ABSTRACT
Chemical process industries convert natural raw materials into products that are of higher economic value than the starting material. This is carried out in a sequence of steps involving physical and chemical transformations, the former being known as unit operations and the latter as unit processes. Physical chemistry, a term first coined by Mikhail Lomonosov in the eighteenth century, is the science that understands chemical systems in terms of the principles of physics such as equilibrium, velocity, and energy, to name a few. A chemical reaction is the phenomenon that transforms one chemical species into another. A chemical species is identified as a specific grouping of atoms joined together through interatomic forces or bonds, as they are called. Thus, a chemical reaction necessarily involves a rearrangement of atoms, that is, breaking of some of the existing chemical bonds and formation of some new ones. Breaking of chemical bonds requires energy to be spent while their formation releases energy.
