CARBON AND ITS COMPOUNDS
Carbo
For other uses, see Carbon (disambiguation).
6 boron ← carbon → nitrogen
-
↑
C
↓
Si
Periodic table - Extended periodic table
General
Name, symbol, number carbon, C, 6
Chemical series nonmetals
Group, period, block 14, 2, p
Appearance black (graphite)
colorless (diamond)
Standard atomic weight 12.0107(8) g·mol−1
Electron configuration 1s2 2s2 2p2
Electrons per shell 2, 4
Physical properties
Phase solid
Density (near r.t.) (graphite) 1.9-2.3[1] g·cm−3
Density (near r.t.) (diamond) 3.5-3.53[1] g·cm−3
Density (near r.t.) (fullerene) 1.69[1] g·cm−3
Heat of fusion (graphite) ? 100 kJ·mol−1
Heat of fusion (diamond) ? 120 kJ·mol−1
Heat of vaporization 715 kJ·mol−1
Specific heat capacity (25 °C) (graphite)
8.517 J·mol−1·K−1
Specific heat capacity (25 °C) (diamond)
6.115 J·mol−1·K−1
Vapor pressure (graphite) P/Pa 1 10 100 1 k 10 k 100 k
at T/K 2839 3048 3289 3572 3908
Atomic properties
Crystal structure (graphite) hexagonal
Oxidation states 4, 3 [2], 2, 1 [3], 0, -1, -2, -3, -4[4]
(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJ·mol−1
2nd: 2352.6 kJ·mol−1
3rd: 4620.5 kJ·mol−1
Atomic radius 70 pm
Atomic radius (calc.) 67 pm
Covalent radius 77 pm
Van der Waals radius 170 pm
Miscellaneous
Magnetic ordering diamagnetic
Electrical resistivity (graphite) 1.375*10-5 [5]Ω·m
Thermal conductivity (300 K) (graphite)
(80–230) W·m−1·K−1
Thermal conductivity (300 K) (diamond)
(900–2320) W·m−1·K−1
Thermal diffusivity (300 K) (diamond)
(503–1300) mm²/s
Mohs hardness (graphite) 1-2 [6]
Mohs hardness (diamond) 10.0 [6]
CAS registry number 7440-44-0
Selected isotopes
Main article: Isotopes of carbon iso NA half-life DM DE (MeV) DP
15
12C 98.9% 12C is stable with 6 neutrons
13C 1.1% 13C is stable with 7 neutrons
14C trace 5730 y beta- 0.156 14N
References
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Carbon (pronounced /kɑɹbən/) is a chemical element with the symbol C and atomic number is 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5700 years.[7] Carbon is one of the few elements known to man since antiquity.[8][9] The name "carbon" comes from Latin language carbo, coal, and, in some Romance languages, the word carbon can refer both to the element and to coal.
There are several allotropes of carbon of which the best known are graphite, diamond, and amorphous carbon.[10] The physical properties of carbon vary widely with the allotropic form. For example, diamond is highly transparent, while graphite is opaque and black. Diamond is among the hardest materials known, while graphite is soft enough to form a streak on paper. Diamond has a very low electric conductivity, while graphite is a very good conductor. Also, diamond has the highest thermal conductivity of all known materials under normal conditions. All the allotropic forms are solids under normal conditions but graphite is the most thermodynamically stable.
All forms of carbon are highly stable, requiring high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and other transition metal carbonyl complexes. The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil and methane clathrates. Carbon forms more compounds than any other element, with almost ten million pure organic compounds described to date, which in turn are a tiny fraction of such compounds that are theoretically possible under standard conditions.[11]
Carbon is the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body, carbon is the second most abundant element by mass (about 18.5%) after oxygen.[12] This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.
Contents
[hide]
* 1 Characteristics
o 1.1 Allotropes
o 1.2 Occurrence
o 1.3 Isotopes
o 1.4 Formation in stars
o 1.5 Carbon cycle
* 2 Compounds
o 2.1 Inorganic compounds
o 2.2 Organic compounds
* 3 History and etymology
o 3.1 Applications
* 4 Production
o 4.1 Graphite Production
* 5 Precautions
* 6 See also
* 7 References
* 8 External links
[edit] Characteristics
The different forms or allotropes of carbon (see below) include the hardest naturally occurring substance, diamond, and also one of the softest known substances, graphite. Moreover, it has an affinity for bonding with other small atoms, including other carbon atoms, and is capable of forming multiple stable covalent bonds with such atoms. As a result, carbon is known to form nearly ten million different compounds; the large majority of all chemical compounds.[11] Carbon also has the highest melting and sublimation point of all elements.[citation needed] At atmospheric pressure it has no actual melting point as its triple point is at 10 MPa (100 bar) so it sublimates above 4000 K.[citation needed] Carbon sublimes in a carbon arc which has a temperature of about 5800K. Thus, irrespective of its allotropic form, carbon remains solid at higher temperatures than the highest melting point metals such as tungsten or rhenium. Although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature.
Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.
Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure.
Carbon compounds form the basis of all life on Earth and the carbon-nitrogen cycle provides some of the energy produced by the Sun and other stars. Although it forms an extraordinary variety of compounds, most forms of carbon are comparatively unreactive under normal conditions. At standard temperature and pressure, it resists all but the strongest oxidizers. It does not react with sulfuric acid, hydrochloric acid, chlorine or any alkalis. At elevated temperatures carbon reacts with oxygen to form carbon oxides, and will reduce such metal oxides as iron oxide to the metal. This exothermic reaction is used in the iron and steel industry to control the carbon content of steel:
Fe3O4 + 4C(s) → 3Fe(s) + 4CO(g)
with sulfur to form carbon disulfide and with steam in the coal-gas reaction
C(s) + H2O(g) → CO(g) + H2(g).
Carbon combines with some metals at high temperatures to form metallic carbides, such as the iron carbide cementite in steel, and tungsten carbide, widely used as an abrasive and for making hard tips for cutting tools.
The system of carbon allotropes spans a range of extremes:
Synthetic diamond nanorods are the hardest materials known. Graphite is one of the softest materials known.
Diamond is the ultimate abrasive. Graphite is a very good lubricant.
Diamond is an excellent electrical insulator. Graphite is a conductor of electricity.
Diamond is the best known thermal conductor Some forms of graphite are used for thermal insulation (i.e. firebreaks and heatshields)
Diamond is highly transparent. Graphite is opaque.
Diamond crystallizes in the cubic system. Graphite crystallizes in the hexagonal system.
Amorphous carbon is completely isotropic. Carbon nanotubes are among the most anisotropic materials ever produced.
[edit] Allotropes
Main article: Allotropes of carbon
Atomic carbon is a very short-lived species and therefore, carbon is stabilized in various multi-atomic structures with different molecular configurations called allotropes. The three relatively well-known allotropes of carbon are amorphous carbon, graphite, and diamond. Once considered exotic, fullerenes are nowadays commonly synthesized and used in research; they include buckyballs,[13][14] carbon nanotubes,[15] carbon nanobuds[16] and nanofibers[17].[18] Several other exotic allotropes have also been discovered, such as aggregated diamond nanorods,[19] lonsdaleite,[20] glassy carbon,[21] carbon nanofoam[22] and linear acetylenic carbon.[23]
* The amorphous form, is an assortment of carbon atoms in a non-crystalline, irregular, glassy state, which is essentially graphite but not held in a crystalline macrostructure. It is present as a powder, and is the main constituent of substances such as charcoal, lampblack (soot) and activated carbon.
* At normal pressures carbon takes the form of graphite, in which each atom is bonded trigonally to three others in a plane composed of fused hexagonal rings, just like those in aromatic hydrocarbons. The resulting network is 2-dimensional, and the resulting flat sheets are stacked and loosely bonded through weak Van der Waals forces. This gives graphite its softness and its cleaving properties (the sheets slip easily past one another). Because of the delocalization of one of the outer electrons of each atom to form a π-cloud, graphite conducts electricity, but only in the plane of each covalently bonded sheet. This results in a lower bulk electrical conductivity for carbon than for most metals. The delocalization also accounts for the energetic stability of graphite over diamond at room temperature.
Some allotropes of carbon: a) diamond; b) graphite; c) lonsdaleite; d-f) fullerenes (C60, C540, C70); g) amorphous carbon; h) carbon nanotube.
Some allotropes of carbon: a) diamond; b) graphite; c) lonsdaleite; d-f) fullerenes (C60, C540, C70); g) amorphous carbon; h) carbon nanotube.
* At very high pressures carbon forms the more compact allotrope diamond, having nearly twice the density of graphite. Here, each atom is bonded tetrahedrally to four others, thus making a 3-dimensional network of puckered six-membered rings of atoms. Diamond has the same cubic structure as silicon and germanium and, thanks to the strength of the carbon-carbon bonds is the hardest naturally occurring substance in terms of resistance to scratching. Contrary to the popular belief that "diamonds are forever", they are in fact thermodynamically unstable under normal conditions and transform into graphite.[10] But due to a high activation energy barrier, the transition into graphite is so extremely slow at room temperature as to be unnoticeable.
* Under some conditions, carbon crystallizes as lonsdaleite. This form is similar to diamond but has a hexagonal crystal lattice.[20]
* Fullerenes have a graphite-like structure, but instead of purely hexagonal packing, they also contain pentagons (or even heptagons) of carbon atoms, which bend the sheet into spheres, ellipses or cylinders. The properties of fullerenes (split into buckyballs, buckytubes and nanobuds) have not yet been fully analyzed and represents an intense area of research in nanomaterials. The name "fullerene" is given after Richard Buckminster Fuller, developer of some geodesic domes,[citation needed] which resemble the structure of fullerenes. The buckyballs are fairly large molecules formed completely of carbon bonded trigonally, forming spheroids (the best-known and simplest is the soccerball-shaped structure C60 buckminsterfullerene).[13] Carbon nanotubes are structurally similar to buckyballs, except that each atom is bonded trigonally in a curved sheet that forms a hollow cylinder.[14][15] Nanobuds were first published in 2007 and are hybrid bucky tube/buckyball materials (buckyballs are covalently bonded to the outer wall of a nanotube) that combine the properties of both in a single structure.[16]
* Of the other discovered allotropes, aggregated diamond nanorods were synthesised in 2005 and are believed to be the hardest substance known yet.[24] Carbon nanofoam is a ferromagnetic allotrope discovered in 1997. It consists of a low-density cluster-assembly of carbon atoms strung together in a loose three-dimensional web, in which the atoms are bonded trigonally in six- and seven-membered rings. It is among the lightest known solids, with a density of about 2 kg/m³.[25] Similarly, glassy carbon contains a high proportion of closed porosity.[21] But unlike normal graphite, the graphitic layers are not stacked like pages in a book, but have a more random arrangement. Linear acetylenic carbon[23] has the chemical structure[26] -(C:::C)n- .Carbon in this modification is linear with sp orbital hybridisation, and is a polymer with alternating single and triple bonds. This type of carbyne is of considerable interest to nanotechnology as its Young's modulus is forty times that of the hardest known material - diamond.[27]
[edit] Occurrence
Graphite ore
Graphite ore
Raw diamond crystal.
