In chemistry, a substance is a unique form of matter with constant chemical composition and characteristic properties. [1][2] Chemical substances may take the form of a single element or chemical compounds. The meaning of CHEMICAL is of, relating to, used in, or produced by chemistry or the phenomena of chemistry. How to use chemical in a sentence. Chemical changes are different from physical changes, which don't result in a change in substances. One example of a physical change is when water freezes into ice. CHEMICAL definition: 1. any basic substance that is used in or produced by a reaction involving changes to atoms or…. Learn more. A chemical is any substance with a definite composition and distinct properties. All matter is made of chemicals, regardless of whether it is natural or synthetic. Here you can get chemical information (such as chemical physical properties, safety data, Excellent china suppliers and their web addresses and etc.)by searching the name, CAS number, molecular formula, molecular weight, MDL number, EINECS number, structure. CHEMICAL meaning: 1. any basic substance that is used in or produced by a reaction involving changes to atoms or…. Learn more. Search and explore chemical information in the world's largest free chemistry database. Search chemicals by name, molecular formula, structure, and other identifiers. A chemical is any substance that is made of matter, like solids, liquids, or gases. Light, heat, and sound are not chemicals since they are not made of matter. Chemicals can be both natural, like oxygen, or artificial, like stainless steel. Chemical reactions usually involve the making or breaking of chemical bonds. Oxidation, reduction, dissociation, acid–base neutralization and molecular rearrangement are some examples of common chemical reactions.