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Germain Hess
Germain Henri Hess (russian: Герман Иванович Гесс, German Ivanovich Gess; 7 August 1802 – 30 November 1850) was a Swiss-Russian chemist and doctor who formulated Hess's law, an early principle of thermochemistry. Early life and education Hess was born on 26 July (7 August) in Geneva, Switzerland. His father was an artist and in 1805 moved the family to Russia to work as a tutor to a rich family. His Swiss-born mother was a tutor as well and Hess had the benefit of learning German and French at home. In 1817, his family moved to Dorpat, Russian Empire (now Tartu, Estonia), where he went to a private school for two years, and then to Dorpat Gymnasium, which he finished in 1822. In autumn of the same year Hess studied medicine at the University of Dorpat. During that time, the chemistry department was responsible for the Chemistry courses of the Medicine and Pharmacy departments and Professor Gottfried W. Osann was giving the lectures in German (an obvious ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geneva
Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevra ; rm, Genevra is the List of cities in Switzerland, second-most populous city in Switzerland (after Zürich) and the most populous city of Romandy, the French-speaking part of Switzerland. Situated in the south west of the country, where the Rhône exits Lake Geneva, it is the capital of the Canton of Geneva, Republic and Canton of Geneva. The city of Geneva () had a population 201,818 in 2019 (Jan. estimate) within its small municipal territory of , but the Canton of Geneva (the city and its closest Swiss suburbs and exurbs) had a population of 499,480 (Jan. 2019 estimate) over , and together with the suburbs and exurbs located in the canton of Vaud and in the French Departments of France, departments of Ain and Haute-Savoie the cross-border Geneva metropolitan area as officially defined by Eurostat, which extends over ,As of 2020, the Eurostat-defined Functional Urban Area of Geneva was made up of 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moritz Von Engelhardt
Otto Moritz (I) Ludwig von Engelhardt ( - ) was a Baltic German mineralogist. He was a member of the Engelhardt family. Biography He was born in 1778 in his family'manor Wiesoan estate in Viisu, Viisu, Estonia. He studied Physics and Chemistry at the Leipzig University, University of Leipzig (1796-1797) and at University of Göttingen (1797-1798). In company with Karl Georg von Raumer, Karl von Raumer he traveled through central Europe and England, and in 1811 he undertook a journey with Friedrich Parrot through the Crimean Peninsula, Crimea and the Caucasus. The results of his extensive tour through Finland in 1818 were published in the work entitled ''Geognostischer Umriss von Finland'' (“Geological sketch of Finland”), vol. i. of an elaborately projected ''Darstellung aus dem Felsgebäude Russlands'' (“Representative rock constructions in Russia,” 1821). From 1820 to 1841 he was professor of mineralogy at University of Dorpat, Dorpat, and in 1826 he entered upon those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exchange Reactions
Exchange may refer to: Physics *Gas exchange is the movement of oxygen and carbon dioxide molecules from a region of higher concentration to a region of lower concentration. Places United States * Exchange, Indiana, an unincorporated community * Exchange, Missouri, an unincorporated community * Exchange, Pennsylvania, an unincorporated community * Exchange, West Virginia, an unincorporated community Elsewhere * Exchange Alley, in London, United Kingdom * Exchange District, a historic area in Winnipeg, Manitoba, Canada Business and economy *''Bureau de change'', a business whose customers exchange one currency for another *Cryptocurrency exchange, a business that allows customers to trade cryptocurrencies or digital currencies. *Digital currency exchangers (a.k.a. DCEs or Bitcoin exchanges), businesses that allow customers to trade digital currencies for other assets, such as conventional fiat money, or different digital currencies *Exchange (economics) *Exchange (organized mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julius Von Mayer
Julius Robert von Mayer (25 November 1814 – 20 March 1878) was a German physician, chemist, and physicist and one of the founders of thermodynamics. He is best known for enunciating in 1841 one of the original statements of the conservation of energy or what is now known as one of the first versions of the first law of thermodynamics, namely that "energy can be neither created nor destroyed". In 1842, Mayer described the vital chemical process now referred to as oxidation as the primary source of energy for any living creature. His achievements were overlooked and priority for the discovery of the ''mechanical equivalent of heat'' was attributed to James Joule in the following year. He also proposed that plants convert light into chemical energy. Early life Mayer was born on 25 November 1814 in Heilbronn, Württemberg (Baden-Württemberg, modern day Germany), the son of a pharmacist. He grew up in Heilbronn. After completing his ''Abitur'', he studied medicine at the Univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conservation Of Energy
In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be ''conserved'' over time. This law, first proposed and tested by Émilie du Châtelet, means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another. For instance, chemical energy is converted to kinetic energy when a stick of dynamite explodes. If one adds up all forms of energy that were released in the explosion, such as the kinetic energy and potential energy of the pieces, as well as heat and sound, one will get the exact decrease of chemical energy in the combustion of the dynamite. Classically, conservation of energy was distinct from conservation of mass. However, special relativity shows that mass is related to energy and vice versa by ''E = mc2'', and science now takes the view that mass-energy as a whole is conserved. Theoretically, this implies that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Intermediate