Raw diamond crystal.
Carbon is the fourth most abundant chemical element in the universe by mass after hydrogen, helium, and oxygen. Carbon is abundant in the Sun, stars, comets, and in the atmospheres of most planets. Some meteorites contain microscopic diamonds that were formed when the solar system was still a protoplanetary disk. Microscopic diamonds may also be formed by the intense pressure and high temperature at the sites of meteorite impacts.[28]
"Present day" (1990s) sea surface dissolved inorganic carbon concentration (from the GLODAP climatology)
"Present day" (1990s) sea surface dissolved inorganic carbon concentration (from the GLODAP climatology)
In combination with oxygen in carbon dioxide, carbon is found in the Earth's atmosphere (in quantities of approximately 810 gigatonnes) and dissolved in all water bodies (approximately 36000 gigatonnes). Around 1900 gigatonnes are present in the biosphere. Hydrocarbons (such as coal, petroleum, and natural gas) contain carbon as well — coal "reserves" (not "resources") amount to around 900 gigatonnes, and oil reserves around 150 gigatonnes. With smaller amounts of calcium, magnesium, and iron, carbon is a major component of very large masses carbonate rock (limestone, dolomite, marble etc.).
Coal is a significant commercial source of mineral carbon; anthracite containing 92-98% carbon[citation needed] and the largest source (4000 Gt, or 80% of coal, gas and oil reserves) of carbon in a form suitable for use as fuel.[29]
Graphite is found in large quantities in New York and Texas, the United States, Russia, Mexico, Greenland, and India.
Natural diamonds occur in the rock kimberlite, found in ancient volcanic "necks," or "pipes". Most diamond deposits are in Africa, notably in South Africa, Namibia, Botswana, the Republic of the Congo, and Sierra Leone. There are also deposits in Arkansas, Canada, the Russian Arctic, Brazil and in Northern and Western Australia.
Diamonds are now also being recovered from the ocean floor off the Cape of Good Hope. However, though diamonds are found naturally, about 30% of all industrial diamonds used in the U.S. are now made synthetically.
According to studies from the Massachusetts Institute of Technology, an estimate of the global carbon budget is:[citation needed]
Biosphere, oceans, atmosphere
0.45 x 1018 kilograms (3.7 x 1018 moles)
Crust
Organic carbon 13.2 x 1018 kg
Carbonates 62.4 x 1018 kg
Mantle
1200 x 1018 kg
Carbon-14 is formed in upper layers of the troposphere and the stratosphere, at altitudes of 9–15 km, by a reaction that is precipitated by cosmic rays. Thermal neutrons are produced that collide with the nuclei of nitrogen-14, forming carbon-14 and a proton.
[edit] Isotopes
Main article: Isotopes of carbon
Isotopes of carbon are atomic nuclei that contain six protons plus a number of neutrons (varying from 2 to 16). Carbon has two stable, naturally occurring isotopes.[7] The isotope carbon-12 (12C) forms 98.93% of the carbon on Earth, while carbon-13 (13C) forms the remaining 1.07%.[7] The concentration of 12C is further increased in biological materials because biochemical reactions discriminate against 13C.[30] In 1961 the International Union of Pure and Applied Chemistry (IUPAC) adopted the isotope carbon-12 as the basis for atomic weights.[31] Identification of carbon in NMR experiments is done with the isotope 13C.
Carbon-14 (14C) is a naturally occurring radioisotope which occurs in trace amounts on Earth of up to 1 part per trillion (0.0000000001%), mostly confined to the atmosphere and superficial deposits, particularly of peat and other organic materials.[32] This isotope decays by 0.158 MeV β- emission. Because of its relatively short half-life of 5730 years, 14C is virtually absent in ancient rocks, but is created in the upper atmosphere (lower stratosphere and upper troposphere) by interaction of nitrogen with cosmic rays.[33] The abundance of 14C in the atmosphere and in living organisms is almost constant, but decreases predictably in their bodies after death. This principle is used in radiocarbon dating, invented in 1949, which has been used extensively to determine the age of carbonaceous materials with ages up to about 40,000 years.[34][35]
There are 15 known isotopes of carbon and the shortest-lived of these is 8C which decays through proton emission and alpha decay and has a half-life of 1.98739x10-21 s.[36] The exotic 19C exhibits a nuclear halo, which means its radius is appreciably larger than would be expected if the nucleus was a sphere of constant density.[37]
[edit] Formation in stars
Main articles: Triple-alpha process and CNO cycle
Formation of the carbon atomic nucleus requires a nearly simultaneous triple collision of alpha particles (helium nuclei) within the core of a giant or supergiant star. This happens in conditions of temperature and helium concentration that the rapid expansion and cooling of the early universe prohibited, and therefore no significant carbon was created during the Big Bang. Instead, the interiors of stars in the horizontal branch transform three helium nuclei into carbon by means of this triple-alpha process. In order to be available for formation of life as we know it, this carbon must then later be scattered into space as dust, in supernova explosions, as part of the material which later forms second- and third-generation star systems which have planets accreted from such dust. The Solar System is one such third-generation star system.
One of the fusion mechanisms powering stars is the carbon-nitrogen cycle.
Rotational transitions of various isotopic forms of carbon monoxide (e.g. 12CO, 13CO, and C18O) are detectable in the submillimeter regime, and are used in the study of newly forming stars in molecular clouds.
[edit] Carbon cycle
Main article: Carbon cycle
Diagram of the carbon cycle. The black numbers indicate how much carbon is stored in various reservoirs, in billions of tons ("GtC" stands for gigatons of carbon; figures are circa 2004). The purple numbers indicate how much carbon moves between reservoirs each year. The sediments, as defined in this diagram, do not include the ~70 million GtC of carbonate rock and kerogen.
Diagram of the carbon cycle. The black numbers indicate how much carbon is stored in various reservoirs, in billions of tons ("GtC" stands for gigatons of carbon; figures are circa 2004). The purple numbers indicate how much carbon moves between reservoirs each year. The sediments, as defined in this diagram, do not include the ~70 million GtC of carbonate rock and kerogen.
Under terrestrial conditions, conversion of one element to another is very rare. Therefore, the amount of carbon on Earth is effectively constant. Thus, processes that use carbon must obtain it somewhere and dispose of it somewhere else. The paths that carbon follows in the environment make up the carbon cycle. For example, plants draw carbon dioxide out of their environment and use it to build biomass, as in carbon respiration or the Calvin cycle, a process of carbon fixation. Some of this biomass is eaten by animals, whereas some carbon is exhaled by animals as carbon dioxide. The carbon cycle is considerably more complicated than this short loop; for example, some carbon dioxide is dissolved in the oceans; dead plant or animal matter may become petroleum or coal, which can burn with the release of carbon, should bacteria not consume it.
[edit] Compounds
[edit] Inorganic compounds
Main article: Compounds of carbon
Commonly carbon-containing compounds which are associated with minerals or which do not contain hydrogen or fluorine, are treated separately from classical organic compounds; however the definition is not rigid (see reference articles above). Among these are the simple oxides of carbon. The most prominent oxide is carbon dioxide (CO2). This was once the principal constituent of the paleoatmosphere, but is a minor component of the Earth's atmosphere today.[38] Dissolved in water, it forms carbonic acid (H2CO3), but as most compounds with multiple single-bonded oxygens on a single carbon it is unstable.[citation needed] Through this intermediate, though, resonance-stabilized carbonate ions are produced. Some important minerals are carbonates, notably calcite. Carbon disulfide (CS2) is similar.
The other common oxide is carbon monoxide (CO). It is formed by incomplete combustion, and is a colorless, odorless gas. The molecules each contain a triple bond and are fairly polar, resulting in a tendency to bind permanently to hemoglobin molecules, displacing oxygen, which has a lower binding affinity.[39][40] Cyanide (CN–), has a similar structure, but behaves much like a halide ion (pseudohalogen). For example it can form the nitride cyanogen molecule ((CN)2), similar to diatomic halides. Other uncommon oxides are carbon suboxide (C3O2),[41] the unstable dicarbon monoxide (C2O),[42][43] and even carbon trioxide (CO3).[44][45]
With reactive metals, such as tungsten, carbon forms either carbides (C4–), or acetylides (C22–) to form alloys with high melting points. These anions are also associated with methane and acetylene, both very weak acids. With an electronegativity of 2.5,[46] carbon prefers to form covalent bonds. A few carbides are covalent lattices, like carborundum (SiC), which resembles diamond.
[edit] Organic compounds
Main article: Organic compound
Structural formula of methane, the simplest possible organic compound
Structural formula of methane, the simplest possible organic compound
Carbon has the ability to form very long chains interconnecting C-C bonds. This property is called catenation. Carbon-carbon bonds are strong, and stable.[citation needed] This property allows carbon to form an almost infinite number of compounds; in fact, there are more known carbon-containing compounds than all the compounds of the other chemical elements combined except those of hydrogen (because almost all organic compounds contain hydrogen too).
The simplest form of an organic molecule is the hydrocarbon—a large family of organic molecules that are composed of hydrogen atoms bonded to a chain of carbon atoms. Chain length, side chains and functional groups all affect the properties of organic molecules. By IUPAC's definition, all the other organic compounds are functionalized compounds of hydrocarbons.[citation needed]
Carbon is the basis for all plastic materials that are used in common household items.
Carbon is the basis for all plastic materials that are used in common household items.
Carbon occurs in all organic life and is the basis of organic chemistry. When united with hydrogen, it forms various flammable compounds called hydrocarbons which are important to industry as chemical feedstock for the manufacture of plastics, petrochemicals and as fossil fuels.
When combined with oxygen and hydrogen, carbon can form many groups of important biological compounds including sugars, celluloses, lignans, chitins, alcohols, fats, and aromatic esters, carotenoids and terpenes. With nitrogen it forms alkaloids, and with the addition of sulfur also it forms antibiotics, amino acids and proteins. With the addition of phosphorus to these other elements, it forms DNA and RNA, the chemical codes of life, and adenosine triphosphate (ATP), the most important energy-transfer molecules in all living cells.
[edit] History and etymology
Please help improve this section by expanding it. Further information might be found on the talk page or at requests for expansion. (January 2008)
The English name carbon comes from the Latin carbo for coal and charcoal,[47] and hence comes French charbon, meaning charcoal. In German, Dutch and Danish, the names for carbon are Kohlenstoff, koolstof and kulstof respectively, all literally meaning coal-substance.
