Views:23 Author:Site Editor Publish Time: 2020-04-24 Origin:Site
What Is a Chemical and What Isn't a Chemical?
Chemicals make up all matter—but they don't make up everything.
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). They can either occur naturally or can be created artificially.
What Is Not a Chemical?
If anything made of matter is made up of chemicals, which means that only phenomena that aren't made of matter are not chemicals: Energy is not a chemical. Light, heat, and sound are not chemicals—nor are thoughts, dreams, gravity, or magnetism.
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 because 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 and zinc, are made entirely from one element. Granite, on the other hand, is an example of an igneous rock that's made up of multiple elements.
Examples of Artificially Made Chemicals
Human beings probably began combining chemicals before recorded history. About 5,000 years ago, 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 the food industry. Combinations of elements have made it possible to preserve and flavor food inexpensively. Chemicals are also employed to create a range of textures from crunchy to chewy to smooth.
Artificial chemical compounds have also had a profound impact on the pharmaceutical industry. By combining active and inactive chemicals in pills, researchers and pharmacists are able to create the medicines required to treat a wide variety of disorders.
Chemicals in Our Daily Lives
We tend to think of chemicals as being undesirable and unnatural additions to our food and air. In fact, chemicals make up all of our foods as well as the air we breathe. However, some chemical compounds added to natural foods or gases can cause significant problems.
For example, a chemical compound called MSG (monosodium glutamate) is often added to food to improve its flavor. MSG, however, can trigger headaches and other adverse negative reactions. And while chemical preservatives make it possible to keep food on the shelves without spoiling, some preservatives, such as nitrates, have been found to have carcinogenic (cancer-causing) properties, especially when overused.