What is Physical Chemistry | Definition, Applications

Definition of Physical Chemistry

Physical chemistry is the study of how matter behaves on a molecular and atomic level and how chemical reaction occur. It use d concept from physics to understand how chemistry works.

physical chemistry

For example-: Figuring out how atom move and interact with each other or why some liquid including water turn into vapor at high temperature. Physical chemists try to understand these phenomena at very small scale. On the level of atoms and molecules to derive about how chemical reaction work. And what gives specific material their own unique properties.

Relationships That Physical Chemistry Strives To Resolve Include The Effects of

  1. Intermolecular forces that act upon the physical properties of materials (plasticity, tensile strength, surface tension in liquids).
  2. Reaction kinetics on the rate of a reaction.
  3. The identity of ions and the electrical conductivity of materials.
  4. Surface science and electrochemistry of cell membranes.
  5. Interaction of one body with another in terms of quantities of heat and work called thermodynamics.
  6. Transfer of heat between a chemical system and its surroundings during change of phase or chemical reaction taking place called thermochemistry.
  7. Study of colligative properties of number of species present in.
  8. Reactions of electrochemical cells.

Physical chemistry, branch of chemistry concerned with interactions and transformations of materials. Unlike other branches, it deals with the principles of physics underlying all chemical interactions. (e.g., gas laws), seeking to measure, correlate, and explain the quantitative aspects ofreactions.

Quantum mechanics has clarified much for physical chemistry by modeling the smallest particles ordinarily dealt with in the field, atoms and molecules. Enabling theoretical chemists to use computers and sophisticated mathematical techniques to understand the chemical behavior of matter.

Chemical thermodynamics deals with the relationship between heat and other forms of chemical energy, kinetics with ch emical reaction rates. Subdisciplines of physical chemistry include electrochemistry, photochemistry (see photochemical reaction), surface chemistry and catalysis.

History of Physical Chemistry

history of physical chemistry

The term “physical chemistry” was coined by Mikhail Lomonosov in 1752, when he presented a lecture course entitled “A Course in True Physical Chemistry” before the students of Petersburg University. In the preamble to these lectures he gives the definition: “Physical chemistry is the science that must explain under provisions of physical experiments the reason for what is happening in complex bodies through chemical operations”.

Modern physical chemistry originated in the 1860s to 1880s with work on chemical thermodynamics, electrolytes in solutions, chemical kinetics and other subjects. One milestone was the publication in 1876 by Josiah Willard Gibbs of his paper, On the Equilibrium of Heterogeneous Substances. This paper introduced several of the cornerstones of physical chemistry, such as Gibbs energy, chemical potentials, and Gibbs’ phase rule.

The first scientific journal specifically in the field of physical chemistry was the German journal, Zeitschrift für Physikalische Chemie, founded in 1887 by Wilhelm Ostwald and Jacobus Henricks van’t Hoff. Together with Svante August Arrhenius, these were the leading figures in physical chemistry in the late
19th century and early 20th century. All three were awarded the Nobel Prize in Chemistry between 1901–1909.

Developments in the following decades include the application of statistical mechanics to chemical systems. And work on colloids and surface chemistry, where Irving Langmuir made many contributions. Another important step was the development of quantum mechanics into quantum chemistry from the 1930s. Where Linus Pauling was one of the leading names.

Theoretical developments have gone hand in hand with developments in experimental methods, where the use of different forms of spectroscopy, such as infrared spectroscopy, microwave spectroscopy, electron paramagnetic resonance. And nuclear magnetic resonance spectroscopy, is probably the most important 20th century development.

Further development in physical chemistry may be attributed to discoveries in nuclear chemistry, especially in isotope separation (before and during World War II), more recent discoveries in astrochemistry, as well as the development of calculation algorithms in the field of “additive physicochemical properties” (practically all physicochemical properties, such as boiling point, critical point, surface tension, vapor pressure, etc. (can be precisely calculated from chemical structure alone, even if the chemical molecule remains synthesized).

Applications of Physical Chemistry

applications of physical chemistry

Physical Chemistry researchers are revolved around understanding the physical properties of particles and iotas. The way substance reactions work, and what these properties reveal. Their work incorporates dismembering materials, making procedures to test and depict the properties of materials, making hypotheses about these properties, and finding the potential use of the materials.

Using refined instrumentation and equipment has constantly been a basic piece of physical science. Most physical science labs are stacked with informative instruments. Which can join lasers, mass spectrometers, nuclear alluring resonation, and electron amplifying focal point. Physical experimental specialists’ disclosures rely on upon appreciation substance properties and depicting their behavior using speculations of material science and numerical counts .

Physical experimental specialists foresee properties and reactions of chemicals, then test and refine those predications. They use logical examination and bits of knowledge on enormous datasets, from time to time with a considerable number of data centers, to reveal covered information about blends, materials, and techniques . They may moreover lead entertainments, making exploratory conditions that envision how blends will react after some time.

Starting late, more physical researchers have found homes in the creating fields of materials science and sub-nuclear exhibiting. Where their aptitudes in separating and anticipating the behavior of physical properties have empowering new applications. By joining the numerical inflexible nature of physical science with the sensibility of new materials and new applications. The field of physical science is stretching out in new and invigorating ways.

Physical Chemistry investigative specialists work in a collection of different areas, however their common target is to discover, test, and appreciate the crucial physical characteristics of a material be it solid, liquid, or gas.Exactness and trustworthiness make their work to some degree like exploratory science, however physical investigative specialists in like manner push the importance of applying data of math and material science to develop a cautious appreciation of the material [6,7].

Physical investigative specialists generally have a strong enthusiasm about how things work at the atomic level. And acknowledge working with lab instrumentation and machines. Various are pulled in to the way that physical science methodology resembles those of building. And various experimental specialists acknowledge using their understanding and love for science to make disclosures.