Carl Wilhelm Scheele
Carl Wilhelm Scheele
Antoine Lavoisier in his youth
Antoine Lavoisier in his youth
Carbon was discovered in prehistory and was known in the forms of soot and charcoal to the earliest human civilizations. Diamonds were known probably as early as 2500 BCE in China, while carbon in the forms of charcoal was made around Roman times by the same chemistry as it is today, by heating wood in a pyramid covered with clay to exclude air.[48][49]
In 1722, René A. F. de Réaumur demonstrated that iron was transformed into steel through the absorption of some substance, now known to be carbon.[50] In 1772, Antoine Lavoisier showed that diamonds are a form of carbon, when he burned samples of carbon and diamond then showed that neither produced any water and that both released the same amount of carbon dioxide per gram. Carl Wilhelm Scheele showed that graphite, which had been thought of as a form of lead, was instead a type of carbon.[51] In 1786, the French scientists Claude Louis Berthollet, Gaspard Monge and C. A. Vandermonde then showed that this substance was carbon.[52] In their publication they proposed the name carbone (Latin carbonum) for this element. Antoine Lavoisier listed carbon as an element in his 1789 textbook.[53]
A new allotrope of carbon, fullerene, that was discovered in 1985[54] includes nanostructured forms such as buckyballs and nanotubes.[13] Their discoverers received the Nobel Prize in Chemistry in 1996.[55] The resulting renewed interest in new forms, lead to the discovery of further exotic allotropes, including glassy carbon, and the realization that "amorphous carbon" is not strictly amorphous.[21]
[edit] Applications
Pencil lead for mechanical pencils are made of graphite.
Pencil lead for mechanical pencils are made of graphite.
Sticks of vine and compressed charcoal.
Sticks of vine and compressed charcoal.
A cloth of woven carbon filaments
A cloth of woven carbon filaments
Silicon carbide single crystal
Silicon carbide single crystal
The C60 fullerene in crystalline form
The C60 fullerene in crystalline form
Tungsten carbide milling bits
Tungsten carbide milling bits
Carbon is essential to all known living systems, and without it life as we know it could not exist (see alternative biochemistry). The major economic use of carbon other than food and wood is in the form of hydrocarbons, most notably the fossil fuel methane gas and crude oil (petroleum). Crude oil is used by the petrochemical industry to produce, amongst others, gasoline and kerosene, through a distillation process, in refineries. Cellulose is a natural, carbon-containing polymer produced by plants in the form of cellulose, cotton, linen, hemp. Commercially valuable carbon polymers of animal origin include wool, cashmere and silk. Plastics are made from synthetic carbon polymers, often with oxygen and nitrogen atoms included at regular intervals in the main polymer chain. The raw materials for many of these synthetic substances come from crude oil.
The uses of carbon and its compounds are extremely varied. It can form alloys with iron, of which the most common is carbon steel. Graphite is combined with clays to form the 'lead' used in pencils used for writing and drawing. It is also used as a lubricant and a pigment, as a moulding material in glass manufacture, in electrodes for dry batteries and in electroplating and electroforming, in brushes for electric motors and as a neutron moderator in nuclear reactors.
Charcoal is used as a drawing material in artwork, for grilling, and in many other uses including iron smelting. Wood, coal and oil are used as fuel for production of energy and space heating. Gem quality diamond is used in jewelry, and Industrial diamonds are used in drilling, cutting and polishing tools for machining metals and stone. Plastics are made from fossil hydrocarbons, and carbon fibre, made by pyrolysis of synthetic polyester fibres is used to reinforce plastics to form advanced, lightweight composite materials. Carbon fiber is made by pyrolysis of extruded and stretched filaments of polyacrylonitrile (PAN) and other organic substances. The crystallographic structure and mechanical properties of the fiber depend on the type of starting material, and on the subsequent processing. Carbon fibres made from PAN have structure resembling narrow filaments of graphite, but thermal processing may re-order the structure into a continuous rolled sheet[citation needed]. The result is fibers with higher specific tensile strength than steel.[citation needed]
Carbon black is used as the black pigment in printing ink, artist's oil paint and water colours, carbon paper, automotive finishes, India ink and laser printer toner. Carbon black is also used as a filler in rubber products such as tyres and in plastic compounds. Activated charcoal is used as an absorbent and adsorbent in filter material in applications as diverse as gas masks, water purification and kitchen extractor hoods and in medicine to absorb toxins, poisons, or gases from the digestive system. Carbon is used in chemical reduction at high temperatures. coke is used to reduce iron ore into iron. Case hardening of steel is achieved by heating finished steel components in carbon powder. Carbides of silicon, tungsten, boron and titanium, are among the hardest known materials, and are used as abrasives in cutting and grinding tools. Carbon compounds make up most of the materials used in clothing, such as natural and synthetic textiles and leather, and almost all of the interior surfaces in the built environment other than glass, stone and metal.
[edit] Production
Please help improve this section by expanding it. Further information might be found on the talk page or at requests for expansion. (December 2007)
[edit] Graphite Production
Commercially viable natural deposits of graphite occur in many parts of the world, but the most important sources economically are in China, India, Brazil, and North Korea.[56] Graphite deposits are of metamorphic origin, found in association with quartz, mica and feldspars in schists, gneisses and metamorphosed sandstones and limestone as lenses or veins, sometimes of a metre or more in thickness. Deposits of graphite in Borrowdale, Cumberland, England were at first of sufficient size and purity that, until the 1800s, pencils were made simply by sawing blocks of natural graphite into strips before encasing the strips in wood. Today, smaller deposits of graphite are obtained by crushing the parent rock and floating the lighter graphite out on water.
[edit] Precautions
Pure carbon has extremely low toxicity and can be handled and even ingested safely in the form of graphite or charcoal. It is resistant to dissolution or chemical attack, even in the acidic contents of the digestive tract, for example. Consequently if it gets into body tissues it is likely to remain there indefinitely. Carbon black was probably one of the first pigments to be used for tattooing, and Ötzi the Iceman was found to have carbon tattoos that survived during his life and for 5200 years after his death.[57] However, inhalation of coal dust or soot (carbon black) in large quantities can be dangerous, irritating lung tissues and causing the congestive lung disease coalworker's pneumoconiosis. Similarly, diamond dust used as an abrasive can do harm if ingested or inhaled. Microparticles of carbon are produced in diesel engine exhaust fumes, and may accumulate in the lungs.[58] In these examples, the harmful effects may result from contamination of the carbon particles, with organic chemicals or heavy metals for example, rather than from the carbon itself.
Carbon may also burn vigorously and brightly in the presence of air at high temperatures, as in the Windscale fire, which was caused by sudden release of stored Wigner energy in the graphite core. Large accumulations of coal, which have remained inert for hundred of millions of years in the absence of oxygen, may spontaneously combust when exposed to air, for example in coal mine waste tips.
The great variety of carbon compounds include such lethal poisons as tetrodotoxin, the lectin ricin from seeds of the castor oil plant Ricinus communis, cyanide (CN-) and carbon monoxide; and such essentials to life as glucose and protein.Compounds of carbon
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There is an immense number of distinct compounds that contain carbon atoms. Some sources suggest that this number is close to almost ten million known.[1] However, it is possible that the number is greater.
Contents
[hide]
* 1 Organic compounds
* 2 Inorganic compounds
o 2.1 Compounds with other nonmetals
o 2.2 Compounds with metals
+ 2.2.1 Carbonates and bicarbonates
+ 2.2.2 Carbonyls
+ 2.2.3 Compounds contanining the CN group
+ 2.2.4 Carbides
+ 2.2.5 Other
* 3 Alloys
* 4 Formation of carbon compounds
* 5 References
* 6 See also
[edit] Organic compounds
Main article: Organic compound
Every organic compound contains at least one atom of carbon. The number of these compounds is immense and the described number of defined compounds is close to 10 million. However, an indefinitely larger number of such compounds are theoretically possible.
There are several organic compounds sometimes considered as inorganic: NH2COONH4, COCl2, CSCl2, CS(NH2)2, CO(NH2)2
[edit] Inorganic compounds
See also: Inorganic compounds by element#Carbon
There is a rich variety of carbon chemistry that does not fall within the realm of organic chemistry and is thus called inorganic carbon chemistry.
[edit] Compounds with other nonmetals
Perhaps the best known are the oxides of carbon, carbon dioxide (CO2) and carbon monoxide (CO). Other known oxides are the uncommon carbon suboxide, C3O2, the uncommon dicarbon monoxide, C2O and even the exotic carbon trioxide (CO3).
Other (binary) compounds of carbon with nonmetals include: CS2, β-C3N4, CBr4, CCl4, CF4, COF2, COS, H2C2B10H10,
[edit] Compounds with metals
[edit] Carbonates and bicarbonates
Main articles: Carbonic acid, Carbonate, and Bicarbonate
The only known acid that is derived from the oxides of carbon is the carbonic acid (H2CO3). Upon monodeprotonation of this acid, bicarbonates are formed, which can be further derpotonated to carbonates.
Here is a list of carbonates and bicarbonates: NH4HCO3, (NH4)2CO3, BaCO3, CdCO3, Cs2CO3, Ca(HCO3)3, CaCO3, Ce2(CO3)3, CoCO3, CuCO3, FeCO3, PbCO3, La2(CO3)3, Li2CO3, MgCO3, MnCO3, NiCO3, KHCO3, K2CO3, Ag2CO3, NaHCO3, Na2CO3, SrCO3, ZnCO3
[edit] Carbonyls
Main article: Carbonyl
Carbonyls are coordination complexes between transition metals and carbonyl ligands. Metal carbonyls are complexes that are formed with the neutral ligand CO. These complexes are covalent. Here is a list of some carbonyls: Cr(CO)6, Co2(CO)8, Fe(CO)5, Mn2(CO)10, Mo(CO)6, Ni(CO)4, W(CO)6,
[edit] Compounds contanining the CN group
Main articles: Cyanide, Cyanates, Thiocyanate, and Isocyanate
Other types of inorganic compounds include inorganic salts and complexes of the carbon-containing polyatomic ions cyanide, isocyanide, cyanate, thiocyanate.
NH4SCN, CaNCN, Co(SCN)2, CuCN, (HCNO)x NH2CN HCNO, (CN)2, BrCN, ClCN, HCN, KOCN, KCN, K3Fe(CN)6, K4Fe(CN)6, KSCN, Fe4(Fe(CN)6)3, AgCN, NaOCN, NaCN, Na3Fe(CN)5NO, NaSCN, (SCN)2,
[edit] Carbides
Main article: Carbide
Carbides are binary compounds of carbon with an element that is less electronegative than it. B4C, CaC2 SiC, TaC, TiC, WC,
[edit] Other
The known inorganic chemistry of the allotropes of carbon (diamond, graphite, and the fullerenes) blossomed with the discovery of buckminsterfullerene in 1985, as additional fullerenes and their various derivatives were discovered. One such class of derivatives is inclusion compounds, in which an ion is enclosed by the all-carbon shell of the fullerene. This inclusion is denoted by the "@" symbol. For example, an ion consisting of a lithium ion trapped within buckminsterfullerene would be denoted Li+@C60. As with any other ionic compound, this complex ion could in principle pair with a counterion to form a salt.
