Stoichiometry IPAc en icon s t k i m t r i is a branch of chemistry that deals with the relative ... of NH sub 3 sub chem N 2 3 chem H 2 &rarr 2 chem NH 3 Stoichiometry can be used to find quantities such as the amount ... . Stoichiometry calculations can predict how elements and components diluted in a standard solution react in experimental conditions. Stoichiometry is founded on the law of conservation of mass the mass of the reactants equals the mass of the products. Reaction stoichiometry describes the quantitative ..., reaction stoichiometry describes the 1 3 2 ratio of molecules of nitrogen, hydrogen, and ammonia. Composition stoichiometry describes the quantitative mass relationships among elements in compounds. For example, composition stoichiometry describes the nitrogen to hydrogen ratio in the compound ammonia ... have integer ratio stoichiometry in amount of matter units moles, number of particles , some ... numbers. These materials therefore violate the law of definite proportions that forms the basis of stoichiometry along with the law of multiple proportions . Gas stoichiometry deals with reactions ... the mass ratio. Etymology The term stoichiometry is derived from the Greek language Greek words ... counts of the Biblical canon canonical New Testament and some of the Apocrypha . Definition Stoichiometry .... Stoichiometry is often used to balance chemical equations reaction stoichiometry . For example ... H 2 O Reaction stoichiometry describes the 2 1 2 ratio of hydrogen, oxygen, and water molecules in the above equation. The term stoichiometry is also often used for the Mole unit molar proportions of elements in stoichiometric compounds composition stoichiometry . For example, the stoichiometry of hydrogen ... are whole numbers. Stoichiometry is not only used to balance chemical equations but also used in conversions ... mbox g NaCl 1 right left frac 1 mbox mol NaCl 58.44 mbox g NaCl right 0.034 text mol math Stoichiometry .... The reactions may differ in their stoichiometry. For example, the methylation of benzene math mathrm ... more details
Ecological stoichiometry considers how the balance of energy and elements affect and are affected by organisms and their interactions in ecosystems . Ecological stoichiometry has a long history in ecology with early references to the constraints of mass balance made by Liebig, Lotka, and Redfield. This research area in ecology has recently gained momentum by explicitly linking the elemental physiology of organisms to their food web interactions and ecosystem function. Most work in ecological stoichiometry focuses on the interface between a consumer and its food. This interface, whether it is between plants and their resources or large herbivores and grasses, is often characterized by dramatic differences in the elemental composition of each participant. Consider termites which have a body C N of about 5 but consume wood with a C N ratio of 300 1000. Ecological stoichiometry primarily asks 1 why do elemental imbalances arise in nature? 2 how is consumer physiology and life history affected by elemental imbalances? and 3 what are the subsequent effects on ecological processes in ecosystems? Elemental imbalances are defined by a mismatch between the elemental demands of a consumer and that present in its resources. Mismatches often arise between grazers and their food because plants and their derived organic matter vary considerably in their elemental composition while metazoan consumers have less elemental flexibility. For example, carbon to phosphorus ratios in the suspended organic matter in lakes i.e., algae, bacteria, and detritus can vary between 100 and 1000 whereas C P ... stoichiometry seeks to discover how the chemical content of organisms shapes their ecology . Ecological stoichiometry has been applied to studies of nutrient recycling, resource competition, animal ... is one very famous application of stoichiometric principles to ecology. Ecological Stoichiometry ... reflist Ecological stoichiometry note 0 Ecological Stoichiometry The Biology of Elements from ... more details
In chemistry , the Mole Map is a graphical representation of an algorithm that compares molar mass , number of particles mole, and factors from balanced equations or other formulae. Category Stoichiometry chem stub ... more details
Gram atomic mass is the mass , in gram s, of one mole unit mole of atom s in a monatomic chemical element . It is numerically equal to the relative atomic mass or atomic weight in grams. chem stub Category Stoichiometry Category Mass el sr ... more details