In chemistry, a reaction intermediate or an intermediate is a molecular entity that is formed from the reactants (or preceding intermediates) but is consumed in further reactions in stepwise chemical reactions that contain multiple elementary steps. Intermediates are the reaction product of one elementary step, but do not appear in the chemical equation for an overall chemical equation. For example, consider this hypothetical stepwise reaction: :A + B -> C + D The reaction includes two elementary steps: :A + B -> X :X -> C + D In this example, X is a reaction intermediate. IUPAC definition The IUPAC Gold Book defines an ''intermediate'' as a compound that has a lifetime greater than a molecular vibration that is formed (directly or indirectly) from the reactants and reacts further to give (either directly or indirectly) the products of a chemical reaction. The lifetime condition distinguishes true, chemically distinct intermediates from vibrational states or such transition st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( 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 viscous liquid that is miscible with water. Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. 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 released; thus the reverse procedure of adding water to the acid should not be performed since the heat released may boi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrate
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understood. Chemical nature Inorganic chemistry Hydrates are inorganic salts "containing water molecules combined in a definite ratio as an integral part of the crystal" that are either bound to a metal center or that have crystallized with the metal complex. Such hydrates are also said to contain ''water of crystallization'' or ''water of hydration''. If the water is heavy water in which the constituent hydrogen is the isotope deuterium, then the term ''deuterate'' may be used in place of ''hydrate''. A colorful example is cobalt(II) chloride, which turns from blue to red upon hydration, and can therefore be used as a water indicator. The notation "''hydrated compound''⋅''n''", where ''n'' is the number of water molecules per formula un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Affinity
In chemical physics and physical chemistry, chemical affinity is the electronic property by which dissimilar chemical species are capable of forming chemical compounds. Chemical affinity can also refer to the tendency of an atom or compound to combine by chemical reaction with atoms or compounds of unlike composition. History Early theories The idea of ''affinity'' is extremely old. Many attempts have been made at identifying its origins. The majority of such attempts, however, except in a general manner, end in futility since "affinities" lie at the basis of all magic, thereby pre-dating science. Physical chemistry, however, was one of the first branches of science to study and formulate a "theory of affinity". The name ''affinitas'' was first used in the sense of chemical relation by German philosopher Albertus Magnus near the year 1250. Later, those as Robert Boyle, John Mayow, Johann Glauber, Isaac Newton, and Georg Stahl put forward ideas on elective affinity in attempts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Law Of Thermodynamics
The first law of thermodynamics is a formulation of the law of conservation of energy, adapted for thermodynamic processes. It distinguishes in principle two forms of energy transfer, heat and thermodynamic work for a system of a constant amount of matter. The law also defines the internal energy of a system, an extensive property for taking account of the balance of energies in the system. The law of conservation of energy states that the total energy of any isolated system, which cannot exchange energy or matter, is constant. Energy can be transformed from one form to another, but can be neither created nor destroyed. The first law for a thermodynamic process is often formulated asThe sign convention (Q is heat supplied ''to'' the system but W is work done ''by'' the system) is that of Rudolf Clausius (Equation IIa on page 384 of Clausius, R. (1850)), and it is followed below. :\Delta U = Q - W, where \Delta U denotes the change in the internal energy of a closed system (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irkutsk
Irkutsk ( ; rus, Иркутск, p=ɪrˈkutsk; Buryat language, Buryat and mn, Эрхүү, ''Erhüü'', ) is the largest city and administrative center of Irkutsk Oblast, Russia. With a population of 617,473 as of the 2010 Census, Irkutsk is the List of cities and towns in Russia by population, 25th-largest city in Russia by population, the fifth-largest in the Siberian Federal District, and one of the largest types of inhabited localities in Russia, cities in Siberia. Located in the south of the eponymous oblast, the city proper lies on the Angara River, a tributary of the Yenisei River, Yenisei, about 850 kilometres (530 mi) to the south-east of Krasnoyarsk and about 520 kilometres (320 mi) north of Ulaanbaatar. The Trans-Siberian Highway (Federal M53 and M55 Highways) and Trans-Siberian Railway connect Irkutsk to other regions in Russia and Mongolia. Many distinguished Russians were sent into exile in Irkutsk for their part in the Decembrist revolt of 1825, and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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