59 – Chemical reactions
Publisher Summary 
This chapter provides an overview on chemical reactions. Chemical reaction occurs when one or more substances undergo a rearrangement of their constituent atoms to form new substance. This rearrangement of atoms taking part in a chemical reaction is represented by chemical shorthand in which the elements and compounds undergoing reaction are assigned by their chemical symbols of formulae. The reactions are usually written in the form of an equation in which the number of atoms of each element on each side of the equality sign is the same. A recent addition to these chemical equations has been the introduction of suffices to show the phase of the substances, (s) to represent a solid, (l) a liquid, (aq) an aqueous solution and (g) a gas. Most chemical reactions can be broadly classified in three categories, namely, acid-base reactions, double decomposition reactions, and redox reactions.