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Niels Bjerrum
Niels Janniksen Bjerrum (11 March 1879 – 30 September 1958) was a Danish chemist. Niels Bjerrum was the son of ophthalmologist Jannik Petersen Bjerrum, and started to study at the University of Copenhagen in 1897. He received his Master's degree in 1902 and his Doctor's degree in 1908, and did research in coordination complex chemistry under Sophus Mads Jørgensen. He became a docent in 1912, and in 1914 he became a professor of chemistry at the Royal Agricultural College (''Landbohøjskolen'') in Copenhagen, as successor of Odin Tidemand Christensen. He stayed on this post until his retirement in 1949, and from 1939 to 1946 he was also the Director of the College. Importantly, Bjerrum introduced the concept of three forms of molecular energy, translational, vibrational and rotational which was important in understanding vibrational spectroscopy. He is also noted for the theory behind the Bjerrum length, and the Bjerrum plot. Bjerrum also performed some of the first res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denmark
Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous administrative division, autonomous territories of the Faroe Islands and Greenland in the north Atlantic Ocean.* * * Metropolitan Denmark, also called "continental Denmark" or "Denmark proper", consists of the northern Jutland peninsula and an archipelago of 406 islands. It is the southernmost of the Scandinavian countries, lying southwest of Sweden, south of Norway, and north of Germany, with which it shares a short border. Denmark proper is situated between the North Sea to the west and the Baltic Sea to the east.The island of Bornholm is offset to the east of the rest of the country, in the Baltic Sea. The Kingdom of Denmark, including the Faroe Islands and Greenland, has roughly List of islands of Denmark, 1,400 islands greater than in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bohr Model
In atomic physics, the Bohr model or Rutherford–Bohr model was a model of the atom that incorporated some early quantum concepts. Developed from 1911 to 1918 by Niels Bohr and building on Ernest Rutherford's nuclear Rutherford model, model, it supplanted the plum pudding model of J. J. Thomson only to be replaced by the quantum atomic model in the 1920s. It consists of a small, dense nucleus surrounded by orbiting electrons. It is analogy, analogous to the structure of the Solar System, but with attraction provided by Coulomb's law, electrostatic force rather than gravity, and with the electron energies quantized (assuming only discrete values). In the history of atomic physics, it followed, and ultimately replaced, several earlier models, including Joseph Larmor's Solar System model (1897), Jean Perrin's model (1901), the Cubical atom, cubical model (1902), Hantaro Nagaoka's Saturnian model (1904), the plum pudding model (1904), Arthur Haas's quantum model (1910), the Ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Danish Physical Chemists
Danish may refer to: * Something of, from, or related to the country of Denmark People * A Danish person, also called a "Dane", can be a national or citizen of Denmark (see Demographics of Denmark) * Culture of Denmark * Danish people or Danes, people with a Danish ancestral or ethnic identity * A member of the Danes, a Germanic tribe * Danish (name), a male given name and surname Language * Danish language, a North Germanic language used mostly in Denmark and Northern Germany * Danish tongue or Old Norse, the parent language of all North Germanic languages Food * Danish cuisine * Danish pastry, often simply called a "Danish" See also * Dane (other) * * Gdańsk * List of Danes * Languages of Denmark The Kingdom of Denmark has only one official language, Danish, the national language of the Danish people, but there are several minority languages spoken, namely Faroese, German, and Greenlandic. A large majority (about 86%) of Danes also ... {{disambigu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1958 Deaths
Events January * January 1 – The European Economic Community (EEC) comes into being. * January 3 – The West Indies Federation is formed. * January 4 ** Edmund Hillary's Commonwealth Trans-Antarctic Expedition completes the third overland journey to the South Pole, the first to use powered vehicles. ** Sputnik 1 (launched on October 4, 1957) falls towards Earth from its orbit and burns up. * January 13 – Battle of Edchera: The Moroccan Army of Liberation ambushes a Spanish patrol. * January 27 – A Soviet-American executive agreement on cultural, educational and scientific exchanges, also known as the "Lacy-Zarubin Agreement, Lacy–Zarubin Agreement", is signed in Washington, D.C. February * February 1 – Egypt and Syria unite to form the United Arab Republic. * February 2 – The ''Falcons'' aerobatic team of the Pakistan Air Force led by Wg Cdr Zafar Masud (air commodore), Mitty Masud set a World record loop, world record performing a 16 aircraft diamon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1879 Births
Events January * January 1 ** The Specie Resumption Act takes effect. The United States Note is valued the same as gold, for the first time since the American Civil War. ** Brahms' Violin Concerto is premiered in Leipzig with Joseph Joachim as soloist and the composer conducting. * January 11 – The Anglo-Zulu War begins. * January 22 – Anglo-Zulu War – Battle of Isandlwana: A force of 1,200 British soldiers is wiped out by over 20,000 Zulu warriors. * January 23 – Anglo-Zulu War – Battle of Rorke's Drift: Following the previous day's defeat, a smaller British force of 140 successfully repels an attack by 4,000 Zulus. February * February 3 – Mosley Street in Newcastle upon Tyne (England) becomes the world's first public highway to be lit by the electric incandescent light bulb invented by Joseph Swan. * February 8 – At a meeting of the Royal Canadian Institute, engineer and inventor Sandford Fleming first proposes the global ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ideal Solution
