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Phlogiston
The phlogiston theory, a superseded scientific theory, postulated the existence of a fire-like element dubbed phlogiston () contained within combustible bodies and released during combustion. The name comes from the Ancient Greek (''burning up''), from (''flame''). The idea of a substance was first proposed in 1667 by Johann Joachim Becher and later put together more formally in 1697 by Georg Ernst Stahl. Phlogiston theory attempted to explain chemical processes such as combustion and rusting, now collectively known as oxidation. The theory was challenged by the concomitant mass increase and was abandoned before the end of the 18th century following experiments by Antoine Lavoisier in the 1770s and by other scientists. Phlogiston theory led to experiments that ultimately resulted in the identification (), and naming (1777), of oxygen by Joseph Priestley and Antoine Lavoisier, respectively. Theory Phlogiston theory states that ''phlogisticated'' substances contain phlo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Priestley
Joseph Priestley (; 24 March 1733 – 6 February 1804) was an English chemist, Unitarian, Natural philosophy, natural philosopher, English Separatist, separatist theologian, Linguist, grammarian, multi-subject educator and Classical liberalism, classical liberal Political philosophy, political theorist. He published over 150 works, and conducted experiments in several areas of science. Priestley is credited with his independent discovery of oxygen by the thermal decomposition of mercuric oxide, having isolated it in 1774. During his lifetime, Priestley's considerable scientific reputation rested on his invention of carbonated water, his writings on electricity, and his discovery of several "airs" (gases), the most famous being what Priestley dubbed "dephlogisticated air" (oxygen). Priestley's determination to defend phlogiston theory and to reject what would become the chemical revolution eventually left him isolated within the scientific community. Priestley's science was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antoine Lavoisier
Antoine-Laurent de Lavoisier ( ; ; 26 August 17438 May 1794), When reduced without charcoal, it gave off an air which supported respiration and combustion in an enhanced way. He concluded that this was just a pure form of common air and that it was the air itself "undivided, without alteration, without decomposition" which combined with metals on calcination. After returning from Paris, Priestley took up once again his investigation of the air from mercury calx. His results now showed that this air was not just an especially pure form of common air but was "five or six times better than common air, for the purpose of respiration, inflammation, and ... every other use of common air". He called the air dephlogisticated air, as he thought it was common air deprived of its phlogiston. Since it was therefore in a state to absorb a much greater quantity of phlogiston given off by burning bodies and respiring animals, the greatly enhanced combustion of substances and the greater ease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcination
Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition. The root of the word calcination refers to its most prominent use, which is to remove carbon from limestone (calcium carbonate) through combustion to yield calcium oxide (quicklime). This calcination reaction is CaCO3(s) → CaO(s) + CO2(g). Calcium oxide is a crucial ingredient in modern cement, and is also used as a chemical flux in smelting. Industrial calcination generally emits carbon dioxide (). A calciner is a steel cylinder that rotates inside a heated furnace and performs indirect high-temperature processing (550–1150 °C, or 1000–2100 °F) within a controlled atmosphere. Etymology The process of calcination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georg Ernst Stahl
Georg Ernst Stahl (22 October 1659Stahl's date of birth is often given erroneously as 1660. The correct date is recorded in the parish register of St. John's church, Ansbach. See – 24 May 1734) was a German chemist, physician and philosopher. He was a supporter of vitalism, and until the late 18th century his works on phlogiston were accepted as an explanation for chemical processes.Ku-ming Chang (2008)"Stahl, Georg Ernst", ''Complete Dictionary of Scientific Biography'', Vol. 24, from Cengage Learning Raised as a son to a Lutheran pastor, he was brought up in a very pious and religious household. From an early age he expressed profound interest in chemistry, by age 15 mastering a set of university lecture notes on chemistry and eventually a difficult treatise by Johann von Löwenstern-Kunckel, Johann Kunckel. He had two wives, who both died from puerperal fever in 1696 and 1706. He also had a son Johnathan and a daughter who died in 1708. He continued to work and publish foll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calx
