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Friedrich Wilhelm Ostwald
Friedrich Wilhelm Ostwald (; 4 April 1932) was a Baltic German chemist and philosopher. Ostwald is credited with being one of the founders of the field of physical chemistry, with Jacobus Henricus van 't Hoff, Walther Nernst, and Svante Arrhenius. He received the Nobel Prize in Chemistry in 1909 for his scientific contributions to the fields of catalysis, chemical equilibria and reaction velocities. Following his 1906 retirement from academic life, Ostwald became much involved in philosophy, art, and politics. He made significant contributions to each of these fields. He has been described as a polymath. Early life and education Ostwald was born ethnically Baltic German in Riga, Russian Empire (now Latvia) to master-cooper Gottfried Wilhelm Ostwald (1824–1903) and Elisabeth Leuckel (1824–1903). He was the middle child of three, born after Eugen (1851–1932) and before Gottfried (1855–1918). Ostwald developed an interest in science as a child and conducted experiments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riga
Riga (; lv, Rīga , liv, Rīgõ) is the capital and largest city of Latvia and is home to 605,802 inhabitants which is a third of Latvia's population. The city lies on the Gulf of Riga at the mouth of the Daugava river where it meets the Baltic Sea. Riga's territory covers and lies above sea level, on a flat and sandy plain. Riga was founded in 1201 and is a former Hanseatic League member. Riga's historical centre is a UNESCO World Heritage Site, noted for its Art Nouveau/Jugendstil architecture and 19th century wooden architecture. Riga was the European Capital of Culture in 2014, along with Umeå in Sweden. Riga hosted the 2006 NATO Summit, the Eurovision Song Contest 2003, the 2006 IIHF Men's World Ice Hockey Championships, 2013 World Women's Curling Championship and the 2021 IIHF World Championship. It is home to the European Union's office of European Regulators for Electronic Communications (BEREC). In 2017, it was named the European Region of Gastronomy. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Livingston Rutgers Morgan
John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second Epistle of John, often shortened to 2 John * Third Epistle of John, often shortened to 3 John People * John the Baptist (died c. AD 30), regarded as a prophet and the forerunner of Jesus Christ * John the Apostle (lived c. AD 30), one of the twelve apostles of Jesus * John the Evangelist, assigned author of the Fourth Gospel, once identified with the Apostle * John of Patmos, also known as John the Divine or John the Revelator, the author of the Book of Revelation, once identified with the Apostle * John the Presbyter, a figure either identified with or distinguished from the Apostle, the Evangelist and John of Patmos Other people with the given name Religious figures * John, father of Andrew the Apostle and Saint Peter * Pope John ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pipette
A pipette (sometimes spelled as pipett) is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid, often as a media dispenser. Pipettes come in several designs for various purposes with differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. Many pipette types work by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. Measurement accuracy varies greatly depending on the instrument. History The first simple pipettes were made in glass, such as Pasteur pipettes. Large pipettes continue to be made in glass; others are made in squeezable plastic for situations where an exact volume is not required. The first micropipette was patented in 1957 by Dr Heinrich Schnitger (Marburg, Germany). The founder of the company Eppendorf, Dr. Heinrich Netheler, inherited the rights and started the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscometer
A viscometer (also called viscosimeter) is an instrument used to measure the viscosity of a fluid. For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Thus, a rheometer can be considered as a special type of viscometer. Viscometers only measure under one flow condition. In general, either the fluid remains stationary and an object moves through it, or the object is stationary and the fluid moves past it. The drag caused by relative motion of the fluid and a surface is a measure of the viscosity. The flow conditions must have a sufficiently small value of Reynolds number for there to be laminar flow. At 20°C, the dynamic viscosity (kinematic viscosity × density) of water is 1.0038 mPa·s and its kinematic viscosity (product of flow time × factor) is 1.0022mm2/s. These values are used for calibrating certain types of viscometers. Standard laboratory viscometers for liquids U-tube viscometers These devices are also known as gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostwald's Rule
In materials science, Ostwald's rule or Ostwald's step rule, conceived by Wilhelm Ostwald, describes the formation of polymorphs. The rule states that usually the less stable polymorph crystallizes first. Unstable polymorphs more closely resemble the state in solution, and thus are kinetically advantaged. From hot water, metastable, fibrous crystals of benzamide appear first, later to spontaneously convert to the more stable rhombic polymorph. Another example is magnesium carbonate, which more readily forms dolomite. A dramatic example is phosphorus, which upon sublimation first forms the less stable white phosphorus, which only slowly polymerizes to the red allotrope. This is notably the case for the anatase polymorph of titanium dioxide, which having a lower surface energy In surface science, surface free energy (also interfacial free energy or surface energy) quantifies the disruption of intermolecular bonds that occurs when a surface is created. In solid-state physics, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostwald Ripening
Ostwald ripening is a phenomenon observed in solid solutions or liquid sols that describes the change of an inhomogeneous structure over time, i.e., small crystals or sol particles dissolve, and redeposit onto larger crystals or sol particles. Dissolution of small crystals or sol particles and the redeposition of the dissolved species on the surfaces of larger crystals or sol particles was first described by Wilhelm Ostwald in 1896. For colloidal systems, Ostwald ripening is also found in water-in-oil emulsions, while flocculation is found in oil-in-water emulsions. Mechanism This thermodynamically-driven spontaneous process occurs because larger particles are more energetically favored than smaller particles. This stems from the fact that molecules on the surface of a particle are energetically less stable than the ones in the interior. Consider a cubic crystal of atoms: all the atoms inside are bonded to 6 neighbours and are quite stable, but atoms on the surface are onl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostwald Process