4S may refer to 4S Ranch, California , an unincorporated community in San Diego County Scandinavian Simvastatin Survival Study , a multicenter clinical trial that was performed in 1990s in Scandinavia Sensitivity, Speed, Specificity and Stoichiometry, the 4 advantages of mass spectrometry Society for Social Studies of Science , an academic organization Toyota S engine Toshiba 4S , a nuclear reactor iPhone 4S , the 5th generation of the iPhone See also S4 disambiguation Letter NumberCombDisambig it 4S ja 4S ... more details
Orphan date February 2009 Context date October 2009 A Job plot also known as the method of continuous variation or Job s method named after P. Job is used to determine the stoichiometry of a binding event. This method is widely used in analytical chemistry , instrumental analysis , and advanced chemical equilibrium texts and research articles. In solutions where two species are present i.e. species A and species B , one species A may bind to the other species B . In some cases, more than one A will bind with a single B. One way to determine the amount of A binding to B is by using a Job plot. In this method, the total molar concentration of the two binding partners e.g. a protein and ligand or a metal and a ligand are held constant, but their mole fractions are varied. An observable that is proportional to complex formation such as absorption signal or enzymatic activity is plotted against the mole fractions of these two components. The maximum or minimum on the plot corresponds to the stoichiometry of the two species ref Huang, C.Y. Determination of Binding Stoichiometry by the Continuous Variation Method The Job Plot. Methods in Enzymology 1982 87 , 509 525. ref if sufficiently high concentrations are used. This method is named after P. Job, who first introduced this methodology in 1928. ref Job, P. Annali di Chimica Applicata 1928 9 , 113 203 ref There are several conditions that must be met in order for Job s method to be applicable ref name MacCarthy cite journal last MacCarthy first Patrick coauthors Zachary D. Hill date February 1986 title Novel Approach to Job s Method journal Journal of Chemical Education volume 63 issue 3 pages 162 167 ref The system must conform to Beer s law One complex must predominate under the conditions of the experiment The Total concentration of the two binding partners must be maintained constant pH and ionic strength must be maintained constant References reflist Analytical chemistry Category Scientific techniques ... more details
In structural biology , a protomer is the structural unit of an oligomeric protein . A protomer can be a protein subunit or several different subunits, that assemble in a defined stoichiometry to form an oligomer . The protomer is the smallest subset of different subunits that form the oligomer. The protomers usually arrange in cyclic symmetry to form closed point group symmetries . Protomers are the main subunit in a viral capsid . br Examples br Different polypeptide chains protein subunits are conventionally designated by Greek letters. The number of each subunit in the oligomeric complex is indicated by the subscript number, similar to a chemical formula of a compound consisting of elements. Hemoglobin consists of two chains and two chains. The oligomer stoichiometry is thus sub 2 sub sub 2 sub . Hemoglobin is a heterotetramer consisting of four subunits two and two . It is a dimer of two protomers. Aspartate carbamoyltransferase has a sub 6 sub sub 6 sub subunit composition. The six protomers are arranged in D sub 3 sub symmetry. enzyme stub Category Structural biology Category Polymer chemistry es Prot mero fr Protom re ... more details
In chemistry, the phrase conversion has several meanings Image Conversion, Selectivity and Yield.svg thumb 500px specifically the property X related to the yield chemistry yield Y by multiplication with the selectivity S , i.e. the mathematical definition X conversion S selectivity Y yield , all calculated on a molar basis e.g. in a certain reaction, 90 of substance A is converted consumed , but only 80 of it is converted to the desired substance B and 20 to undesired by products, so conversion of A is 90 , selectivity for B 80 and yield of substance B 72 90 80 in a general sense the action of a chemical reaction , e.g. the conversion of molecule A to molecule B note that in this general sense, conversion rate would be synonymous with reaction rate Category Stoichiometry et Konversioon keemia fr Taux de conversion ru ... more details
