Chemistry

Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties.[1][2] Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds.

Chemistry is sometimes called "the central science" because it connects physics with other natural sciences such as geology and biology.[3][4] Chemistry is a branch of physical science but distinct from physics.[5]

The etymology of the word chemistry has been much disputed.[6] The genesis of chemistry can be traced to certain practices, known as alchemy, which had been practiced for several millennia in various parts of the world, particularly the Middle East.[7]

Theory

Laboratory, Institute of Biochemistry, University of Cologne.

Traditional chemistry starts with the study of elementary particles, atoms, molecules,[8] substances, metals, crystals and other aggregates of matter. in solid, liquid, and gas states, whether in isolation or combination. The interactions, reactions and transformations that are studied in chemistry are a result of interaction either between different chemical substances or between matter and energy. Such behaviors are studied in a chemistry laboratory using various forms of laboratory glassware.

A chemical reaction is a transformation of some substances into one or more other substances.[9] 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.

Energy and entropy considerations are invariably important in almost all chemical studies. Chemical substances are classified in terms of their structure, phase as well as their chemical compositions. They can be analyzed using the tools of chemical analysis, e.g. spectroscopy and chromatography. Scientists engaged in chemical research are known as chemists.[10] Most chemists specialize in one or more sub-disciplines.

History

Main article: History of chemistry

See also: Alchemy, Timeline of chemistry, and Nobel Prize in Chemistry

Ancient Egyptians pioneered the art of synthetic "wet" chemistry up to 4,000 years ago.[11] By 1000 BC ancient civilizations were using technologies that formed the basis of the various branches of chemistry such as; extracting metal from their ores, making pottery and glazes, fermenting beer and wine, making pigments for cosmetics and painting, extracting chemicals from plants for medicine and perfume, making cheese, dying cloth, tanning leather, rendering fat into soap, making glass, and making alloys like bronze.

Democritus' atomist philosophy was later adopted by Epicurus (341–270 BCE).

The genesis of chemistry can be traced to the widely observed phenomenon of burning that led to metallurgy—the art and science of processing ores to get metals (e.g. metallurgy in ancient India). The greed for gold led to the discovery of the process for its purification, even though the underlying principles were not well understood—it was thought to be a transformation rather than purification. Many scholars in those days thought it reasonable to believe that there exist means for transforming cheaper (base) metals into gold. This gave way to alchemy and the search for the Philosopher's Stone which was believed to bring about such a transformation by mere touch.[12]

Greek atomism dates back to 440 BC, as what might be indicated by the book De Rerum Natura (The Nature of Things)[13] written by the Roman Lucretius in 50 BC.[14] Much of the early development of purification methods is described by Pliny the Elder in his Naturalis Historia.

A tentative outline is as follows:

Egyptian alchemy [3,000 BCE – 400 BCE], formulate early "element" theories such as the Ogdoad.

Greek alchemy [332 BCE – 642 CE], the Macedonian king Alexander the Great conquers Egypt and founds Alexandria, having the world's largest library, where scholars and wise men gather to study.

Islamic alchemy [642 CE – 1200], the Muslim conquest of Egypt; development of alchemy by Jābir ibn Hayyān, al-Razi and others; Jābir modifies Aristotle's theories; advances in processes and apparatus.[15]

European alchemy [1300 – present], Pseudo-Geber builds on Arabic chemistry.[citation needed] From the 12th century, major advances in the chemical arts shifted from Arab lands to western Europe.[15]

Chemistry [1661], Boyle writes his classic chemistry text The Sceptical Chymist.

Chemistry [1787], Lavoisier writes his classic Elements of Chemistry.

Chemistry [1803], Dalton publishes his Atomic Theory.

Chemistry [1869], Dmitri Mendeleev presented his Periodic table being the framework of the modern chemistry

The earliest pioneers of Chemistry, and inventors of the modern scientific method,[16] were medieval Arab and Persian scholars. They introduced precise observation and controlled experimentation into the field and discovered numerous Chemical substances.[17][verification needed]

"Chemistry as a science was almost created by the Muslims; for in this field, where the Greeks (so far as we know) were confined to industrial experience and vague hypothesis, the Saracens introduced precise observation, controlled experiment, and careful records. They invented and named the alembic (al-anbiq), chemically analyzed innumerable substances, composed lapidaries, distinguished alkalis and acids, investigated their affinities, studied and manufactured hundreds of drugs. Alchemy, which the Muslims inherited from Egypt, contributed to chemistry by a thousand incidental discoveries, and by its method, which was the most scientific of all medieval operations."[17]

The most influential Muslim chemists were Jābir ibn Hayyān (Geber, d. 815), al-Kindi (d. 873), al-Razi (d. 925), al-Biruni (d. 1048) and Alhazen (d. 1039).[18] Their works became more widely known in Europe in the twelfth and thirteenth centuries, beginning with the Latin translation of Jābir’s Kitab al-Kimya in 1144. The contribution of Indian alchemists and metallurgists in the development of chemistry was also quite significant.[19]

Antoine-Laurent de Lavoisier is considered the "Father of Modern Chemistry".[20]

For some practitioners, alchemy was an intellectual pursuit, over time, they got better at it. 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 René 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.[21]

Chemistry indeed came of age when Antoine Lavoisier (1743–1794), developed the theory of Conservation of mass in 1783; and the development of the Atomic Theory by John Dalton around 1800. The Law of Conservation of Mass resulted in the reformulation of chemistry based on this law[citation needed] and the oxygen theory of combustion, which was largely based on the work of Lavoisier. Lavoisier's fundamental contributions to chemistry were a result of a conscious effort[citation needed] to fit all experiments into the framework of a single theory.

Lavoisier established the consistent use of the chemical balance, used oxygen to overthrow the phlogiston theory, and developed a new system of chemical nomenclature and made contribution to the modern metric system. Lavoisier also worked to translate the archaic and technical language of chemistry into something that could be easily understood by the largely uneducated masses, leading to an increased public interest in chemistry. All these advances in chemistry led to what is usually called the chemical revolution. The contributions of Lavoisier led to what is now called modern chemistry—the chemistry that is studied in educational institutions all over the world. It is because of these and other contributions that Antoine Lavoisier is often celebrated as the "Father of Modern Chemistry".[22] The later discovery of Friedrich Wöhler that many natural substances, organic compounds, can indeed be synthesized in a chemistry laboratory also helped the modern chemistry to mature from its infancy.[23]

The discovery of the chemical elements has a long history from the days of alchemy and culminating in the discovery of the periodic table of the chemical elements by Dmitri Mendeleev (1834–1907)[24] and later discoveries of some synthetic elements.

Jöns Jacob Berzelius, Joseph Priestley, Humphry Davy, Linus Pauling, Gilbert N. Lewis, Josiah Willard Gibbs, Robert Burns Woodward, and Fritz Haber also made notable contributions.

The year 2011 was declared by the United Nations as the International Year of Chemistry.[25] It was an initiative of the International Union of Pure and Applied Chemistry , and of the United Nations Educational, Scientific, and Cultural Organization and involves chemical societies, academics, and institutions worldwide and relied on individual initiatives to organize local and regional activities.