[edit] Alloys
There are several alloys that contain carbon of which the best known alloy is carbon steel (see category:steels)). Besides steel, other alloys based on iron and carbon are: anthracite iron, cast iron, pig iron, wrought iron, but also spiegeleisen (which contains also manganese). Stellite is an alloy of carbon with cobalt, chromium and tungsten. To some degree, these alloys could be considered carbides.
[edit] Formation of carbon compounds
In organic chemistry there are 3 important elements: Carbon, Oxygen and Hydrogen. Each of these elements have different kinds of bonds. Carbon atom has tetravalent bonds, Oxygen atoms divalent bonds and Hydrogen monovalent bonds.Organic compound
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Methane is the simplest possible organic compound
Methane is the simplest possible organic compound
An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered inorganic. The division between "organic" and "inorganic" carbon compounds while "useful in organizing the vast subject of chemistry...is somewhat arbitrary"[1].
Organic chemistry is the science concerned with all aspects of organic compounds. Organic synthesis is the methodology of their preparation.
Contents
[hide]
* 1 History
* 2 Classification
o 2.1 Natural compounds
o 2.2 Synthetic compounds
* 3 Nomenclature
* 4 Databases
* 5 Structure determination
* 6 See also
* 7 References
[edit] History
The "organic" is a historical name, dating back to 19th century, when it was believed that organic compounds could only be synthesized in living organisms through vis vitalis - the "life-force". The theory that organic compounds were fundamentally different from those that were "inorganic", that is, not synthesized through a life-force, was disproved with the synthesis of urea, an "organic" compound by definition of its known occurrence only in the urine of living organisms, from potassium cyanate and ammonium sulfate by Friedrich Wöhler in the Wöhler synthesis. The kinds of carbon compounds that are still traditionally considered inorganic are those that were considered inorganic before Wöhler's time; that is, those which came from "inorganic" (i.e., lifeless) sources such as minerals.[1]
[edit] Classification
See Organic chemistry#Classification of organic substances
Organic compounds may contain atoms of further elements, so-called heteroatoms. Organometallic compounds constitute a further subsection, characterized by covalent bonds between organic carbon and a metal.
There is also a large number of inorganic carbon compounds to distinguish from organic compounds.
[edit] Natural compounds
An important subset of organic compounds is still extracted from natural sources because they would be far too expensive to be produced artificially. Examples include most sugars, some alkaloids and terpenoids, certain nutrients such as vitamin B12, and in general, those natural products with large or stereoisometrically complicated molecules which are present in reasonable concentrations in living organisms.
Further compounds of prime importance in biochemistry are antigens, carbohydrates, enzymes, hormones, lipids and fatty acids, neurotransmitters, nucleic acids, proteins, peptides and amino acids, vitamins and fats and oils.
[edit] Synthetic compounds
Many polymers, including all plastics are organic compounds.
[edit] Nomenclature
The IUPAC nomenclature of organic compounds slightly differs from the CAS nomenclature.
[edit] Databases
* The CAS database is the most comprehensive repository for data on organic compounds. The search tool SciFinder is offered .
* The Beilstein database contains information on 9.8 million substances, covers the scientific literature from 1771 to the present, and is today accessible via CrossFire. Structures and a large diversity of physical and chemical properties is available for each substance, with reference to original literature.
* PubChem contains 18.4 million entries on compounds and especially covers the field of medicinal chemistry.
There is a great number of more specialized databases for diverse branches of organic chemistry.
[edit] Structure determination
See Structure determination
Today, the main tools are proton and carbon-13 NMR spectroscopy and X-ray crystallography.List of organic compounds
From Wikipedia, the free encyclopedia
Jump to: navigation, search
This page aims to list well-known organic compounds, including organometallic compounds, to stimulate the creation of Wikipedia articles. Note that purely inorganic compounds, minerals, and chemical elements are not included on this list. There are also no generic terms (e.g., carbohydrate) or mixtures of no fixed composition (e.g., naphtha, gasoline). Compounds and enzymes that are overwhelmingly of interest to biochemists, such as Cytochrome c peroxidase, are listed under list of biomolecules.
This list is not necessarily complete or up to date — if you see an article that should be here but isn't (or one that shouldn't be here but is), please update the page accordingly.
For substances with a number prefix such as 2-Butanol or 1,3-Cyclohexadiene, please use the first letter of the name (in this case under B or C) to find the compound. Note that such names usually have the first letter capitalized in a title or at the beginning of a sentence.
Relevant links for chemical compounds are:
* The CAS Substance Databases, which contains information on about 23 million compounds
* ChemIDplus [1] is a useful non-commercial source for chemical lookups
* NIST Chemistry WebBook [2] is a freely available resource compiled by National Institute of Standards and Technology under the Standard Reference Data Program. Apart from chemical structures, it contains a wealth of associated physico-chemical information such as thermochemistry data and spectra
* ChEBI [3], a freely available dictionary of molecular entities focused on ‘small’ chemical compounds
* PubChem [4], maintained by the National Center for Biotechnology Information (NCBI), serves as a repository of chemical compounds from many public and commercial resources
* http://physchem.ox.ac.uk/MSDS/ Material Safety Data Sheets, plus other relevant links
These (commercial) links may also provide useful information:
* Chemfinder [5] is helpful for finding information about a chemical (disable and delete cookies!)
* Sigma Aldrich [6]
* Acros Organics [7]
* Lancaster [8]
* Chemical Suppliers Directory [9]
* ChemSpider [10]has over 20 million structures with chemical names and the ability to download the molfile locally. It includes links to chemical vendors, PubChem, ChEBI and over 100 other sources and is curated by users.
Whilst most compounds are referred to by their IUPAC name, "traditional" names have also been kept where they are in wide use or of significant historical interest.
See also: organic compound, list of compounds, list of inorganic compounds, inorganic compounds by element, list of biomolecules, polyatomic ions, list of elements by name, list of alchemical substances, list of drugs, list of reactions.
Table of contents: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
[edit] A
For substances with an A- or α- prefix such as α-Terpinene, please see the parent page (in this case Terpinene).
* Abietic acid - C20H30O2
* Acenaphthene
* Acenaphthoquinone
* Acenaphthylene
* Acepromazine
* Acetaldehyde — CH3CHO, also known as ethanal
* Acetamide
* Acetaminophen — C8H9NO2
* Acetaminosalol
* Acetamiprid
* Acetanilide
* Acetic acid — CH3COOH, also known as ethanoic acid, Glacial acetic acid or GAA
* Acetoguanamine
* Acetone — CH3COCH3, or (CH3)2CO
* Acetonitrile
* Acetophenone
* Acetylcholine – (CH3)3N+CH2CH2OCOCH3.
* Acetylene — C2H2
* N-Acetylglutamate
* Acetylsalicylic Acid also known as Aspirin
* Acid fuchsin
* Acridine — C13H9N
* Acridine orange
* Acrolein
* Acrylamide — C3H5NO
* Acrylic acid — CH2=CHCOOH
* Acrylonitrile
* Acryloyl chloride
* Acyclovir
* Adamantane
* Adenosine
* Adipamide
* Adipic acid
* Adiponitrile
* Adipoyl dichloride
* Adonitol
* Adrenaline, epinephrine
* Adrenochrome
* Aflatoxin
* Alanine
* Albumins
* Alcian blue
* Aldosterone
* Aldrin
* Aliquat 336
* Alizarin
* Allantoic acid
* Allantoin
* Allethrin
* Allyl propyl disulfide
* Allylamine
* Allyl chloride
* Amido black 10b
* p-Aminobenzoic acid (PABA)
* Aminodiacetic acid
* Aminoethylpiperazine
* 5-Amino-2-hydroxybenzoic acid
* Aminophylline
* 5-Aminosalicylic acid
* Aminothiazole
* Amiodarone
* Amiton
* Amobarbital
* Amoxicillin — C16H19N3O5S.3H2O
* Amphetamine
* Amyl nitrate
* Amyl nitrite — C5H11A.ONO
* Anethole
* Angelic acid
* Anilazine
* Aniline — C6H5-NH2
* Aniline hydrochloride
* Anisole
* Anisoyl chloride
* Anthanthrene
* Anthracene – (C6H4CH)2
* Anthramine
* Anthranilic acid
* Anthraquinone
* Anthrone
* Antipyrine
* Aprotinin
* Arabinose
* Arginine
* Aroclor (polychlorinated biphenyls)
* Ascorbic acid (vitamin C)
* Asparagine
* Asparagusic acid
* Aspartame
* Aspartic acid
* Asphidophytidine
* Astrablue
* Atrazine
* Auramine o
* Aureine
* Avobenzone
* Azadirachtin A — C35H44O16
* Azathioprine
* Azelaic acid
* Azinphos-methyl
* Aziridine
* Azithromycin
* Azo violet
* Azobenzene
* Azulene
* Azure a
[edit] B
For substances with a B- or β- prefix such as β-Pinene, please see the parent page (in this case Pinene).
* Bacillomycin
* Barbital
* Barbituric acid
* Behenic acid
* Benomyl
* Benzaldehyde
* Benzalkonium chloride
* Benzamide
* Benzanthrone
* Benzene — C6H6
* Benzethonium chloride
* Benzidine
* Benzil
* Benzilic acid
* Benzimidazole
* Benzisothiazolinone
* Benzisoxazole
* Benzo(a)anthracene
* Benzo(c)cinnoline
* Benzo(a)pyrene
* Benzo(c)phenanthrene
* Benzo(e)fluoranthene
* Benzo(e)pyrene
* Benzo(ghi)perylene
* Benzo(j)fluoranthene
* Benzo(k)fluoranthene
* Benzo(c)thiophene
* Benzocaine
* Benzofuran
* Benzoic acid
* Benzoin
* Benzothiazole
* Benzothiophene
* Benzotriazole
* Benzoxazole
* Benzoyl chloride
* Benzyl alcohol
* Benzyl chloroformate
* Benzylamine
* Benzyldimethylamine
* Benzylidene acetone
* Betaine
* Betulin
* Butylated hydroxytoluene (BHT) – C6H2(OH)(CH3)(C(CH3)3)2
* Biotin (Vitamin H)
* Biphenyl
* 2,2'-Bipyridyl = 2,2'-Bipyridine
* 1,8-Bis(dimethylamino)naphthalene (Proton-sponge, Aldrich trademark name)
* Bis(chloromethyl) ether
* Bismarck brown y
* Bisphenol A
* Biuret
* Borneol
* Brassinolide
* Brilliant cresyl blue
* Bromacil
* Bromoacetic acid
* Bromobenzene
* 2-Bromo-1-chloropropane
* Bromocresol purple
* Bromocyclohexane
* Bromoform
* Bromomethane — BrCH3
* Bromophenol blue
* 2-Bromopropane
* Bromothymol blue
* Bromotrifluoromethane
* Brucine
* Buckminsterfullerene
* Buspirone
* 1,3-Butadiene
* Butadiene resin
* Butane — C4H10
* Butene
* 2-Butoxyethanol
* Butylamine = n-Butylamine
* Butyllithium
* 2-Butyne-1,4-diol
* Butyraldehyde
* Butyrophenone
* Butyryl chloride
[edit] C
For substances with an c- or cis- prefix such as cis-3-hexenal, you may find these listed under the parent name letter (in this case "H"), as is the norm in chemical catalogues.
