What is chemicals?
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.
Examples of Artificially Made Chemicals
Human beings probably began combining chemicals before recorded history.
About 5,000 years ago, though, we know that people began combining metals (copper and tin) to create a strong, malleable metal called bronze. The invention of bronze was a major event, as it made it possible to form a huge range of new tools, weapons, and armor.
Bronze is an alloy (a combination of multiple metals and other elements), and alloys have become a staple of construction and trade.
Over the past few hundred years, many different combinations of elements have resulted in the creation of stainless steel, lightweight aluminum, foils, and other very useful products.
Artificial chemical compounds have transformed both the food and pharmaceutical industry. Combinations of elements have made it possible to preserve and flavor food inexpensively, and chemicals are also used to create a range of textures from crunchy to chewy to smooth.
Artificial chemical compounds are a major part of the pharmaceutical industry; by combining active and inactive chemicals in pills, pharmacists can treat many different disorders.