An ideal solution or ideal mixture is a solution that exhibits thermodynamic properties analogous to those of a mixture of ideal gases. The enthalpy of mixing is zero as is the volume change on mixing. The vapor pressures of all components obey Raoult's law across the entire range of concentrations, and the activity coefficient (which measures deviation from ideality) is equal to one for each component. The concept of an ideal solution is fundamental to both thermodynamics and chemical thermodynamics and their applications, such as the explanation of colligative properties. Physical origin Ideality of solutions is analogous to ideality for gases, with the important difference that intermolecular interactions in liquids are strong and cannot simply be neglected as they can for ideal gases. Instead we assume that the mean strength of the interactions are the same between all the molecules of the solution. More formally, for a mix of molecules of A and B, then the interacti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmotic Coefficient
An osmotic coefficient \phi is a quantity which characterises the deviation of a solvent from ideal behaviour, referenced to Raoult's law. It can be also applied to solutes. Its definition depends on the ways of expressing chemical composition A chemical composition specifies the identity, arrangement, and ratio of the chemical elements making up a compound by way of chemical and atomic bonds. Chemical formulas can be used to describe the relative amounts of elements present in a com ... of mixtures. The osmotic coefficient based on molality ''m'' is defined by: \phi = \frac and on a mole fraction basis by: \phi = -\frac where \mu_A^* is the chemical potential of the pure solvent and \mu_A is the chemical potential of the solvent in a solution, ''M''A is its molar mass, ''x''A its mole fraction, ''R'' the gas constant and ''T'' the temperature in Kelvin. The latter osmotic coefficient is sometimes called the rational osmotic coefficient. The values for the two definitions a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transactions Of The Faraday Society
The ''Journal of the Chemical Society, Faraday Transactions'' was a peer-reviewed scientific journal published from 1905 until 1998. The journal was originally published by the Faraday Society under the name ''Transactions of the Faraday Society'' and was renamed in 1972. History The journal began its publication in 1905 as ''Transactions of the Faraday Society''. When the society merged with the other chemistry societies of the United Kingdom to form the Royal Society of Chemistry, the publication of the journal was transferred to the Chemical Society in 1972 as part of the merger negotiations. The journal was renamed ''Journal of the Chemical Society, Faraday Transactions'', and split in two (''Faraday Transactions I: Physical Chemistry in Condensed Phases'' and ''Faraday Transactions II: Molecular and Chemical Physics''). After the merger, the Royal Society carried the publication until its end. In 1990, the two journals merged into a single ''Journal of the Chemical Society, Far ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Association
In chemistry, ion association is a chemical reaction whereby ions of opposite electric charge come together in solution to form a distinct chemical entity. Ion associates are classified, according to the number of ions that associate with each other, as ''ion pairs'', ''ion triplets'', etc. ''Intimate ion pairs'' are also classified according to the nature of the interaction as contact, solvent-shared or solvent-separated. The most important factor to determine the extent of ion association is the dielectric constant of the solvent. Ion associates have been characterized by means of vibrational spectroscopy, as introduced by Niels Bjerrum, and dielectric-loss spectroscopy. Classification of ion pairs ''Ion pairs'' are formed when a cation and anion, which are present in a solution of an ionizable substance, come together to form a discrete chemical species. There are three distinct types of ''ion pairs'', depending on the extent of solvation of the two ions. For example, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bohr Model
In atomic physics, the Bohr model or Rutherford–Bohr model was a model of the atom that incorporated some early quantum concepts. Developed from 1911 to 1918 by Niels Bohr and building on Ernest Rutherford's nuclear Rutherford model, model, it supplanted the plum pudding model of J. J. Thomson only to be replaced by the quantum atomic model in the 1920s. It consists of a small, dense nucleus surrounded by orbiting electrons. It is analogy, analogous to the structure of the Solar System, but with attraction provided by Coulomb's law, electrostatic force rather than gravity, and with the electron energies quantized (assuming only discrete values). In the history of atomic physics, it followed, and ultimately replaced, several earlier models, including Joseph Larmor's Solar System model (1897), Jean Perrin's model (1901), the Cubical atom, cubical model (1902), Hantaro Nagaoka's Saturnian model (1904), the plum pudding model (1904), Arthur Haas's quantum model (1910), the Ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niels Bohr
Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research. Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of Complementarity (physics), complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a Wave–particle duality, wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philoso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walther Nernst
Walther Hermann Nernst (; 25 June 1864 – 18 November 1941) was a German physical chemist known for his work in thermodynamics, physical chemistry, electrochemistry, and solid-state physics. His formulation of the Nernst heat theorem helped pave the way for the third law of thermodynamics, for which he won the 1920 Nobel Prize in Chemistry. He is also known for developing the Nernst equation in 1887. He studied physics and mathematics at the universities of Zürich, Berlin, Graz and Würzburg, where he received his doctorate 1887. In 1889, he finished his habilitation at University of Leipzig. Life and career Early years Nernst was born in Briesen, Germany (now Wąbrzeźno, Poland) to Gustav Nernst (1827–1888) and Ottilie Nerger (1833–1876). His father was a country judge. Nernst had three older sisters and one younger brother. His third sister died of cholera. Nernst went to elementary school at Graudenz, Germany (now Grudziądz, Poland). Studies Nernst started ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
