Loschmidt, Joseph


Loschmidt, Joseph

▪ Austrian chemist
in full  Johann Joseph Loschmidt  
born May 15, 1821, Putschin, Bohemia, Austrian Empire [now in Czech Republic]
died July 8, 1895, Vienna, Austria

      German chemist who made advances in the study of aromatic hydrocarbons.

      The son of poor peasants, Loschmidt gained an education through the help of his village priest, and by 1839 he was a student at the German University in Prague. Moving to Vienna in 1841, he completed his university studies in 1843 but was unable to obtain a teaching post. His attempts to succeed in business ended in bankruptcy in 1854, and he decided to return to his studies in the natural sciences. In 1856 Loschmidt qualified as a teacher and obtained a post at the Vienna Realschule. He turned to research in chemistry and theoretical physics and soon began publishing scientific papers. He was appointed an assistant professor of physical chemistry at the University of Vienna in 1868 and went on to become an important figure in Vienna's scientific community.

      Loschmidt was the first to use double and triple lines to graphically represent the double and triple bonds in organic molecules. He recognized that most “aromatic compounds” (i.e., aromatic (aromatic compound) hydrocarbons, so called because they were obtained from pleasantly fragrant substances) could be derived from benzene by replacing one or more hydrogen substituents by other atoms or groups. The term “aromatic” thus came to be applied to any hydrocarbon that has the benzene ring as part of its structure, regardless of the question of aroma. Loschmidt was the first to state that in alcohols containing several OH groups, each OH group is attached to a different carbon atom. He partly explained the structures of several organic and inorganic compounds, among them benzene, toluene, and ozone, and he also recognized that an element could have several valences. Loschmidt made perhaps the first accurate calculations of the size of air molecules and of the number of molecules in a gram-mole (the quantity now commonly called the Avogadro constant (Avogadro's number)). He arrived at a size of somewhat less than 10−7 cm for the diameter of the molecules in air, which is relatively close to the accepted figure of 0.5 × 10−7 cm.

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Universalium. 2010.

Look at other dictionaries:

  • Loschmidt — Joseph (Johann), Czech chemist and physicist, 1821–1895. See L. number …   Medical dictionary

  • Joseph Loschmidt — Josef Loschmidt (Johann) Josef (oder Joseph) Loschmidt (* 15. März 1821 in Putschirn (heute Počerny, Tschechien) bei Karlsbad; † 8. Juli 1895 in Wien) war ein österreichischer Physiker und Chemiker. Er gehörte zu jenen g …   Deutsch Wikipedia

  • Loschmidt — Josef Loschmidt (Johann) Josef (oder Joseph) Loschmidt (* 15. März 1821 in Putschirn (heute Počerny, Tschechien) bei Karlsbad; † 8. Juli 1895 in Wien) war ein österreichischer Physiker und Chemiker. Er gehörte zu jenen g …   Deutsch Wikipedia

  • Loschmidt'sche Zahl — Josef Loschmidt Die Loschmidt Konstante NL ist eine nach Josef Loschmidt benannte physikalische Konstante, die die Anzahl der Moleküle pro Volumeneinheit eines idealen Gases unter Normalbedingungen angibt. Ihr derzeit allgemein empfohlener Wert… …   Deutsch Wikipedia

  • Loschmidt-Zahl — Josef Loschmidt Die Loschmidt Konstante NL ist eine nach Josef Loschmidt benannte physikalische Konstante, die die Anzahl der Moleküle pro Volumeneinheit eines idealen Gases unter Normalbedingungen angibt. Ihr derzeit allgemein empfohlener Wert… …   Deutsch Wikipedia

  • Loschmidt-Konstante — Josef Loschmidt Die Loschmidt Konstante NL ist eine nach Josef Loschmidt benannte physikalische Konstante, die die Anzahl der Moleküle pro Volumeneinheit eines idealen Gases unter Normalbedingungen angibt. Ihr Wert beträgt nach derzeitiger… …   Deutsch Wikipedia

  • Loschmidt's constant — /ˈlɒʃmɪts ˌkɒnstənt/ (say loshmits .konstuhnt) noun the number of molecules per unit volume of an ideal gas at standard temperature and pressure. Also, Loschmidt s number. {named after Joseph Loschmidt, 1821–95, German physicist} …   Australian English dictionary

  • Loschmidt's number — /loh shmits/, Chem. the number of molecules in one cubic centimeter of an ideal gas at standard temperature and pressure, equal to 2.687 × 1019. Cf. Avogadro s number. [after Joseph Loschmidt (1821 95), Austrian chemist, who calculated it] * * * …   Universalium

  • Loschmidt — Lọschmidt,   Joseph, österreichischer Chemiker und Physiker, * Putschirn (bei Karlsbad) 15. 3. 1821, ✝ Wien 8. 7. 1895; ab 1856 Lehrer in Wien und von 1872 91 Professor für physikalische Chemie an der dortigen Universität; arbeitete u. a. über… …   Universal-Lexikon

  • loschmidt number — ˈlōˌshmit noun Usage: usually capitalized L Etymology: after Joseph Loschmidt died 1895 Austrian physicist : the number of molecules per unit volume of an ideal gas at 0° C and a pressure of 1 atmosphere, its value for 1 cubic centimeter being… …   Useful english dictionary


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