* Cacodylic acid
* Cacotheline
* Cadaverine — NH2(CH2)5NH2
* Cadinene
* Cafestol
* Caffeine
* Calcein
* Calciferol (Vitamin D)
* Calcitonin
* Calmodulin
* Calreticulin
* Camphene
* Camphor
* Cannabinol
* Caprolactam
* Caprolactone
* Capsaicin
* Captan
* Captopril
* Carbazole
* Carbazol-9-yl-methanol (N-(Hydroxymethyl)carbazole)
* Carbofuran
* Carbonyl fluoride
* Carboplatin
* Carboxypolymethylene
* Carminic acid
* Carnauba wax
* Carnitine
* Cartap
* Carvacrol
* Carvone
* Castor oil
* Catechol
* Cedar wood oil
* Cefazolin
* Cefotaxime
* Ceftriaxone
* Cellulose
* Cellulose acetate
* Cetrimide
* Cetyl alcohol
* Chloracetyl chloride
* Chloral
* Chloral hydrate
* Chlorambucil
* Chloramine-T
* Chloramphenicol
* Chloranilic acid
* Chlordane
* Chlorhexidine gluconate
* Chloro-m-cresol
* Chloroacetic acid
* 4-Chloroaniline (p-Chloroaniline)
* Chlorobenzene
* 2-Chlorobenzoic acid (o-Chlorobenzoic acid)
* Chlorodifluoromethane
* Chloroethene — C2H3Cl
* Chlorofluoromethane
* Chloroform — CHCl3
* Chloromethane
* 2-Chloro-2-methylpropane (tert butyl chloride)
* Chloronitroaniline
* Chloropentafluoroethane
* Chloropicrin
* Chloroprene
* Chloroquine
* Chlorostyrene
* Chlorothiazide
* Chlorotrifluoromethane
* Chlorotrimethylsilane
* Chloroxuron
* Chlorpyrifos
* Chlorthiamide
* Cholesterol
* Choline
* Chromotropic acid
* Cilostazol
* Cinchonine
* Cinnamaldehyde
* Cinnamic acid
* Cinnamyl alcohol
* Cinnoline — C4H4N2
* cis-2-butene
* cis-3-Hexenal
* cis-3-Hexen-1-ol
* Citral
* Citric acid — C3H4OH(COOH)3
* Citronella oil
* Citronellal
* Citrulline
* Clobetasone
* Clopidol
* Cloxacillin — C19H17ClN3O5S*Na*H2O
* Cobalamin (Vitamin B12)
* Cocamidopropyl
* Colchicine
* Collagen
* Collodion
* Congo red
* Coniine
* Coomassie blue
* Coronene
* Coumarin
* Creatine
* Cresol
* Cresyl violet
* Crotonaldehyde
* 18-Crown-6
* Crystal violet
* Cubane
* Cumene
* Cuneane
* Cupferron
* Cuscohygrine
* Cyanogen
* Cyanogen chloride
* Cyanoguanidine
* Cyanuric acid
* Cyanuric chloride
* Cyclodecane
* α-Cyclodextrin
* Cyclododecane
* Cycloheptatriene
* 1,3-Cyclohexadiene
* 1,4-Cyclohexadiene
* Cyclohexane
* Cyclohexanol
* Cyclohexanone
* Cyclohexene
* Cyclonite - (CH2-N-NO2)3
* Cyclooctatetraene
* Cyclopentadiene — C5H6
* Cyclopentane
* Cyclopentanol
* Cyclopentanone
* Cyclopentene
* Cypermethrin
* Cysteamine
* Cysteine
* Cystine
* Cytosine — C4H5N3O
[edit] D
For substances with a d- or D- prefix such as D-alanine or DL-alanine, please see the parent page (in this case alanine).
* DABCO
* DDT
* Decaborane
* Decabromodiphenyl ether
* Decahydronaphthalene
* Decane — C10H22
* Dehydroacetic acid
* Dehydrocholic acid
* Deltamethrin
* Demeton
* Denatonium
* Dexamethazone
* Dextran
* Dextrin
* 3,3'-Diaminobenzidine
* Di-t-butyl peroxide
* Diacetylene
* Diazinon
* Diazomethane
* 1,2-Dibromoethane
* Dibucaine hydrochloride
* Dichloroacetic acid
* p-Dichlorobenzene
* Dichlorobutane
* Dichlorodifluoromethane
* Dichlorodimethylsilane
* 1,2-Dichloroethane
* Dichlorofluoromethane
* Dichlorophen
* 2,4-Dichlorophenoxyacetic acid
* Dichlorotrifluoroethane
* Dichlorvos
* Diclofenac sodium
* Dicofol
* Dicrotophos
* Dicyclopentadiene
* Dieldrin
* Diethanolamine
* Diethion
* Diethyl aluminium chloride a Lewis acid
* Diethylamine
* Diethylene glycol
* Diethylenetriamine
* Diethyl ether
* Difluoromethane
* Digitonin
* Dihydrocortisone
* Diisoheptyl phthalate
* Diisopropyl ether
* Diketene
* Dimethicone
* Dimethylamine
* N,N-Dimethylacetamide
* N,N-dimethylaniline
* 1,2-Dimethylbenzene (o-Xylene)
* 1,3-Dimethylbenzene (m-Xylene)
* 1,4-Dimethylbenzene (p-Xylene)
* N,N-dimethylformamide
* Dimethyldiethoxysilane
* Dimethylglyoxime
* Dimethylmercury
* Dimethyl sulfoxide
* Dinoseb
* Dioctyl phthalate
* Dioxane
* Dioxathion
* Dioxin
* Diphenylacetylene (Tolane)
* Diphenylmethanol (Benzhydrol)
* Diquat
* Direct Blue 1
* Disulfiram
* Disulfoton
* Dithranol
* 2,6-Di-tert-butylphenol
* 2,6-Di-tert-butyl-4-methylphenol
* 2,6-Di-tert-butylpyridine
* Diuron
* Divinylbenzene
* Docosane
* Dodecane
* Dodecylbenzene
* Domperidone
* Dopamine
* Doxylamine succinate
[edit] E
* EDTA (Ethylenediamine-N,N,N',N'-tetraacetic acid)
* Eicosane
* Endosulfan
* Endrin
* Eosin
* Ephedrine
* Epibromohydrin
* Epinephrine — C9H13NO3
* Erucic acid — CH3(CH2)7CH=CH(CH2)11COOH
* Erythritol
* Estradiol
* Ethacridine lactate
* Ethane — C2H6
* 1,2-Ethanedithiol — C2H4(SH2)2
* Ethanol — CH3CH2OH
* Ethene — C2H4
* Ethidium bromide
* Ethyl acetate
* Ethylamine
* Ethyl 4-aminobenzoate (Ethyl p-aminobenzoate)
* Ethylbenzene
* Ethyl chloride
* Ethylene
* Ethylene glycol — OHCH2CH2OH
* Ethylene oxide
* Ethyl formate
* 2-Ethyl-1-hexanol
* Eugenol
[edit] F
* Farnesol
* Ferrocene
* Fipronil
* Flunixin
* Fluoranthene
* Fluorene
* 9-Fluorenone
* Fluorescein
* Fluorobenzene
* Fluoroethylene
* Fluoxetine
* Folic acid (Vitamin M)
* Fonofos
* Formaldehyde — HCHO
* Formamide
* Formanilide
* Formic acid — HCOOH
* Formoterol
* Fructose
* Fumaric acid
* Furan (furane)
* Furfural
* Furfuryl alcohol
* Furfurylamine
* Furylfuramide
[edit] G
* Gadopentetate - also known as Magnevist
* Galactose
* Gamma-aminobutyric acid
* Gamma-butyrolactone
* Gamma-hydroxybutyrate (GHB)
* Geraniol
* Gibberellic acid
* Gluconic acid
* Glucose — C6H12O6
* Glutamic acid (glutamate)
* Glutamine
* Glutaraldehyde
* Glutaric acid
* Glutathione
* Glyburide
* Glycerin (glycerol)
* Glycerol (glycerin)
* Glycerophosphoric acid
* Glycidol
* Glycine — NH2CH2COOH
* Glycogen
* Glycolic acid
* Glyoxal
* Guaiacol
* Guanidine
* Guanine
* Guanosine
[edit] H
* Halothane
* Hematoxylin
* HEPES
* Heptadecane
* Heptane — C7H16
* Hexabromocyclododecane
* Hexachloropropene
* Hexadecane
* Hexafluoro-2-propanol
* Hexafluoro-2-propanone
* Hexafluoroethane
* Hexafluoropropylene
* Hexamethyldewarbenzene
* Hexamethyldisilazane
* Hexamethylenimine
* Hexamethylolmelamine
* Hexamine – (CH2)6N4
* Hexane — C6H14
* Hexanitrodiphenylamine
* Hexanoic acid
* cis-3-Hexanal
* cis-3-Hexen-1-ol
* Hippuric acid
* Histidine — NH2CH(C4H5N2)COOH
* Histamine
* Homoarginine
* Homocysteine
* Homocystine
* Homotaurine
* Hydrochlorothiazide
* Hydrocinnamic acid
* Hydroquinone
* Hydroxyproline
* 5-Hydroxytryptamine
* Hygrine
[edit] I
* Ibuprofen
* Imazapyr
* Imidazole
* Imiquimod
* Indazole
* Indene
* Indigo
* Indole
* Indoline
* Indole-3-acetic acid
* Inositol
* Iodoxybenzene
* Ionone
* Ipratropium bromide
* Isatin
* Isoamyl isobutyrate
* Isobenzofuran
* Isoborneol
* Isobornyl acetate
* Isoflurane
* Isoindole
* Isoleucine
* Isomelamine
* Isooctanol
* Isophthalic acid
* Isopropanol – (CH3)2CHOH, also known as IPA, IsoPropyl alcohol
* Isoquinoline
* Isoxazole
* Itraconazole
[edit] J
* Jasmone
* Jenner's stain
[edit] K
* Kanamycin
* Kepone alcohol
* Keratin
* Ketene
* Kojic acid
[edit] L
For substances with an l- or L- prefix such as L-alanine or DL-alanine, please see the parent page (in this case alanine).