Ernst Fischer may refer to Ernst Fischer composer 1900 1975 , German composer and keyboard player Ernst Fischer writer 1899 1972 , an Austrian journalist, writer and politician Ernst Otto Fischer 1918 2007 , German chemist, Nobel prizewinner Ernst Gottfried Fischer 1754 1831 , German chemist developer of stoichiometry theory together with Jeremias Richter Ernst Kuno Berthold Fischer 1824 1907 , German philosopher Ernst Sigismund Fischer , 1875 1954 , Austrian mathematician See also Fischer hndis name Fischer, Ernst de Ernst Fischer ru ... more details
for the publisher Karl Baedeker Karl Baedeker ca. 1877 &ndash 1914 was a Germany German scientist . One of his scientific discoveries was that the resistivity of cuprous iodide CuI depended on its stoichiometry . Baedeker was killed in action during World War I . References Electronic Genie The tangled history of silicon by Frederick Seitz and Norman G. Einspruch, University of Illinois Press, Urbana and Chicago, USA, 1998. Persondata Metadata see Wikipedia Persondata . NAME Baedeker, Karl ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH 1877 PLACE OF BIRTH DATE OF DEATH 1914 PLACE OF DEATH DEFAULTSORT Baedeker, Karl Category 1877 births Category 1914 deaths Category German physicists Category German military personnel killed in World War I de Karl Baedeker Physiker ... more details
Orphan date February 2009 The stoichiometric point is a term commonly used to describe a particular fuel air ratio in a combustion engine. The stoichiometric air fuel ratio for petrol gasoline is 14.7 to 1 by weight. Related concepts include Air fuel ratio Air fuel ratio Stoichiometry E85 in standard engines Lean burn Combustion Gasoline direct injection which can use ultra lean modes many times the stoichiometirc ratio Catalytic converter s which are at peak efficient when the engine runs slightly above the stoichiometirc point Category Engine fuel system technology Chemistry stub ... more details
In chemistry , yield , also referred to as and reaction yield , is the amount of substance amount of Product chemistry product obtained in a chemical reaction . ref name vogel Vogel, A.I., Tatchell, AR., Furnis, B.S., Hannaford, A.J. and P.W.G. Smith. Vogel s Textbook of Practical OrganicHall, 19936 3. ref The absolute yield can be given as the weight in gram s or in Mole unit moles molar yield . The fractional yield , relative yield , or percentage yield , which serve to measure the effectiveness of a Chemical synthesis synthetic procedure , is calculated by dividing the amount of the obtained product by the theoretical yield the unit of measure for both must be the same center math mbox fractional yield frac mbox actual yield mbox theoretical yield math center One or more reactants in a chemical reaction are often used in excess. The theoretical yield is therefore calculated based on the molar amount of the limiting reactant , taking into account the stoichiometry of the reaction. For the calculation it is usually assumed that there is only one reaction involved. The ideal or theoretical yield of a chemical reaction would be 100 , a value that is impossible to achieve due to limitations in measurement accuracy. According to Vogel s Textbook of Practical Organic Chemistry, yields around 100 are called quantitative , yields above 90 are called excellent , yields above 80 are very good , yields above 70 are good , yields above 50 are fair , and yields below 40 are called poor . ref name vogel Yields may appear to be above 100 when products are impure. Purification steps always lower the yield and the reported yields usually refer to the yield of the final purified product. References reflist See also Quantum yield Category Stoichiometry chem stub ar de Ausbeute Chemie et Saagis es Rendimiento qu mico fr Rendement chimique id Rendemen kimia it Resa chimica ht Rannman an pousantaj nl Opbrengst scheikunde ja pl Wydajno reakcji chemicznej pt Rendimento q ... more details