Calx is a substance formed from an ore or mineral that has been heated. Calx, especially of a metal, is now understood to be an oxide. The term is also sometimes used in older texts on artists' techniques to mean calcium oxide. According to the obsolete phlogiston theory, the calx was the true elemental substance that was left after phlogiston was driven out of it in the process of combustion. __TOC__ Etymology Calx is Latin for chalk or limestone, from the Greek χάλιξ (''khaliks'', “pebble”). (It is not to be confused with the Latin homonym meaning heelbone (or calcaneus in modern medical Latin), which has an entirely separate derivation.) In popular culture * UK electronic music artist Aphex Twin Richard David James (born 18 August 1971), known professionally as Aphex Twin, is a British musician, composer and DJ active in electronic music since 1988. His idiosyncratic work has drawn on many styles, including techno, ambient music, ambi ... named four of his tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superseded Scientific Theories
This list includes well-known general theories in science and pre-scientific natural philosophy and natural history that have since been superseded by other scientific theories. Many discarded explanations were once supported by a scientific consensus, but replaced after more empirical information became available that identified flaws and prompted new theories which better explain the available data. Pre-modern explanations originated before the scientific method, with varying degrees of empirical support. Some scientific theories are discarded in their entirety, such as the replacement of the phlogiston theory by energy and thermodynamics. Some theories known to be incomplete or in some ways incorrect are still used. For example, Newtonian classical mechanics is accurate enough for practical calculations at everyday distances and velocities, and it is still taught in schools. The more complicated relativistic mechanics must be used for long distances and velocities nearing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniel Rutherford
Daniel Rutherford (3 November 1749 – 15 November 1819) was a Scottish physician, chemist and botanist who is known for the isolation of nitrogen in 1772. Life Rutherford was born on 3 November 1749, the son of Anne Mackay and Professor John Rutherford (1695–1779). He began college at the age of 16 at Mundell's School on the West Bow close to his family home, and then studied medicine under William Cullen and Joseph Black at the University of Edinburgh, graduating with a doctorate (MD) in 1772. From 1775 to 1786 he practiced as a physician in Edinburgh. On 12 April 1782 Rutherford was one of the founding members of the Harveian Society of Edinburgh and served as President in 1787. In 1783 he was a joint founder of the Royal Society of Edinburgh. In 1784 he was elected a member of the Aesculapian Club. At this time he lived at Hyndford Close on the Royal Mile a house he (or his father) had purchased from Dunbar Douglas, 4th Earl of Selkirk He was a professor of b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Heinrich Pott
Johann Heinrich Pott (6 October 1692 – 29 March 1777) was a Prussian physician, chemist, and a glass and porcelain technologist. He is considered a pioneer of pyrochemistry. He examined the elements bismuth and manganese apart from attempting improvements to glass and porcelain production. Biography Pott was born in Halberstadt, son of the royal councillor Johann Andreas Pott (1662–1729) and Dorothea Sophia daughter of Andreas Machenau. He studied at the cathedral school in Halberstadt and Francke's pedagogium before studying theology at the University of Halle. He then shifted to study medicine and chemistry under Georg Ernst Stahl. In 1713 he studied assaying at Mansfield under mining master Lages. He spent two years along with two of his brothers as travelling evangelists for the Community of True Inspiration but he left the sect in 1715 and returned to study chemistry at Halle, receiving a doctorate in 1716 on sulfur under Friedrich Hoffmann. He worked as a physician ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. It is a common element in the universe, estimated at Abundance of the chemical elements, seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element chemical bond, bond to form N2, a colourless and odourless diatomic molecule, diatomic gas. N2 forms about 78% of Atmosphere of Earth, Earth's atmosphere, making it the most abundant chemical species in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772 and independently by Carl Wilhelm Scheele and Henry Cavendish at about the same time. The name was suggested by French chemist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulphate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid. Spelling "Sulfate" is the spelling recommended by IUPAC, but "sulphate" was traditionally used in British English. Structure The sulfate anion consists of a central sulfur atom surrounded by four equivalent oxygen atoms in a tetrahedral arrangement. The symmetry of the isolated anion is the same as that of methane. The sulfur atom is in the +6 oxidation state while the four oxygen atoms are each in the −2 state. The sulfate ion carries an overall charge of −2 and it is the conjugate base of the bisulfate (or hydrogensulfate) ion, , which is in turn the conjugate base of , sulfuric acid. Organic sulfate esters, such as dimethyl sulfate, are covalent compounds and esters of sulfuric acid. The tetrahedral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
