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Dean–Stark Apparatus
upDean–Stark apparatus setup for an azeotrope with a solvent whose density is ''less than'' that of water: The Marcusson apparatus, Dean-Stark apparatus, Dean–Stark receiver, distilling trap, or Dean–Stark Head is a piece of laboratory glassware used in synthetic chemistry to collect water (or occasionally other liquid) from a reactor. It is used in combination with a reflux condenser and a distillation flask for the separation of water from liquids. This may be a continuous removal of the water that is produced during a chemical reaction performed at reflux temperature, such as in esterification reactions. The original setup by Julius Marcusson (invented in 1905) was refined by the American chemists Ernest Woodward Dean (1888–1959) and David Dewey Stark (1893–1979) in 1920 for determination of the water content in petroleum. Function left, A Dean–Stark apparatus in use; aluminium foil is used to reduce heat losses Two types of Dean–Stark traps exist – one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wild Arms 5
''Wild Arms 5'', released in Japan as , is a role-playing video game developed by Media.Vision and published by Sony Computer Entertainment for the PlayStation 2. It is the fifth and most recent main installment of the ''Wild Arms'' series. It was released in December 2006 in Japan, August 2007 in North America by Xseed Games, February 2008 in Europe by 505 Games and April 2008 in Australia by Xseed Games. The game celebrates the series' 10th anniversary by featuring cameo appearances of characters from the previous games. Gameplay Combat system During combat, the field is split into seven hexagonal sections, some of which may have special properties. The player and enemies can move to different hexagons during their turn. This time around, the party count is three instead of four. Dean's party members and enemies can act instantly when they move onto the next hexagonal platform. The Force meter returns from ''Wild Arms 4''. This meter increases as Dean's party members make ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiling Chip
A boiling chip, boiling stone, or porous bit anti-bumping granule is a tiny, unevenly shaped piece of substance added to liquids to make them boil more calmly. Boiling chips are frequently employed in distillation and heating. When a liquid becomes superheated, a speck of dust or a stirring rod can cause violent flash boiling. Boiling chips provide nucleation sites so the liquid boils smoothly without becoming superheated or bumping. Use Boiling chips should not be added to liquid that is already near its boiling point, as this could also induce flash boiling. Boiling chips should not be used when cooking unless they are suitable for food-grade applications. The structure of a boiling chip traps liquid while in use, meaning that they cannot be re-used in laboratory setups. They also don't work well under vacuum; if a solution is boiling under vacuum, it is best to constantly stir it instead. Materials Boiling chips are typically made of a porous material, such as alu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Le Chatelier's Principle
In chemistry, Le Chatelier's principle (pronounced or ) is a principle used to predict the effect of a change in conditions on chemical equilibrium. Other names include Chatelier's principle, Braun–Le Chatelier principle, Le Chatelier–Braun principle or the equilibrium law. The principle is named after French chemist Henry Louis Le Chatelier who enunciated the principle in 1884 by extending the reasoning from the Van 't Hoff relation of how temperature variations changes the equilibrium to the variations of pressure and what's now called chemical potential, and sometimes also credited to Karl Ferdinand Braun, who discovered it independently in 1887. It can be defined as: In scenarios outside thermodynamic equilibrium, there can arise phenomena in contradiction to an over-general statement of Le Chatelier's principle. Le Chatelier's principle is sometimes alluded to in discussions of topics other than thermodynamics. Thermodynamic statement Le Chatelier–Braun principl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Equilibrium
In a chemical reaction, chemical equilibrium is the state in which both the Reagent, reactants and Product (chemistry), products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the Thermodynamic system, system. This state results when the forward reaction proceeds at the same rate as the Reversible reaction, reverse reaction. The reaction rates of the forward and backward reactions are generally not zero, but they are equal. Thus, there are no net changes in the concentrations of the reactants and products. Such a state is known as dynamic equilibrium. It is the subject of study of ''equilibrium chemistry''. Historical introduction The Concept learning, concept of chemical equilibrium was developed in 1803, after Claude Louis Berthollet, Berthollet found that some chemical reactions are Reversible reaction, reversible. For any reaction mixture to exist at equilibrium, the reaction rate, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ester
In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distinctive functional group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well (e.g. amides), but not according to the IUPAC. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Lactones are cyclic carboxylic esters; naturally occurring lactones are mainly 5- and 6-membered ring lactones. Lactones contribute to the aroma of fruits, butter, cheese, vegetables like celery and other foods. Esters can be formed from oxoacids (e.g. esters of acetic acid, carbonic acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butanol
