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Branches of Chemistry

Chemistry can be grouped into five major branches. These are Organic Chemistry, Inorganic Chemistry, Physical Chemistry, Analytical Chemistry, and Biochemistry.

This is the branch of chemistry that studies chemical compounds that contain the element carbon, and carbon-hydrogen bonds (C-H). Organic chemists (chemists who specialize in organic chemistry) seek to understand the structure, properties, and the kind of reactions such compounds undergo. With this understanding, they can identify and classify the various naturally occurring organic compounds and also create organic compounds with desired properties and functions.

Organic chemistry is in the heart of such industries as the pharmaceutical, rubber, fuel, plastic, cosmetics, detergent, dyestuffs, agrichemicals, and coatings industries.  

This branch of chemistry studies the reactions and properties of all chemical compounds that do not have the C-H bonds. In other words, inorganic chemistry studies compounds that are not organic.  Inorganic compounds include minerals found in the earth's crust and non-living matter.

This branch of chemistry studies the physical properties of chemical compounds using laws and concepts of physics, such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics and dynamics.

Physical properties of chemical compounds include, temperature, pressure, volume, electrical conductivity, plasticity, tensile strength, surface tension in liquids, solubility, viscosity, boiling point, melting point, and color.

Using mathematical models and formulas, physical chemists (specialists in physical chemistry) are able to quantify the physical properties of chemical substances, and are also able to determine the effect certain phenomena would have on the physical properties of chemical substances.

This branch of chemistry deals with the separation, identification and quantification of chemical substances (analytes) in a given sample. In a simple way, the knowledge of analytical chemistry enables chemists to determine the chemical substances that could be present in a given material.

Analytical chemistry involves two aspects: qualitative analysis and quantitative analysis. Qualitative analysis involves processes that are carried out to identify a chemical substance in a given sample; while quantitative analysis involves finding out the concentration or the amount of the substance in the sample.

To effectively carry out the identification and quantification of chemical substances to a high degree of accuracy, several chemical and physical methods have been developed.

Purely chemical methods were developed in the nineteenth century and are known as classical methods (also called wet chemistry methods). Chemical or classical methods involve the use of chemical substances of known composition to identify the analyte (chemical substance being investigated). Analytes can also be identified by odor, color, boiling point, or melting point.  

Quantitative analyses using classical methods include titrimetry, where the concentration of the analyte is determined by the volume of a reagent required to completely react with it, and gravimetry, where the amount of the analyte present is determined by the mass of product obtained from a chemical reaction involving the chemical sample and a suitable chemical compound.

Classical methods are precise and highly accurate; however, they have some serious shortcomings. They require adequate quantity of the sample and the concentration of the analyte in the sample must not be lower than 0.1 percent. They also require trained chemists to carry them out, who may have to prepare the standard solutions to be used.

Physical methods for identifying and quantifying chemical substances are based on the amount of light absorbed or emitted by the analyte, or on the strength of an electrical signal produced by the analyte at an electrode. Physical methods are also called instrumental methods because they rely on the use of machines to determine the physical quantities of analytes.

Physical methods are not as accurate or precise as classical methods, but they require little sample and can determine concentration of analytes that are below 0.1 percent of the sample. They also produce faster results than classical methods. Instrumental methods are gradually replacing many classical methods in today’s analytical chemistry as more powerful analytical machines are being invented.

Analytical chemistry has wide applications in environmental analysis, forensics, clinical analysis, materials analysis, and bioanalysis.   

This is the branch of chemistry that studies the structure, composition, and chemical reactions of chemical components of living systems (plants, insects, viruses, microorganisms, and mammals) to understand how and why chemical reactions occur in them.

Biochemistry combines biology with organic, inorganic, and physical chemistry and deals with issues such as the fundamental changes that take place in diseases, the chemical basis of heredity, and how living things derive energy from foods.

Biochemistry has wide applications in medicine, veterinary medicine, dentistry, food science, and agriculture. It also finds application in physiology, pharmacology, clinical chemistry, and microbiology where biochemists (scientists that study biochemistry) may study the mechanism of a drug action; research viral activities; study the mechanism of organ functioning; or apply chemical concepts, procedures, and techniques to investigate the diagnosis and treatment of disease and evaluation of health.