Physical chemistry is an interdisciplinary field that involves the application of physics to both microscopic and macroscopic phenomena in chemical settings by means of main concepts, principals and practices of thermodynamics, kinetics, statistical methods and quantum chemistry. Physical chemistry is mainly defined as a vast field of chemistry within which numerous sub-concepts are applicable. For instance, quantum mechanics is employed in physical chemistry to particulate and atomic experimentation and chemical interactions. Physical chemistry is also often termed as a macromolecule doctrine since most of the principals applied in physical chemistry constitute mainly of macromolecular concepts, for example, colloids. There are three main relationships which physical chemistry attempts to resolve. First, relationship is of the intermolecular forces with the physical properties of substances, for instance, surface tension within liquids, plasticity and tensile strength. Second, is effect of reaction kinetics upon the rate of reaction and third, is the association of the identity of ions upon the relative electrical conductivity of substances.

Even though the term physical chemistry has been used since 1752, the fundamentals of modern physical chemistry were placed in 1876. Since then, there are many sub-fields of physical chemistry such as thermochemistry, quantum chemistry, surface chemistry, spectroscopy, molecular modeling, photochemistry, chemical kinetics, electrochemistry, solid-state chemistry, materials science or materials engineering. Physical chemistry is an overlapping discipline with many other sub-fields of chemistry. Accordingly, both physical chemistry term and research papers often require knowledge of all other sub-fields of chemistry and not just physical chemistry itself.