The Ostwald process is a chemical process used for making nitric acid (HNO3). Wilhelm Ostwald developed the process, and he patented it in 1902. The Ostwald process is a mainstay of the modern chemical industry, and it provides the main raw material for the most common type of fertilizer production. Historically and practically, the Ostwald process is closely associated with the Haber process, which provides the requisite raw material, ammonia (NH3). Description Stage 1 Ammonia is converted to nitric acid in 2 stages. It is oxidized by heating with oxygen in the presence of a catalyst such as platinum with 10% rhodium, platinum metal on fused silica wool, copper or nickel, to form nitric oxide (nitrogen(II) oxide) and water (as steam). This reaction is strongly exothermic, making it a useful heat source once initiated: :4 NH3 (g) + 5 O2 (g) -> 4 NO (g) + 6 H2O (g) (Δ''H'' = −905.2 kJ/mol) Stage 2 Stage two encompasses two reactions and is carried out in an absorption a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostwald Dilution Law
Wilhelm Ostwald’s dilution law is a relationship proposed in 1888 between the dissociation constant ' and the degree of dissociation ' of a weak electrolyte. The law takes the form :K_d = \cfrac = \frac \cdot c_0 Where the square brackets denote concentration, and is the total concentration of electrolyte. Using \alpha=\Lambda_c/\Lambda_0, where \Lambda_c is the molar conductivity at concentration c and \Lambda_0 is the limiting value of molar conductivity extrapolated to zero concentration or infinite dilution, this results in the following relation: :K_d = \cfrac \cdot c_0 Derivation Consider a binary electrolyte AB which dissociates reversibly into A+ and B− ions. Ostwald noted that the law of mass action can be applied to such systems as dissociating electrolytes. The equilibrium state is represented by the equation: :AB + B^- If ' is the fraction of dissociated electrolyte, then ' is the concentration of each ionic species. must, therefore be the fraction of ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostwald Color System
In colorimetry, the Ostwald color system is a color space that was invented by the Baltic German chemist Wilhelm Ostwald. Associated wit''The Color Harmony Manual'' it comprises a set of paint chips representing the Ostwald color space. There are four different editions of the ''Color Harmony Manual''. Each manual is made up of charts, with each chart being a different color space. Ostwald Ostwald recommended a systematic arrangement of colors and a standardization of colors used. Ostwald believed colors should only be used and selected from a finite collection. He acknowledged that his system left out some intermediate colors between the ones he selected, but he did not work to include them in his color space. Ostwald's system provides a single, midpoint interpolation between adjacent colors. It does not have an easy way of recording millions of colors. The charts The ''Color Harmony Manual'' is made up of charts of colored chips representing a color space. The overall s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood–gas Partition Coefficient
Blood–gas partition coefficient, also known as Ostwald coefficient for blood–gas, is a term used in pharmacology to describe the solubility of inhaled general anesthetics in blood. According to Henry's law, the ratio of the concentration in blood to the concentration in gas that is in contact with that blood, when the partial pressure in both compartments is equal, is nearly constant at sufficiently low concentrations. The partition coefficient is defined as this ratio and, therefore, has no units. The concentration of the anesthetic in blood includes the portion that is undissolved in plasma and the portion that is dissolved (bound to plasma proteins). The more soluble the inhaled anesthetic is in blood compared to in air, the more it binds to plasma proteins in the blood and the higher the blood–gas partition coefficient. It is inversely related to induction rate. Induction rate is defined as the speed at which an agent produces anesthesia. The higher the blood:gas partit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HSL And HSV
HSL (for hue, saturation, lightness) and HSV (for hue, saturation, value; also known as HSB, for hue, saturation, brightness) are alternative representations of the RGB color model, RGB color model, designed in the 1970s by computer graphics researchers to more closely align with the way human vision perceives color-making attributes. In these models, colors of each ''hue'' are arranged in a radial slice, around a central axis of neutral colors which ranges from black at the bottom to white at the top. The HSL representation models the way different paints mix together to create color in the real world, with the ''lightness'' dimension resembling the varying amounts of black or white paint in the mixture (e.g. to create "light red", a red pigment can be mixed with white paint; this white paint corresponds to a high "lightness" value in the HSL representation). Fully saturated colors are placed around a circle at a lightness value of ½, with a lightness value of 0 or 1 correspon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mole (unit)
The mole, symbol mol, is the unit of amount of substance in the International System of Units (SI). The quantity amount of substance is a measure of how many elementary entities of a given substance are in an object or sample. The mole is defined as containing exactly elementary entities. Depending on what the substance is, an elementary entity may be an atom, a molecule, an ion, an ion pair, or a subatomic particle such as an electron. For example, 10 moles of water (a chemical compound) and 10 moles of mercury (a chemical element), contain equal amounts of substance and the mercury contains exactly one atom for each molecule of the water, despite the two having different volumes and different masses. The number of elementary entities in one mole is known as the Avogadro number, which is the approximate number of nucleons (protons or neutrons) in one gram of ordinary matter. The previous definition of a mole was simply the number of elementary entities equal to that of 12 gram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