mergeto Chemistry education date February 2012 General chemistry sometimes called gen chem for short is a course often taught at the high school and introductory university level. It is intended to serve as a broad introduction to a variety of concepts in chemistry and is widely taught. At the university level, it is also sometimes used as a weed out course for disciplines sometimes related, sometimes not which are perceived to require a high level of intellectual rigor or large course loads. It is also one of the few chemistry courses in most universities that does not explicitly explore a particular discipline such as organic chemistry or analytical chemistry . General chemistry courses typically introduce concepts such as stoichiometry , prediction of reaction products, thermodynamics , nuclear chemistry , electrochemistry , chemical kinetics , and many of the rudiments of physical chemistry . Though the list of subjects covered is typically broad, leading some to criticize both the class and the discipline as encouraging memorization, most general chemistry courses are firmly grounded in several fundamental physical rules for which the primary challenge is understanding when the rules are applicable. Concepts Taught To be later expanded to include brief descriptions of each discipline Stoichiometry Conservation of energy Conservation of mass Law of constant composition Gas law s Nuclear chemistry Solubility Acid base chemistry Chemical bonding Chemical kinetics Thermodynamics Electrochemistry Chemical equilibrium Chemical equilibria Category Natural sciences Chemistry Category Chemical education Category Chemistry ar be be x old de Allgemeine Chemie ja ru sv Allm n kemi tl Lahatang kapnayan uk ... more details
Crystal line materials mainly metal s and alloy s, but also stoichiometry stoichiometric salt s and other materials are made up of solid regions of ordered matter atoms placed in one of a number of ordered formations called Bravais lattice s . These regions are known as crystals. A perfect crystal is one that contains no point, linear, or planar imperfections. There are a wide variety of crystallographic defect s. The hypothetical concept of a perfect crystal is important in the basic formulation of the laws of thermodynamics . In crystallography , the phrase perfect crystal can be used to mean no line or planar defects , as it is difficult to measure small quantities of point defects in an otherwise defect free crystal. Imperfections are created due to gravity. In space and in zero gravity environments perfect crystals can be created as on the International Space Station . ref http www.newscientisttech.com article dn12467 magnetic gravity trick grows perfect crystals.html ref References reflist Category Crystals cs Ide ln krystal ja pl Kryszta doskona y ... more details
Orphan date February 2009 The latrunculins are a family of natural product s and toxin s produced by certain sea sponge sponge s, including genus Latrunculia , whence the name is derived. It binds actin monomers near the nucleotide binding cleft with 1 1 stoichiometry and prevents them from polymerize polymerizing . Administered in vivo , this effect results in disruption of the actin filaments of the cytoskeleton . This property has been used to great effect in the discovery of cadherin distribution regulation. References cite journal author Yarmola, E.G., Somasundaram, T., Boring, T.A., Spector, I., Bubb, M.R. title Actin Latrunculin A Structure and Function journal Journal of Biological Chemistry year 2000 volume 275 pages 28120&ndash 28127 pmid 10859320 issue 36 doi 10.1074 jbc.M004253200 Cell biology stub Category Actin inhibitors es Latrunculina nl Latrunculine ru ... more details
Plutonium carbide comes in several Stoichiometry stoichiometries PuC and Pu sub 2 sub C sub 3 sub . ref Cite book last Emel us first Harry Julius coauthors Alan G. Sharpe title Advances in inorganic chemistry and radiochemistry, Volume 12 publisher Academic Press year 1968 location New York, New York pages 205 206 url http books.google.com books?id SnCsg5jM kC&pg PA206&dq 22plutonium carbide 22&hl en&ei QljCTL2vKJGksQO3vYDmCw&sa X&oi book result&ct result&resnum 3&ved 0CDUQ6AEwAg v onepage&q 22plutonium 20carbide 22&f false ref It can be used as a nuclear fuel for nuclear reactors in conjunction with uranium carbide . The mixture is also labeled as uranium plutonium carbide UPuC . References Reflist Chemistry stub Plutonium compounds Category Carbides Category Plutonium compounds ru zh ... more details
has an ideal stoichiometric formula FeO, the actual stoichiometry is closer to Fe sub 0.95 sub O. The non stoichiometry occurs because of the ease of oxidation of Fe sup 2 sup to Fe sup 3 sup effectively .... But for practical purposes, the term describes materials where the non stoichiometry ... 1971 page 153 ref Defects vs non stoichiometry The cuprate superconductors highlight the concept of defect structures, which is related to non stoichiometry. YBa sub 2 sub Cu sub 3 sub O sub 7 x sub ... stoichiometry ABO sub 3 sub . For the cuprates, Y Ba occupy A sites whereas Cu occupies the B sites . The non defect material would have the stoichiometry YBa sub 2 sub Cu sub 3 sub O sub 9 sub ... the fact that stoichiometry is determined by the interior of crystals the surfaces of crystals often do not follow the stoichiometry of the bulk. The complex structures on surfaces are described by the term ... influenced by the defects associated with non stoichiometry. These defect sites provide pathways for atoms ... sensors and solid state batteries are two applications that rely on oxide vacancies. Non stoichiometry vs. inhomogeneity Non stoichiometry, which is change in the composition at the atomic scale, should ... more details