A physical science lab is depicted by the broad machines and propelled instrumentation these scientists use to test and separate materials . Various who work in the lab say their time is isolated between working at the seat and working at their work ranges doing estimations and studying data.

Physical experimental specialists who go into organization in like manner contribute vitality coordinating distinctive scientists, evaluating division needs and goals, and meeting with business boss in their associations.

Physical Chemistry applies material science and math to issues that interest exploratory specialists, researchers, and creators, Physical researchers use speculative creates and experimental figuring’s to grasp manufactured properties and delineate the behaviour of nuclear and solidified matter.

Their work incorporates controls of data furthermore materials . The specialty really clicks for a couple understudies when they first study the relationship amongst math and science, making sense of how they can use math as an able instrument to suspect properties of chemicals .

A by and large new advancement that similarly joins science, math, and material science is the district of nuclear proliferation. Physical researchers made sub-nuclear proliferation gadgets that are getting the chance to be fundamental to look at in
each part of science .

Specialists who perceive how to use such gadgets are depended upon to be essential to the improvement of this distinguishing strength. See their work as interdisciplinary Physical science has usually given understudies far reaching get ready and arranged them to work in a grouping of test jobs .

A multifaceted, interdisciplinary perspective is basic to the field. Various physical logical specialists finally act as interpretive experimental specialists and acknowledge responsibility for the advanced methodical work that pushes the field.

Analysts, who work for an association that makes radiance care things, for occasion, may work in physical or consistent science, coordinating associated and key surfactant research for thing change applications. Such work incorporates measuring and perception the social affair of particles.

The research performed by physical chemists is an increasingly small part of industrial research. Accordingly, fewer physical chemists are being hired by industry and government labs.

Still, physical chemistry provides broad training and positions students to work in a variety of scientific careers. Such as: Emerging fields of materials science and molecular modeling. Combining the traditional mathematical rigor of physical chemistry with the practicality of these fields offers new and exciting possibilities.

Branches of Physical Chemistry

There are several branches of Physical chemistry that holds vital importance in this subject. Every student must be familiar with these branches only then you can have mastery over the subject. Below you can read in brief about different branches of chemistry.


Thermodynamics is a branch of physical chemistry. It deals with the relation between heat, work, energy and
temperature. Thermodynamics study dynamic nature of heat, or we can say the transfer of energy from place to place and change in its form. The main concept here is that heat is a form of energy which is equal to a specific amount of mechanical work.

Chemical Kinetics

The second branch of physical chemistry which I am discussing with you right now is Chemical kinetics. This branch of physical Chemistry also known as Reaction kinetics. In this students study about the rate of chemical processes. This branch of physical chemistry investigates the influence of various experimental conditions on a chemical reaction. This helps to find out chemical mechanism and transition states. It also helps in defining the characteristics of the chemical reaction.


This branch of physical chemistry studies the chemical effects of light. Usually, the term Photochemistry defines a chemical reaction occurred due to absorption of UV, Visible light or Infrared radiations.
When we talk about nature, Photochemistry has a vital role because it forms the basis of photosynthesis, the formation of vitamin D and vision. Photochemical reactions are different from other reactions. Photochemical reactions create high energy that is not possible to generate with heat. This makes to cross large activation barriers in the least time.

Quantum Chemistry

This is a branch of Physical chemistry that focus on the applications of quantum mechanics in various physical models and different experiments of chemistry. This branch is also famous with the name quantum mechanics.


This branch of physical chemistry studies the movement of electrons due to various chemical processes. Movement of electrons is known as electricity. Electricity is generated from the displacement of electrons from one element to another in a reaction known as a redox reaction.

This reaction is also famous with the name oxidation-reduction reaction. This reaction involves the change of
state of single or more elements. On losing an electron by a substance, oxidation state increases, and it is called as oxidized. On gaining the electron by a substance, its oxidation state gets reduce

Biophysical Chemistry

This branch of physical chemistry involves the concepts of physics and chemistry together to research on biological systems. In this research, scientists seek information on the various phenomenon in biological systems. These systems can be molecules or supra molecules of a bio system.

Material Science

This field is also popular with the name material science and engineering. This field is related to the discovery and designing of new materials which are specifically solid in nature. The origin of material science was back in the age of enlightenment. During this period researchers and scientists utilized their analytical knowledge of chemistry, engineering and physics to understand the old age metallurgy and mineralogy.


Spectroscopy is also a branch of physical chemistry. It deals with the interaction of electromagnetic radiations with the matter. This branch came into existence with the study of dispersion of white light through a glass prism according to the wavelength. After a few years, researchers also started studying radioactive energy interaction in the electromagnetic spectrum.

Physical Organic Chemistry

The name was first suggested by Louis Hammett in the year 1940. This branch of physical chemistry is closely
associated with organic chemistry. It focuses on the relationship between chemical structures and reactivity. Here in this branch of physical chemistry scientists use tools of physical chemistry. These tools allow to study different organic molecules.

The research has some focus points which are relative chemical stabilities, reactive intermediates, transition states, starting materials, a product of chemical reactions non covalent aspects of solvation and molecular interactions. These aspects influence chemical reactivity. Studies of these frameworks indicate how changes of structure in liquid or solid states make an impact on the reaction mechanism.

Material Chemistry

This branch of physical chemistry also sometimes known as solid state chemistry. It is a study of structure, synthesis and different property of solid materials. This branch has overlap with thermodynamics, mineralogy, crystallography, metallurgy, ceramics, and electronics with a synthesis of unique materials and their features. Solids are studied under two forms one is crystalline and other is amorphous. This depends on the arrangement of constituent particles.

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