planets.
Solids. Any solid object found in the natural world is made up of chemicals. Plant fibers, animal bones, rocks, and soil are all made up of chemicals. Some minerals, such as copper or zinc, are made entirely from one element. But granite, for example, is a metamorphic rock made up of multiple elements.
