Chemistry (from Egyptian kēme (chem), meaning "earth"[1]) is the science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions.[2] Historically, modern chemistry evolved out of alchemy following the chemical revolution (1773). Chemistry is a physical science related to studies of various atoms, molecules, crystals and other aggregates of matter whether in isolation or combination, which incorporates the concepts of energy and entropy in relation to the spontaneity of chemical processes.
Disciplines within chemistry are traditionally grouped by the type of matter being studied or the kind of study. 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).
Contents
- 1 Overview
- 2 History
- 3 Etymology
- 4 Definitions
- 5 Basic concepts
- 5.1 Atom
- 5.2 Element
- 5.3 Compound
- 5.4 Substance
- 5.5 Molecule
- 5.6 Mole
- 5.7 Ions and salts
- 5.8 Acidity and basicity
- 5.9 Phase
- 5.10 Chemical bond
- 5.11 Chemical reaction
- 5.12 Energy
- 5.13 Chemical laws
- 6 Subdisciplines
- 7 Chemical industry
- 8 References
- 9 Further reading
- 9.1 Popular reading
- 9.2 Introductory undergraduate text books
- 9.3 Advanced undergraduate-level or graduate text books
- 10 Professional societies
- 11 See also
- 12 External links
Etymology
Main article: Chemistry (etymology)
The word chemistry comes from the earlier study of alchemy, which is basically the quest to make gold from earthen starting materials. As to the origin of the word "alchemy" the question is a debatable one; it certainly can be traced back to the Greeks, and some, following E. Wallis Budge, have also asserted Egyptian origins. Alchemy, generally, derives from the old French alkemie from the Arabic كيمياء al-kīmiyā' - "the art of transformation". The Arabs borrowed the word "kimia" from the Greeks when they conquered Alexandria in the year 642 AD. A tentative outline is as follows:
1. Egyptian alchemy [3,000 BCE – 400 BCE], formulate early "element" theories such as the Ogdoad.
2. Greek alchemy [332 BCE – 642 CE], the Greek king Alexander the Great conquers Egypt and founds Alexandria, having the world's largest library, where scholars and wise men gather to study.
3. Arabian alchemy [642 CE – 1200], the Arabs take over
4. European alchemy [1300 – present], Pseudo-Geber builds on Arabic chemistry
5. Chemistry [1661], Boyle writes his classic chemistry text The Sceptical Chymist
6. Chemistry [1787], Lavoisier writes his classic Elements of Chemistry
7. Chemistry [1803], Dalton publishes his Atomic Theory
Thus, an alchemist was called a 'chemist' in popular speech, and later the suffix "-ry" was added to this to describe the art of the chemist as "chemistry".