* Lactic acid — CH3CH(OH)COOH
* Lactose
* Lauric acid
* Lauryl alcohol
* LDA (Lithium diisopropylamide)
* Leucine
* Levulinic acid
* Limonene
* Linalool
* Linoleic acid
* Linolenic acid
* Lipoamide
* Lithium diisopropylamide
* Loratadine
* LSD
* Luminol
* 2,6-Lutidine
* Lycopene
* Lysine
[edit] M
For substances with an m- or meta- prefix such as m-cresol, meta-cresol or metacresol that are not listed below, please look for a more generic page (in this case cresol). For substances with a meso- prefix such as meso-tartaric acid or mesotartaric acid that are not listed below, please see the parent page (in this case tartaric acid).
* Malachite green
* Malathion
* Maleic anhydride
* Malic acid
* Maltose
* Mandelonitrile
* Mannide monooleate
* Mannose
* Mauveine
* MDMA
* Mecoprop
* MEK
* Melatonin
* Meldola's blue
* Meloxicam
* Menthol
* 2-Mercaptoethanol
* 2-Mercaptopyridine
* Merocyanine
* Mesityl oxide
* Mesitylene – (CH3)3-C6H3
* Mesotartaric acid
* Metaldehyde
* Metamizole (dipyrone)
* Methane — CH4
* Methanesulfonic acid
* Methanol — CH3OH
* Methionine
* Methomyl
* 4-Methoxybenzaldehyde (anisaldehyde)
* Methoxychlor
* Methoxyflurane
* Methyl acetate
* Methyl-2-cyanoacrylate
* Methyl ethyl ketone (MEK)
* Methyl isobutyl ketone (MIBK)
* Methyl isocyanate — CH3-N=C=O
* Methyl methacrylate
* Methyl tert-butyl ether (MTBE)
* Methylal
* Methylamine
* 2-Methylbenzoic acid (o-Toluic acid)
* 4-Methylbenzoic acid (p-Toluic acid)
* Methyl chloroformate
* Methylcyclohexane
* Methylene blue — C16H18ClN3S
* Methylhydrazine
* Methylmercury
* Methylmorpholine
* 2-Methylpropene (isobutylene)
* N-Methylpyrrolidone — C5H9NO
* Methyltriethoxysilane
* Methyltrimethoxysilane
* Metoprolol
* Metronidazole
* Michler's ketone
* Milrinone
* Monocrotophos
* Monosodium glutamate
* Mordant red 19
* Morpholine
* MTBE
* Murexide
* Mustard gas — C4H8Cl2S
* Myrcene
[edit] N
For substances with an n- or normal- prefix such as n-pentane that are not listed below, please see the parent page (in this case pentane).
For substances with an N- prefix (meaning on nitrogen) such as N,N-dimethylformamide, if these are not listed below please see the parent page (in this case dimethylformamide).
* n-Nonadecane
* n-Tetradecylbenzene
* Naphthalene — C10H8
* Naphthoquinone (Vitamin K)
* 2-Naphthylamine
* Neomycin
* Niacin or nicotinic acid (Vitamin B3)
* Nicotine
* Niflumic acid
* Nile red
* Nimesulide
* Nitrilotriacetic acid
* Nitrobenzene
* Nitrocellulose
* Nitroethane
* Nitrofen
* Nitrofurantoin
* Nitroglycerine — C3H5(NO2)3
* Nitromethane
* Nitrosobenzene
* N-Nitroso-N-methylurea
* Nitrosomethylurethane
* Nominine
* Nonacosane
* Nonane — C9H20
* Noradrenaline, norepinephrine
* Norephidrine
* Norcarane
* Norleucine
* Nujol
* NMN
[edit] O
For substances with an o- or ortho- prefix such as o-cresol, ortho-cresol or orthocresol that are not listed below, please look for a more generic page (in this case cresol).
* Octabromodiphenyl ether
* Octane — C8H18
* 1-Octanethiol
* Octanoic acid
* 4-Octylphenol
* Oleic acid
* Orcin
* Orcinol
* Ornithine
* Orotic acid
* Oxalic acid
* Oxalyl Chloride — C2O2Cl2
* Oxamide
* Oxazole
* Oxolinic acid
* Oxymetholone
[edit] P
For substances with an p- or para- prefix such as p-cresol, para-cresol or paracresol that are not listed below, please look for a more generic page (in this case cresol).
* p-nitro benzal dehyde
* PABA
* Paclitaxel
* Palmitic acid
* Pantothenic acid (Vitamin B5)
* Para red
* Parachlorometaxylenol (PCMX)
* Paraformaldehyde
* Parathion
* Pelargonic acid
* Pentabromodiphenyl ether
* Pentachlorobiphenyl
* Pentachlorophenol
* Pentadecane
* Pentaerythritol
* Pentaethylene glycol
* Pentafluoroethane
* Pentane — C5H12
* Pentetic acid
* Perfluorotributylamine
* Permethrin
* Peroxyacetic acid
* Perylene
* Petroleum ether
* Phenacetin
* Phenacyl bromide
* Phenanthrene
* Phenanthrenequinone
* Phencyclidine
* Phenethylamine
* Phenobarbital (c-iv)
* Phenol — C6H5OH
* Phenol red, sodium salt
* Phenolphthalein
* Phenothiazine
* Phenylacetic acid
* Phenylacetylene
* Phenylalanine
* p-Phenylenediamine
* Phenylhydrazine
* Phenylhydroxylamine
* Phenyllithium
* 4-Phenyl-4-(1-piperidinyl)cyclohexanol (PPC)
* Phenylthiocarbamide — C7H8N2S
* Phloroglucinol
* Phorate
* Phthalic anhydride
* Phthalic acid
* Phytic acid
* 4-Picoline
* Picric acid — C6H2(OH)(NO2)3
* Pimelic acid
* Pinacol
* Piperazine
* Piperidine
* Piperonal
* Piperylene
* Pivaloyl chloride
* Polyacrylonitrile
* Polyamide 6 = Nylon 6
* Polybenzimidazole - Polybenzimidazole fiber
* Polyethylenimine
* Polygeline
* Polyisobutylene
* Polypropylene
* Polypropylene glycol
* Polystyrene
* Polyurethane
* Polyvinyl acetate
* Polyvinyl alcohol
* Polyvinyl chloride
* Polyvinylidene chloride
* Polyvinylidene fluoride (PVDF)
* Polyvinylpyrrolidone = Poly vinyl pyrrolidone (PVP)
* Porphyrin
* Potassium clavulanate — C8H8KNO5
* Potassium 2-ethyl hexanoate — C8H15KO2
* Prednisone
* Primaquine
* Procaine
* Progesterone
* Prolactin (PRL)
* Proline
* Propane — C3H8
* Propanoic acid
* 2-Propanone
* Propargyl alcohol
* Propiconazole
* Propiolactone
* Propiolic acid
* Propionaldehyde
* Propionitrile
* Propoxur
* Proton-sponge (Aldrich trademark name)
* Purine
* Putrescine — C4H12N2
* Pyrazine
* Pyrazole
* Pyrene
* Pyrethrin
* Pyridazine
* Pyridine — C5H5N
* Pyridinium tribromide
* 2-Pyridone
* Pyridoxal
* Pyridoxine or pyridoxamine (Vitamin B6)
* Pyrilamine
* Pyrimethamine
* Pyrimidine — C4H4N2
* Pyrocatechol violet
* Pyroglutamic acid
* Pyrrole
* Pyrrolidine
* Pyruvic acid
[edit] Q
* Quinaldine
* Quinazoline
* Quinhydrone
* Quinoline
* Quinone
* Quinoxaline
[edit] R
* Raffinose
* Resorcinol
* Retinene
* Retinol (Vitamin A)
* Rhodanine
* Riboflavin (vitamin B2)
* Ribofuranose
* Ribose
* Ricin
* Rosolic acid
* Rotane
* Rotenone
[edit] S
For substances with an s- or secondary- prefix such as s-butyllithium or sec-butyllithium that are not listed below, please see the parent page (in this case under B, butyllithium).
* Saccharin
* Safrole
* Salicin
* Salicylaldehyde
* Salicylic acid
* Salvinorin A
* Sarin
* Sclareol
* Sebacic acid
* Sebacoyl chloride
* Selacholeic acid
* Selenocysteine
* Selenomethionine
* Serine
* Serine kinase
* Serotonin
* Shikimic acid
* Sildenafil (also known as Viagra)
* Skatole
* Snakeroot oil
* Sorbic acid
* Sotolone
* Spermidine
* Squalene
* Stearic acid
* Strychnine
* Styrene
* Succinic anhydride
* Sucrose (sugar)
* Sulfanilamide
* Sulfanilic acid
* Sulforhodamine b
* Suxamethonium chloride
[edit] T
For substances with an t- or tertiary- prefix such as t-butyllithium or tert-butyllithium that are not listed below, please see the parent page (in this case under B, butyllithium). For substances with an t- or trans- prefix such as *trans-2-Butene, you may find these listed under the parent name letter (in this case "B"), as is the norm in chemical catalogues.