Butanol (also called butyl alcohol) is a four-carbon alcohol with a formula of C4 H9 OH, which occurs in five isomeric structures (four structural isomers), from a straight-chain primary alcohol to a branched-chain tertiary alcohol; all are a butyl or isobutyl group linked to a hydroxyl group (sometimes represented as BuOH, ''sec''-BuOH, i-BuOH, and ''t''-BuOH). These are 1-butanol, two stereoisomers of ''sec''-butyl alcohol, isobutanol and ''tert''-butyl alcohol. Butanol is primarily used as a solvent and as an intermediate in chemical synthesis, and may be used as a fuel. Biologically produced butanol is called biobutanol, which may be ''n''-butanol or isobutanol. Isomers The unmodified term ''butanol'' usually refers to the straight chain isomer with the alcohol functional group at the terminal carbon, which is also known as 1-butanol. The straight chain isomer with the alcohol at an internal carbon is ''sec''-butyl alcohol or 2-butanol. The branched isomer with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzoic Acid
Benzoic acid () is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. The benzoyl group is often abbreviated "Bz" (not to be confused with "Bn," which is used for benzyl), thus benzoic acid is also denoted as BzOH, since the benzoyl group has the formula –. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, which was for a long time its only source. Benzoic acid occurs naturally in many plants and serves as an intermediate in the biosynthesis of many secondary metabolites. Salts of benzoic acid are used as food preservatives. Benzoic acid is an important precursor for the industrial synthesis of many other organic substances. The salts and esters of benzoic acid are known as benzoates (). History Benzoic acid was discovered in the sixteenth century. The dry distillation of gum benzoin was first described by Nostradamus (1556), and then by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Regensburg
The University of Regensburg () is a public research university located in the city of Regensburg, Germany. The university was founded on 18 July 1962 by the Landtag of Bavaria as the fourth full-fledged university in Bavaria. Following groundbreaking in 1965, the university officially opened to students during the 1967–1968 winter semester, initially housing faculties in Law and Business Sciences and Philosophy. During the summer semester of 1968 the faculty of Theology was created. Currently, the University of Regensburg houses eleven faculties. The university actively participates in the European Union's SOCRATES programme as well as part of the Compostela-Group. Its most famous academic, Pope Benedict XVI, served as a professor there until 1977 and formally retained his chair in theology. History Attempts to establish a university in Regensburg had been advocated since the late 15th century. In 1487, Duke Albrecht IV of Bavaria and the Regensburg city council sent a pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula . It is a colorless, odorless, and Viscosity, viscous liquid that is Miscibility, miscible with water. Pure sulfuric acid does not occur naturally due to its Dehydration reaction, strong affinity to water vapor; it is Hygroscopy, hygroscopic and readily absorbs water vapor from the Atmosphere of Earth, air. Concentrated sulfuric acid is a strong oxidant with powerful dehydrating properties, making it highly corrosive towards other materials, from rocks to metals. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid but, to the contrary, dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is releas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetic Acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Historically, vinegar was produced from the third century BC and was likely the first acid to be produced in large quantities. Acetic acid is the second simplest carboxylic acid (after formic acid). It is an important Reagent, chemical reagent and industrial chemical across various fields, used primarily in the production of cellulose acetate for photographic film, polyvinyl acetate for wood Adhesive, glue, and synthetic fibres and fabrics. In households, diluted acetic acid is often used in descaling agents. In the food industry, acetic acid is controlled by the E number, food additive code E260 as an acidity regulator and as a condiment. In biochemistry, the acetyl group, derived from acetic acid, is funda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butanol
Butanol (also called butyl alcohol) is a four-carbon alcohol with a formula of C4 H9 OH, which occurs in five isomeric structures (four structural isomers), from a straight-chain primary alcohol to a branched-chain tertiary alcohol; all are a butyl or isobutyl group linked to a hydroxyl group (sometimes represented as BuOH, ''sec''-BuOH, i-BuOH, and ''t''-BuOH). These are 1-butanol, two stereoisomers of ''sec''-butyl alcohol, isobutanol and ''tert''-butyl alcohol. Butanol is primarily used as a solvent and as an intermediate in chemical synthesis, and may be used as a fuel. Biologically produced butanol is called biobutanol, which may be ''n''-butanol or isobutanol. Isomers The unmodified term ''butanol'' usually refers to the straight chain isomer with the alcohol functional group at the terminal carbon, which is also known as 1-butanol. The straight chain isomer with the alcohol at an internal carbon is ''sec''-butyl alcohol or 2-butanol. The branched isomer with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon with the chemical formula , often abbreviated as , where Ph stands for the phenyl group. It is a colorless, water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...-insoluble liquid with the odor associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group by a single bond. As such, its systematic IUPAC nomenclature of organic chemistry, IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent. As the solvent in some types of paint thinner, permanent markers, contact cement and certain types of glue, toluene is sometimes used as a recreational inhalant and has the potential of causin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