In chemistry the term stannate refers to compounds of tin Sn . Stannic acid Sn OH sub 4 sub , the formal precursor to stannates does not exist and is actually a hydrate of tin dioxide SnO sub 2 sub . The term is also used in naming conventions as a suffix for example the hexachlorostannate ion is SnCl sub 6 sub sup 2 sup . In materials science, two kinds of tin oxyanions are distinguished orthostannates contain discrete SnO sub 4 sub sup 4 sup units e.g. K sub 4 sub SnO sub 4 sub or have a spinel structure e.g. Mg sub 2 sub SnO sub 4 sub metastannates with a stoichiometry M sup II sup SnO sub 3 sub , M sup I sup sub 2 sub SnO sub 3 sub which may contain polymeric anions or may be sometimes better described as mixed oxides These materials are semiconductor s. ref Preparation, characterization and structure of metal stannates a new family of photocatalysts for organic pollutants degradation. Handbook of Photocatalysts 2010 , pp. 493 510. Nova Science Publishers, Inc., Hauppauge, N. Y ref References references Category Oxoanions Category Stannates Chem stub ... more details
Magnesium aluminide is an intermetallic compound of magnesium and aluminium . Common phases molecular structures include the beta phase Mg sub 2 sub Al sub 3 sub and the gamma phase Mg sub 17 sub Al sub 12 sub , which both have cubic crystal system cubic crystal structures. Magnesium aluminides are important constituents of 5XXX aluminium alloys aluminium magnesium and magnesium aluminium alloys, determining many of their engineering properties. MgAl has also been investigated for use as a reactant to produce metal hydride s in hydrogen storage technology. Like many intermetallics, MgAl compounds often have unusual stoichiometry stoichiometries with large and complex crystal structure unit cells . References cite journal journal Intermetallics volume 11 pages 373 376 year 2003 title Extended Homogeneity Range of Intermetallic Phases in Mechanically Alloyed Mg Al Alloys author D. Singh, C. Suryanarayana, L. Mertus, and R H. Chen doi 10.1016 S0966 9795 03 00005 0 inorganic compound stub Magnesium compounds Category Alloys Category Aluminides Category Magnesium compounds ... more details
2,3 Butanediol fermentation is wikt anaerobic anaerobic fermentation biochemistry fermentation of glucose with 2,3 butanediol as one of the end products. The overall stoichiometry of the reaction is 2 pyruvate NADH 2 carbon dioxide CO sub 2 sub 2,3 butanediol. Butanediol fermentation is typical for Enterobacter and is tested for using the Voges Proskauer VP test. The metabolic function of 2,3 butanediol is not known. Comparison with mixed acid fermentation 2,3 butanediol fermentation produces smaller amounts of acid than mixed acid fermentation , and butanediol, ethanol , carbon dioxide CO sub 2 sub and Dihydrogen H sub 2 sub are the end products. While equal amounts of CO sub 2 sub and H sub 2 sub are created during mixed acid fermentation, butanediol fermentation produces more than twice the amount of CO sub 2 sub because the gases are not produced only by formate hydrogen lyase like they are in the mixed acid fermentation References M.Madigan & J. Martinko, 11th edition, 2006 Brock s Biology of Microorganisms, NJ, Pearson Prentice Hall, p. 351 355 Links http biocyc.org META new image?type PATHWAY&object P125 PWY DEFAULTSORT Butanediol Fermentation Category Fermentation de 2,3 Butandiolg rung ... more details
Accuracy date February 2012 Tungsten pentoxide tungsten 2 oxygen 5 was reported in early literature but proved to have the stoichiometry W sub 18 sub O sub 49 sub . ref name Wells Wells A.F. 1984 Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0 19 855370 6 ref Sometimes called mineral blue, it is a blue solid formed by the reaction of tungsten trioxide, W sub 2 sub O sub 3 sub , and tungsten metal at 700 C. ref name Wells Intermediate oxides of tungsten There are a number of these unusual intermediate oxides formed from reacting metal and trioxide namely, W sub 20 sub O sub 58 sub , W sub 24 sub O sub 70 sub . ref name Wells W sub 18 sub O sub 49 sub contains both octahedral and pentagonal bipyramid al co ordination of the metal atom s by oxygen . ref name Wells See also Tungsten III oxide Tungsten IV oxide Tungsten VI oxide References reflist Tungsten compounds Category Tungstates Category Tungsten compounds Category Transition metal oxides inorganic compound stub ... more details
