Pertaining to chemistry: as, a chemical experiment.Pertaining to the phenomena with which chemistry deals and to the laws by which they are regulated; accordant with the laws of chemistry.Also chemic.CaCl2 + Na2CO3 = CaCO3 + 2NaCl.This is a true equation in the algebraic sense, because the value of the two members is the same. Since matter is indestructible, nothing is lost in the reaction, and the weights of calcium chlorid and sodium carbonate which reacted must be precisely the same as the combined weights of the resultant calcium carbonate and sodium chlorid.n. A substance produced by a chemical process; a chemical agent prepared for scientific or economic use: as, the manufacture of chemicals.Versed in chemistry; engaged in the study of chemistry or in chemical research or investigation: as, a chemical philosopher; a chemical friend.Of or pertaining to alchemy or alchemists. Also chymical.