Chemistry, Chemistry

Modern chemistry evolved out of alchemy following the chemical revolution (1773).

These include inorganic chemistry, the study of inorganic matter; organic chemistry, the study of organic matter; biochemistry, the study of substances found in biological organisms; physical chemistry, the energy related studies of chemical systems at macro, molecular and submolecular scales; analytical chemistry, the analysis of material samples to gain an understanding of their chemical composition and structure. Many more specialized disciplines have emerged in recent years, e.g. neurochemistry the chemical study of the nervous system (see subdisciplines).

Traditional chemistry involves study of interactions between substances in a chemistry laboratory using various forms of laboratory glassware., Institute of Biochemistry, University of Cologne A chemical reaction is a transformation of some substances into one or more other substances. IUPAC Gold Book Definition It can be symbolically depicted through a chemical equation. The number of atoms on the left and the right in the equation for a chemical transformation is most often equal. The nature of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws.

At these levels, it is often called "general chemistry" which is an introduction to a wide variety of fundamental concepts that enable the student to acquire tools and skills useful at the advanced levels, whereby chemistry is invariably studied in any of its various sub-disciplines. Scientists, engaged in chemical research are known as chemists. California Occupational Guide Number 22: Chemists [2] Most chemists specialize in one or more sub-disciplines.

Will Durant (1935): Our Oriental Heritage: Simon & Schuster: The emergence of chemistry in Europe was primarily due to the recurrent incidence of the plague and blights there during the so called Dark Ages. This gave rise to a need for medicines. It was thought that there exists a universal medicine called the Elixir of Life that can cure all diseases, but like the Philosopher's Stone, it was never found.

Paracelsus (1493-1541), for example, rejected the 4-elemental theory and with only a vague understanding of his chemicals and medicines, formed a hybrid of alchemy and science in what was to be called iatrochemistry . Similarly, the influences of philosophers such as Sir Francis Bacon (1561-1626) and Ren Descartes (1596-1650), who demanded more rigor in mathematics and in removing bias from scientific observations, led to a scientific revolution. In chemistry, this began with Robert Boyle (1627-1691), who came up with an equation known as Boyle's Law about the characteristics of gaseous state.

Generally it refers to a system for naming chemical compounds. Earlier in the history of chemistry substances were given name by their discoverer, which often led to some confusion and difficulty. However, today the IUPAC system of chemical nomenclature allows chemists to specify by name specific compounds amongst the infinite variety of possible chemicals. The standard nomenclature of chemical substances is set by the International Union of Pure and Applied Chemistry (IUPAC). There are well-defined systems in place for naming chemical species. Organic compounds are named according to the organic nomenclature system. IUPAC Nomenclature of Organic Chemistry [8] Inorganic compounds are named according to the inorganic nomenclature system. IUPAC Provisional Recommendations for the Nomenclature of Inorganic Chemistry (2004) [9] In addition the Chemical Abstracts Service has devised a method to index chemical substance. In this scheme each chemical substance is identifiable by a numeric number known as CAS registry number.

Molarity is the common unit used to express the concentration of a solution in physical chemistry.

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