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Graham's Law
Graham's law of effusion (also called Graham's law of diffusion) was formulated by Scottish physical chemist Thomas Graham in 1848. Keith J. Laidler and John M. Meiser, ''Physical Chemistry'' (Benjamin/Cummings 1982), pp. 18–19 Graham found experimentally that the rate of effusion of a gas is inversely proportional to the square root of the molar mass of its particles. This formula is stated as: :=\sqrt, where: :Rate1 is the rate of effusion for the first gas. (volume or number of moles per unit time). :Rate2 is the rate of effusion for the second gas. :''M1'' is the molar mass of gas 1 :''M2'' is the molar mass of gas 2. Graham's law states that the rate of diffusion or of effusion of a gas is inversely proportional to the square root of its molecular weight. Thus, if the molecular weight of one gas is four times that of another, it would diffuse through a porous plug or escape through a small pinhole in a vessel at half the rate of the other (heavier gases diffuse mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Graham
Thomas Graham may refer to: Politicians and diplomats *Thomas Graham, 1st Baron Lynedoch (1748–1843), British politician and soldier * Thomas Graham Jr. (diplomat) (born 1933), nuclear expert and senior U.S. diplomat *Sir Thomas Graham (barrister) (1860–1940), South African lawyer and politician *Ted Graham, Baron Graham of Edmonton (Thomas Edward Graham, 1925–2020), British Labour Co-operative politician * Tommy Graham (Scottish politician) (1943–2015), Scottish Member of Parliament for Renfrew West and Inverclyde * Thomas Graham (Canadian politician) (1914–1988), Canadian Member of Provincial Parliament for York Centre * Thomas Jefferson Graham (1832–1902), American politician in Wisconsin and Montana Scientists and medics *Thomas Graham (chemist) (1805–1869), Scottish chemist * Thomas Graham (apothecary) (1666–1733), apothecary to King George I and George II * Thomas J. Graham (born 1962), American orthopaedic surgeon Sportspeople * Thomas Graham (footballer, bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manhattan Project
The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the project was directed by Major General Leslie Groves of the United States Army Corps of Engineers, U.S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the bombs. The Army program was designated the Manhattan District, as its first headquarters were in Manhattan; the name gradually superseded the official codename, Development of Substitute Materials, for the entire project. The project absorbed its earlier British counterpart, Tube Alloys, and subsumed the program from the American civilian Office of Scientific Research and Development. The Manhattan Project employed nearly 130,000 people at its peak and cost nearly US$2 billion (equivalent to about $ b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin
The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possible temperature (absolute zero), taken to be 0 K. By definition, the Celsius scale (symbol °C) and the Kelvin scale have the exact same magnitude; that is, a rise of 1 K is equal to a rise of 1 °C and vice versa, and any temperature in degrees Celsius can be converted to kelvin by adding 273.15. The 19th century British scientist Lord Kelvin first developed and proposed the scale. It was often called the "absolute Celsius" scale in the early 20th century. The kelvin was formally added to the International System of Units in 1954, defining 273.16 K to be the triple point of water. The Celsius, Fahrenheit, and Rankine scales were redefined in terms of the Kelvin scale using this definition. The 2019 revision of the SI now defines the kelvin in terms of energy by setting the Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish physicist and mathematician who was responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and light as different manifestations of the same phenomenon. Maxwell's equations for electromagnetism achieved the Unification (physics)#Unification of magnetism, electricity, light and related radiation, second great unification in physics, where Unification (physics)#Unification of gravity and astronomy, the first one had been realised by Isaac Newton. Maxwell was also key in the creation of statistical mechanics. With the publication of "A Dynamical Theory of the Electromagnetic Field" in 1865, Maxwell demonstrated that electric force, electric and magnetic fields travel through space as waves moving at the speed of light. He proposed that light is an undulation in the same medium that is the cause of electric and magnetic phenomena. (Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amedeo Avogadro
Lorenzo Romano Amedeo Carlo Avogadro, Count of Quaregna and Cerreto (, also , ; 9 August 17769 July 1856) was an Italian scientist, most noted for his contribution to molecular theory now known as Avogadro's law, which states that equal volumes of gases under the same conditions of temperature and pressure will contain equal numbers of molecules. In tribute to him, the ratio of the number of elementary entities (atoms, molecules, ions or other particles) in a substance to its amount of substance (the latter having the unit mole), , is known as the Avogadro constant. This constant is denoted ''N''A, and is one of the seven defining constants of the SI. Biography Amedeo Avogadro was born in Turin to a noble family of the Kingdom of Sardinia (now part of Italy) in the year 1776. He graduated in ecclesiastical law at the late age of 20 and began to practice. Soon after, he dedicated himself to physics and mathematics (then called ''positive philosophy''), and in 1809 starte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodynamica
''Hydrodynamica, sive de Viribus et Motibus Fluidorum Commentarii'' (Latin for ''Hydrodynamics, or commentaries on the forces and motions of fluids'') is a book published by Daniel Bernoulli in 1738. The title of this book eventually christened the field of fluid mechanics as hydrodynamics. This book introduced the Bernoulli's principle, stating the first form of conservation of energy in fluid dynamics. Description The book deals with fluid mechanics and is organized around preliminary versions of the conservation of energy, as received from Christiaan Huygens's formulation of Vis viva, ''vis viva'' (Latin for living forces). The book describes the theory of water flowing through a tube and of water flowing from a hole in a container. In doing so, Bernoulli explained the nature of hydrodynamic pressure and discovered the role of loss of ''vis viva'' in fluid flow, which would later be known as the Bernoulli principle. The book also discusses hydraulic machines and introduces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniel Bernoulli
Daniel Bernoulli ( ; ; – 27 March 1782) was a Swiss people, Swiss-France, French mathematician and physicist and was one of the many prominent mathematicians in the Bernoulli family from Basel. He is particularly remembered for his applications of mathematics to mechanics, especially fluid mechanics, and for his pioneering work in probability and statistics. His name is commemorated in the Bernoulli's principle, a particular example of the conservation of energy, which describes the mathematics of the mechanism underlying the operation of two important technologies of the 20th century: the carburetor and the aeroplane wing. Early life Daniel Bernoulli was born in Groningen (city), Groningen, in the Netherlands, into a Bernoulli family, family of distinguished mathematicians.Murray Rothbard, Rothbard, MurrayDaniel Bernoulli and the Founding of Mathematical Economics, ''Mises Institute'' (excerpted from ''An Austrian Perspective on the History of Economic Thought'') The Bernou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colloid
A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend the definition to include substances like aerosols and gels. The term colloidal suspension refers unambiguously to the overall mixture (although a narrower sense of the word '' suspension'' is distinguished from colloids by larger particle size). A colloid has a dispersed phase (the suspended particles) and a continuous phase (the medium of suspension). The dispersed phase particles have a diameter of approximately 1 nanometre to 1 micrometre. Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color. Colloidal suspensions are the subject of interface and colloid science. This field of study began in 1845 by Franc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suspension (chemistry)
In chemistry, a suspension is a heterogeneous mixture of a fluid that contains solid particles sufficiently large for sedimentation. The particles may be visible to the naked eye, usually must be larger than one micrometer, and will eventually settle, although the mixture is only classified as a suspension when and while the particles have not settled out. Properties A suspension is a heterogeneous mixture in which the solid particles do not dissolve, but get suspended throughout the bulk of the solvent, left floating around freely in the medium. The internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation, with the use of certain excipients or suspending agents. An example of a suspension would be sand in water. The suspended particles are visible under a microscope and will settle over time if left undisturbed. This distinguishes a suspension from a colloid, in which the colloid particles are smaller and do not settle. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Döbereiner
Johann, typically a male given name, is the German form of ''Iohannes'', which is the Latin form of the Greek name ''Iōánnēs'' (), itself derived from Hebrew name '' Yochanan'' () in turn from its extended form (), meaning "Yahweh is Gracious" or "Yahweh is Merciful". Its English language equivalent is John. It is uncommon as a surname. People People with the name Johann include: Mononym * Johann, Count of Cleves (died 1368), nobleman of the Holy Roman Empire * Johann, Count of Leiningen-Dagsburg-Falkenburg (1662–1698), German nobleman *Johann, Prince of Hohenzollern-Sigmaringen (1578–1638), German nobleman A–K * Johann Adam Hiller (1728–1804), German composer * Johann Adam Reincken (1643–1722), Dutch/German organist * Johann Adam Remele (died 1740), German court painter * Johann Adolf I, Duke of Saxe-Weissenfels (1649–1697) * Johann Adolph Hasse (1699-1783), German Composer * Johann Altfuldisch (1911—1947), German Nazi SS concentration camp officer executed f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total population of over 84 million in an area of , making it the most populous member state of the European Union. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The Capital of Germany, nation's capital and List of cities in Germany by population, most populous city is Berlin and its main financial centre is Frankfurt; the largest urban area is the Ruhr. Settlement in the territory of modern Germany began in the Lower Paleolithic, with various tribes inhabiting it from the Neolithic onward, chiefly the Celts. Various Germanic peoples, Germanic tribes have inhabited the northern parts of modern Germany since classical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium Hexafluoride
Uranium hexafluoride, sometimes called hex, is the inorganic compound with the formula . Uranium hexafluoride is a volatile, white solid that is used in enriching uranium for nuclear reactors and nuclear weapons. Preparation Uranium dioxide is converted with hydrofluoric acid (HF) to uranium tetrafluoride: : The resulting is subsequently oxidized with fluorine to give the hexafluoride: : In samples contaminated with uranium trioxide, uranyl fluoride, an oxyfluoride compound is produced in the HF step: : which can be fluorinated to produce the same product, uranium hexafluoride. : The fluorination step in both reactions above are highly exothermic. Properties Physical properties At atmospheric pressure, sublimes at 56.5 °C. The solid-state structure was determined by neutron diffraction at 77 K and 293 K.J. C. Taylor, P. W. Wilson, J. W. Kelly: „The structures of fluorides. I. Deviations from ideal symmetry in the structure of crystalline UF6: a neutron diffract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
