Riot control agent. After September 11, 2001, the _____________ was established to provide a framework that provides a comprehensive national approach, applicable at all jurisdictional levels and across functional disciplines.
noun, plural: chemicals. (1) A substance made up of chemical elements or produced from a chemical process. (2) A drug, especially illicit or addictive drug. adjective. Of, relating to, or pertaining to, chemistry or a chemical substance.
Science for Youth May 16, 2011. A chemical compound is a substance composed of two or more different elements chemically bonded together in a fixed proportion by mass. When a compound is formed from its components, a chemical change takes place through chemical reactions.