* Tabun — C2H5OP(O)(CN)N(CH3)2
* Tannic acid
* Tannin
* Tartaric acid
* Tartrazine
* Taurine
* Terephthalic acid
* Terephthalonitrile
* p-Terphenyl
* α-Terpineol
* Testosterone
* Tetrachlorobiphenyl
* Tetrachloroethylene
* Tetrachloromethane (carbon tetrachloride) – CCl4
* Tetradecane
* Tetraethylene glycol
* Tetrafluoroethene
* Tetrahedrane
* Tetrahydrofuran
* Tetrahydronaphthalene
* Tetramethrin
* Tetramethylsilane (TMS, standard for NMR)
* Tetramethylurea
* Tetranitromethane
* Tetrathiafulvalene (TTF)
* Tetrazine — C2H2N4 (hypothetical)
* Tetrodotoxin
* Tetryl — C7H5N5O8
* Thalidomide
* Thiamine (Vitamin B1) – C12H17ClN4OS·HCl
* Thiazole
* Thioacetamide
* Thiolactic acid
* Thiophene
* Thiophosgene
* Thiourea
* Thiram
* Thorin
* Threonine
* Thrombopoietin
* Thymidine
* Thymine
* Thymol
* Thymolphthalein
* Thyroxine (T4)
* Tiglic acid
* Tinidazole
* Tocopherol (Vitamin E)
* Toluene — C6H5CH3
* Toluene diisocyanate
* p-Toluenesulfonic acid
* o-Toluic acid (2-Methylbenzoic acid)
* p-Toluic acid (4-Methylbenzoic acid)
* Toxaphene
* Triangulane
* Triazole
* Tributyl phosphate
* Tributylamine
* Tributylphosphine
* Trichloroacetic acid
* Trichloroacetonitrile
* 1,1,1-Trichloroethane
* Trichloroethylene
* Trichlorofluoromethane
* 2,4,6-Trichloroanisole
* 2,4,6-Trichlorophenol
* Tris
* Tricine
* Triclabendazole
* Triclosan
* Tricosane
* Tridecane
* Tridecanoic acid
* Triethylaluminium
* Triethylamine
* Triethylamine hydrochloride — C6H15N·HCl
* Triethylene glycol
* Triethylenediamine
* Trifluoroacetic acid (TFA)
* 1,1,1-Trifluoroethane
* 2,2,2-Trifluoroethanol
* Trifluoromethane
* Trimellitic anhydride
* Trimethoxyamphetamine
* Trimethyl phosphite
* Trimethylamine
* Trimethylbenzene
* 2,2,4-Trimethylpentane (isooctane)
* Trinitrotoluene (TNT) – C6H2(NO2)3CH3 or 2,4,6-trinitrotoluene
* Tri-o-cresyl phosphate
* Triphenyl phosphate
* Triphenylamine
* Triphenylantimony
* Triphenylene
* Triphenylmethane
* Triphenylmethanol
* Triphenylphosphine
* Tropane
* Tropinone
* Trypan blue
* Tryptophan
* Tyrosine — C9O3H11N
[edit] U
* Umbelliferone
* Undecanol
* Uracil
* Urea — CO(NH2)2
* Urethane
* Uric acid — C5H4N4O3
* Uridine
* Usnic acid
[edit] V
* Valine
* Valium
* Valproic acid
* Vanillin
* Venlafaxine
* Vigulariol
* Vinyl acetate
* Vinyl fluoride
* Vinylidene chloride
* Violanthrone-79 (16,17-bis(octyloxy)anthra[9,1,2-cde]benzo[rst]pentaphene-5,10-dione)
* Vitamin A (retinol)
* Vitamin B
* Vitamin B1 (thiamine)
* Vitamin B2 (riboflavin)
* Vitamin B3 (niacin or nicotinic acid)
* Vitamin B4 (adenine)
* Vitamin B5 (pantothenic acid)
* Vitamin B6 (pyridoxine or pyridoxamine)
* Vitamin B12 (cobalamin)
* Vitamin C (ascorbic acid)
* Vitamin D (calciferol)
* Vitamin E (tocopherol)
* Vitamin F
* Vitamin H (biotin)
* Vitamin K (naphthoquinone)
* Vitamin M (folic acid)
* Vitamin P (niacin or nicotinic acid)
* Vitamin S
[edit] W
* Warfarin
[edit] X
* Xanthan gum
* Xanthone
* Xylene
* Xylene cyanole ff
* Xylenol orange
* Xylose
* Xylyl bromide
[edit] Y
* Yohimbine hydrochloride - C21H26N2O3
* Yohimbinic acid monohydrate
[edit] Z
* Zingiberene
Sunday, October 12, 2008
"ABOUT ACID"
Acid
From Wikipedia, the free encyclopedia
(Redirected from Acids)
Jump to: navigation, search
For other uses, see Acid (disambiguation).
This article is about acids in chemistry. For the drug, see Lysergic acid diethylamide.
"Acidity" redirects here. For the novelette, see Acidity (Novelette).
Acids and bases:
* Acid dissociation constant
* Acid-base extraction
* Acid-base reaction
* Acid-base physiology
* Acid-base homeostasis
* Dissociation constant
* Acidity function
* Buffer solutions
* pH
* Proton affinity
* Self-ionization of water
* Acids:
o Lewis acids
o Mineral acids
o Organic acids
o Strong acids
o Superacids
o Weak acids
* Bases:
o Lewis bases
o Organic bases
o Strong bases
o Superbases
o Non-nucleophilic bases
o Weak bases
edit
An acid (often represented by the generic formula HA [H+A-]) is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity greater than in pure water, i.e. a pH less than 7.0. That approximates the modern definition of Johannes Nicolaus Brønsted and Martin Lowry, who independently defined an acid as a compound which donates a hydrogen ion (H+) to another compound (called a base). Common examples include acetic acid (in vinegar) and sulfuric acid (used in car batteries). Acid/base systems are different from redox reactions in that there is no change in oxidation state.
Contents
[hide]
* 1 Definitions
* 2 Properties
* 3 Nomenclature
* 4 Chemical characteristics
o 4.1 Monoprotic acids
o 4.2 Polyprotic acids
o 4.3 Neutralization
o 4.4 Weak acid/weak base equilibria
* 5 Applications of acids
* 6 Biological occurrence
* 7 Common acids
o 7.1 Mineral acids
o 7.2 Sulfonic acids
o 7.3 Carboxylic acids
o 7.4 Vinylogous carboxylic acids
* 8 References
* 9 See also
* 10 External links
[edit] Definitions
Main article: acid-base reaction theories
The word "acid" comes from the Latin acidus meaning "sour," but in chemistry the term acid has a more specific meaning. There are four common ways to define an acid:
* Arrhenius: According to this definition developed by the Swedish chemist Svante Arrhenius, an acid is a substance that increases the concentration of hydrogen ions (H+), which are carried as hydronium ions (H3O+) when dissolved in water, while bases are substances that increase the concentration of hydroxide ions (OH-). This definition limits acids and bases to substances that can dissolve in water. Around 1800, many French chemists, including Antoine Lavoisier, incorrectly believed that all acids contained oxygen. Indeed the modern German word for oxygen is Sauerstoff (lit. sour substance), as is the Afrikaans word for oxygen suurstof, with the same meaning. English chemists, including Sir Humphry Davy, at the same time believed all acids contained hydrogen. Arrhenius used this belief to develop this definition of acid.
* Brønsted-Lowry: According to this definition, an acid is a proton (hydrogen nucleus) donor and a base is a proton acceptor. The acid is said to be dissociated after the proton is donated. An acid and the corresponding base are referred to as conjugate acid-base pairs. Brønsted and Lowry independently formulated this definition, which includes water-insoluble substances not in the Arrhenius definition. Acids according to this definition are variously referred to as Brønsted acids, Brønsted-Lowry acids, proton acids, protic acids, or protonic acids.
* Solvent-system definition: According to this definition, an acid is a substance that, when dissolved in an autodissociating solvent, increases the concentration of the solvonium cations, such as H3O+ in water, NH4+ in liquid ammonia, NO+ in liquid N2O4, SbCl2+ in SbCl3, etc. Base is defined as the substance that increases the concentration of the solvate anions, respectively OH-, NH2-, NO3-, or SbCl4-. This definition extends acid-base reactions to non-aqueous systems and even some aprotic systems, where no hydrogen nuclei are involved in the reactions. This definition is not absolute, a compound acting as acid in one solvent may act as a base in another.
* Lewis: According to this definition developed by Gilbert N. Lewis, an acid is an electron-pair acceptor and a base is an electron-pair donor. (These are frequently referred to as "Lewis acids" and "Lewis bases," and are electrophiles and nucleophiles, respectively, in organic chemistry; Lewis bases are also ligands in coordination chemistry.) Lewis acids include substances with no transferable protons (ie H+ hydrogen ions), such as iron(III) chloride, and hence the Lewis definition of an acid has wider application than the Brønsted-Lowry definition. In fact, the term Lewis acid is often used to exclude protic (Brønsted-Lowry) acids. The Lewis definition can also be explained with molecular orbital theory. In general, an acid can receive an electron pair in its lowest unoccupied orbital (LUMO) from the highest occupied orbital (HOMO) of a base. That is, the HOMO from the base and the LUMO from the acid combine to a bonding molecular orbital.
Although not the most general theory, the Brønsted-Lowry definition is the most widely used definition. The strength of an acid may be understood by this definition by the stability of hydronium and the solvated conjugate base upon dissociation. Increasing or decreasing stability of the conjugate base will increase or decrease the acidity of a compound. This concept of acidity is used frequently for organic acids such as carboxylic acid. The molecular orbital description, where the unfilled proton orbital overlaps with a lone pair, is connected to the Lewis definition.
[edit] Properties
Bronsted-Lowry acids:
* Are generally sour in taste
* Strong or concentrated acids often produce a stinging feeling on mucous membranes
* Change the color of pH indicators as follows: turn blue litmus and methyl orange red, turn phenolphthalein colorless
* React with metals to produce a metal salt and hydrogen
* React with metal carbonates to produce water, CO2 and a salt
* React with a base to produce a salt and water
* React with a metal oxide to produce water and a salt
* Conduct electricity, depending on the degree of dissociation
* Produce solvonium ions, such as hydronium (H3O+) ions in water
Acids can be gases, liquids, or solids. Respective examples (at 20 °C and 1 atm) are hydrogen chloride, sulfuric acid and citric acid. Solutions of acids in water are liquids, such as hydrochloric acid - an aqueous solution of hydrogen chloride. At 20 °C and 1 atm, linear carboxylic acids are liquids up to nonanoic acid (nine carbon atoms) and solids beginning from decanoic acid (ten carbon atoms). Aromatic carboxylic acids, the simplest being benzoic acid, are solids.
Strong acids and many concentrated acids, being corrosive, can be dangerous; causing severe burns for even minor contact. Generally, acid burns on the skin are treated by rinsing the affected area abundantly with running water, followed up with immediate medical attention. In the case of highly concentrated mineral acids such as sulfuric acid or nitric acid, the acid should first be wiped off, otherwise the exothermic mixing of the acid and the water could cause thermal burns.[citation needed] Particular acids may also be dangerous for reasons not related to their acidity. Material Safety Data Sheets (MSDS) can be consulted for detailed information on dangers and handling instructions.
[edit] Nomenclature
In the classical naming system, acids are named according to their anions. That ionic suffix is dropped and replaced with a new suffix (and sometimes prefix), according to the table below. For example, HCl has chloride as its anion, so the -ide suffix makes it take the form hydrochloric acid. In the IUPAC naming system, "aqueous" is simply added to the name of the ionic compound. Thus, for hydrogen chloride, the IUPAC name would be aqueous hydrogen chloride.
Classical naming system:
Anion Prefix Anion Suffix Acid Prefix Acid Suffix Example
per ate per ic acid perchloric acid (HClO4)
ate ic acid chloric acid (HClO3)
ite ous acid chlorous acid (HClO2)
hypo ite hypo ous acid hypochlorous acid (HClO)
ide hydro ic acid hydrochloric acid (HCl)
[edit] Chemical characteristics
In water the following equilibrium occurs between a weak acid (HA) and water, which acts as a base:
HA(aq) + H2O ⇌ H3O+(aq) + A-(aq)
The acidity constant (or acid dissociation constant) is the equilibrium constant for the reaction of HA with water:
K_a = \frac{[\mbox{H}_3\mbox{O}^+][\mbox{A}^-]}{[\mbox{HA}]}
Strong acids have large Ka values (i.e. the reaction equilibrium lies far to the right; the acid is almost completely dissociated to H3O+ and A-). Strong acids include the heavier hydrohalic acids: hydrochloric acid (HCl), hydrobromic acid (HBr), and hydroiodic acid (HI). (However, hydrofluoric acid, HF, is relatively weak.) For example, the Ka value for hydrochloric acid (HCl) is 107.
