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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.
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
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.
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
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.
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