Lexitropsins ref cite journal author Sondhi S.M., Praveen Reddy B.S. and Lown J.W. title Lexitropsin conjugates Action on DNA targets journal Current medicinal chemistry volume 4 pages 313 358 year 1997 ref is a family of semi synthetic DNA binding ligands . They are analogs of natural antibiotics Netropsin and Distamycin . Antibiotics of this group are capable to bind with a narrow groove ref cite journal doi 10.1021 bi00051a013 author Goodsell D.S., Ng H.L., Kopka M.L., Lown J.W., Dickerson R.E. title Structure of a dicationic monoimidazole lexitropsin bound to DNA journal Biochemistry volume 34 pages 16654 61 year 1995 pmid 8527438 issue 51 ref of DNA with different sequence selectivity. ref cite journal author Goodsell D.S. title Sequence recognition of DNA by lexitropsins journal Curr Med Chem volume 8 pages 509 16 year 2001 pmid 11281838 issue 5 ref Lexitropsins form a complexes with DNA with stoichiometry 1 1 and 2 1. Based on the 2 1 complexes were obtained ligands with high sequence selectivity. Image Lexitropsins.png 600px Two groups of lexitropsins See also Netropsin Hoechst 33258 Pentamidine DNA binding protein Single strand binding protein List of nucleic acid simulation software Nucleic acid simulations References Reflist Category DNA binding proteins Category Molecular biology Category DNA binding substances ... more details
Proline rich proteins PRPs is a class of intrinsically unstructured protein s ref http www.springerlink.com content gt3j4l3147821671 Characterization, stoichiometry, and stability of salivary protein tannin complexes by ESI MS and ESI MS MS. Francis Canon, Franck Pat , Emmanuelle Meudec, Th r se Marlin, V ronique Cheynier, Alexandre Giuliani and Pascale Sarni Manchado, Analytical and Bioanalytical Chemistry, Volume 395, Number 8 d cembre 2009 ref IUP containing several repeats of a short proline rich sequence. Many tannin consuming animals secrete a tannin binding protein mucin in their saliva . Tannin binding capacity of salivary mucin is directly related to its proline content. Advantages in using salivary proline rich proteins PRPs to inactivate tannins are PRPs inactivate tannins to a greater extent than do dietary proteins this results in reduced fecal nitrogen losses, PRPs contain non specific nitrogen and nonessential amino acids this makes them more convenient for an animal to exploit rather than using up valuable dietary protein. ref http www.users.muohio.edu hagermae tannin.pdf Tanins chemistry on www.users.muohio.edu ref Example of this class of protein is protein IB5 IB5 , a human parotid salivary protein known to bind with polyphenols binding responsible for the astringency mouth feel . References reflist Category Proteins protein stub ... more details
The terms macrophage and microphage are used in ecology to describe heterotrophs that consume food in two different ways. Both macrophages and microphages ingest solid food and may process it through some sort of alimentary canal . ref name Sterner Sterner, R.W. and J.J. Elser. Ecological Stoichiometry The Biology of Elements from Molecules to the Biosphere. Princeton University Press, 2002. ref However, a macrophage handles food items singly, while a microphage handles food items in bulk without manipulating them individually. ref name Taghon Taghon, G.L. 1981. Beyond Selection Optimal Ingestion Rate as a Function of Food Value. The American Naturalist. 118 2 . ref Microphages include Filter feeder suspension feeders , and often incidentally digest low quality food items. ref name Sterner Another category of heterotrophs based on feeding mechanism, known as Osmotrophy osmotrophs , is made up of organisms primarily fungi and bacteria that absorb organism matter directly across their cell membranes. ref name Sterner The terms macrophage and microphage were originally used in this sense by Jordan and Hirsch 1927 cited in Yonge 1928 . ref name Taghon Although they have been used in ecology texts as recently as 2002, ref name Sterner the terms macrophage and microphage today are primarily used to describe two different types of white blood cells in the vertebrate immune system . References Reflist Category Eating behaviors ... more details
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