Weak acids have small Ka values (i.e. at equilibrium significant amounts of HA and A− exist together in solution; modest levels of H3O+ are present; the acid is only partially dissociated). For example, the Ka value for acetic acid is 1.8 x 10-5. Most organic acids are weak acids. Oxoacids, which tend to contain central atoms in high oxidation states surrounded by oxygen may be quite strong or weak. Nitric acid, sulfuric acid, and perchloric acid are all strong acids, whereas nitrous acid, sulfurous acid and hypochlorous acid are all weak.
Note on terms used:
* The terms "hydrogen ion" and "proton" are used interchangeably; both refer to H+.
* In aqueous solution, the water is protonated to form hydronium ion, H3O+(aq). This is often abbreviated as H+(aq) even though the symbol is not chemically correct.
* The strength of an acid is measured by its acid dissociation constant (Ka) or equivalently its pKa (pKa= - log(Ka)).
* The pH of a solution is a measurement of the concentration of hydronium. This will depend on the concentration and nature of acids and bases in solution.
[edit] Monoprotic acids
Monoprotic acids are those acids that are able to donate one proton per molecule during the process of dissociation (sometimes called ionization) as shown below (symbolized by HA):
HA(aq) + H2O(l) ⇌ H3O+(aq) + A−(aq) Ka
Common examples of monoprotic acids in mineral acids include hydrochloric acid (HCl) and nitric acid (HNO3). On the other hand, for organic acids the term mainly indicates the presence of one carboxyl group and sometimes these acids are known as monocarboxylic acid. Examples in organic acids include formic acid (HCOOH), acetic acid (CH3COOH) and benzoic acid (C6H5COOH).
[edit] Polyprotic acids
Polyprotic acids are able to donate more than one proton per acid molecule, in contrast to monoprotic acids that only donate one proton per molecule. Specific types of polyprotic acids have more specific names, such as diprotic acid (two potential protons to donate) and triprotic acid (three potential protons to donate).
A diprotic acid (here symbolized by H2A) can undergo one or two dissociations depending on the pH. Each dissociation has its own dissociation constant, Ka1 and Ka2.
H2A(aq) + H2O(l) ⇌ H3O+(aq) + HA−(aq) Ka1
HA−(aq) + H2O(l) ⇌ H3O+(aq) + A2−(aq) Ka2
The first dissociation constant is typically greater than the second; i.e., Ka1 > Ka2 . For example, sulfuric acid (H2SO4) can donate one proton to form the bisulfate anion (HSO4−), for which Ka1 is very large; then it can donate a second proton to form the sulfate anion (SO42−), wherein the Ka2 is intermediate strength. The large Ka1 for the first dissociation makes sulfuric a strong acid. In a similar manner, the weak unstable carbonic acid (H2CO3) can lose one proton to form bicarbonate anion (HCO3−) and lose a second to form carbonate anion (CO32−). Both Ka values are small, but Ka1 > Ka2 .
A triprotic acid (H3A) can undergo one, two, or three dissociations and has three dissociation constants, where Ka1 > Ka2 > Ka3 .
H3A(aq) + H2O(l) ⇌ H3O+(aq) + H2A−(aq) Ka1
H2A−(aq) + H2O(l) ⇌ H3O+(aq) + HA2−(aq) Ka2
HA2−(aq) + H2O(l) ⇌ H3O+(aq) + A3−(aq) Ka3
An inorganic example of a triprotic acid is orthophosphoric acid (H3PO4), usually just called phosphoric acid. All three protons can be successively lost to yield H2PO4−, then HPO42−, and finally PO43− , the orthophosphate ion, usually just called phosphate. An organic example of a triprotic acid is citric acid, which can successively lose three protons to finally form the citrate ion. Even though the positions of the protons on the original molecule may be equivalent, the successive Ka values will differ since it is energetically less favorable to lose a proton if the conjugate base is more negatively charged.
[edit] Neutralization
Hydrochloric acid (in beaker) reacting with ammonia fumes to produce ammonium chloride (white smoke).
Hydrochloric acid (in beaker) reacting with ammonia fumes to produce ammonium chloride (white smoke).
Neutralization is the reaction between an acid and a base, producing a salt and neutralized base; for example, hydrochloric acid and sodium hydroxide form sodium chloride and water:
HCl(aq) + NaOH(aq) → H2O(l) + NaCl(aq)
Neutralization is the basis of titration, where a pH indicator shows equivalence point when the equivalent number of moles of a base have been added to an acid. It is often wrongly assumed that neutralization should result in a solution with pH 7.0, which is only the case with similar acid and base strengths during a reaction.
Neutralization with a base weaker than the acid results in a weakly acidic salt. An example is the weakly acidic ammonium chloride, which is produced from the strong acid hydrogen chloride and the weak base ammonia. Conversely, neutralizing a weak acid with a strong base gives a weakly basic salt, e.g. sodium fluoride from hydrogen fluoride and sodium hydroxide.
[edit] Weak acid/weak base equilibria
Main article: Henderson-Hasselbalch equation
In order to lose a proton, it is necessary that the pH of the system rise above the pKa of the protonated acid. The decreased concentration of H+ in that basic solution shifts the equilibrium towards the conjugate base form (the deprotonated form of the acid). In lower-pH (more acidic) solutions, there is a high enough H+ concentration in the solution to cause the acid to remain in its protonated form, or to protonate its conjugate base (the deprotonated form).
Solutions of weak acids and salts of their conjugate bases form buffer solutions.
[edit] Applications of acids
There are numerous uses for acids. Acids are often used to remove rust and other corrosion from metals in a process known as pickling. They may be used as an electrolyte in a wet cell battery, such as sulfuric acid in a car battery.
Strong acids, sulfuric acid in particular, are widely used in mineral processing. For example, phosphate minerals react with sulfuric acid to produce phosphoric acid for the production of phosphate fertilizers, and zinc is produced by dissolving zinc oxide into sulfuric acid, purifying the solution and electrowinning.
In the chemical industry, acids react in neutralization reactions to produce salts. For example, nitric acid reacts with ammonia to produce ammonium nitrate, a fertilizer. Additionally, carboxylic acids can be esterified with alcohols, to produce esters.
Acids are used as catalysts; for example, sulfuric acid is used in very large quantities in the alkylation process to produce gasoline. Strong acids, such as sulfuric, phosphoric and hydrochloric acids also effect dehydration and condensation reactions.
Acids are used as additives to drinks and foods, as they alter their taste and serve as preservatives. Phosphoric acid, for example, is component of cola drinks.
[edit] Biological occurrence
In humans and many other animals, hydrochloric acid is a part of the gastric acid secreted within the stomach to help hydrolyze proteins and polysaccharides, as well as converting the inactive pro-enzyme, pepsinogen into the enzyme, pepsin. Some organisms produce acids for defense; for example, ants produce formic acid.
[edit] Common acids
[edit] Mineral acids
* Solutions of hydrogen halides, such as hydrochloric acid (HCl) and hydrobromic acid (HBr)
* Sulfuric acid (H2SO4)
* Nitric acid (HNO3)
* Phosphoric acid (H3PO4)
* Chromic acid (H2CrO4)
[edit] Sulfonic acids
* Methanesulfonic acid (aka mesylic acid) (MeSO3H)
* Ethanesulfonic acid (aka esylic acid) (EtSO3H)
* Benzenesulfonic acid (aka besylic acid) (PhSO3H)
* Toluenesulfonic acid (aka tosylic acid, or (C6H4(CH3) (SO3H))
[edit] Carboxylic acids
* Formic acid
* Acetic acid
* Citric acid
[edit] Vinylogous carboxylic acids
* Ascorbic acid
From Wikipedia, the free encyclopedia
(Redirected from Acids)
Jump to: navigation, search
For other uses, see Acid (disambiguation).
This article is about acids in chemistry. For the drug, see Lysergic acid diethylamide.
"Acidity" redirects here. For the novelette, see Acidity (Novelette).
Acids and bases:
* Acid dissociation constant
* Acid-base extraction
* Acid-base reaction
* Acid-base physiology
* Acid-base homeostasis
* Dissociation constant
* Acidity function
* Buffer solutions
* pH
* Proton affinity
* Self-ionization of water
* Acids:
o Lewis acids
o Mineral acids
o Organic acids
o Strong acids
o Superacids
o Weak acids
* Bases:
o Lewis bases
o Organic bases
o Strong bases
o Superbases
o Non-nucleophilic bases
o Weak bases
edit
An acid (often represented by the generic formula HA [H+A-]) is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity greater than in pure water, i.e. a pH less than 7.0. That approximates the modern definition of Johannes Nicolaus Brønsted and Martin Lowry, who independently defined an acid as a compound which donates a hydrogen ion (H+) to another compound (called a base). Common examples include acetic acid (in vinegar) and sulfuric acid (used in car batteries). Acid/base systems are different from redox reactions in that there is no change in oxidation state.
Contents
[hide]
* 1 Definitions
* 2 Properties
* 3 Nomenclature
* 4 Chemical characteristics
o 4.1 Monoprotic acids
o 4.2 Polyprotic acids
o 4.3 Neutralization
o 4.4 Weak acid/weak base equilibria
* 5 Applications of acids
* 6 Biological occurrence
* 7 Common acids
o 7.1 Mineral acids
o 7.2 Sulfonic acids
o 7.3 Carboxylic acids
o 7.4 Vinylogous carboxylic acids
* 8 References
* 9 See also
* 10 External links
[edit] Definitions
Main article: acid-base reaction theories
The word "acid" comes from the Latin acidus meaning "sour," but in chemistry the term acid has a more specific meaning. There are four common ways to define an acid:
* Arrhenius: According to this definition developed by the Swedish chemist Svante Arrhenius, an acid is a substance that increases the concentration of hydrogen ions (H+), which are carried as hydronium ions (H3O+) when dissolved in water, while bases are substances that increase the concentration of hydroxide ions (OH-). This definition limits acids and bases to substances that can dissolve in water. Around 1800, many French chemists, including Antoine Lavoisier, incorrectly believed that all acids contained oxygen. Indeed the modern German word for oxygen is Sauerstoff (lit. sour substance), as is the Afrikaans word for oxygen suurstof, with the same meaning. English chemists, including Sir Humphry Davy, at the same time believed all acids contained hydrogen. Arrhenius used this belief to develop this definition of acid.
* Brønsted-Lowry: According to this definition, an acid is a proton (hydrogen nucleus) donor and a base is a proton acceptor. The acid is said to be dissociated after the proton is donated. An acid and the corresponding base are referred to as conjugate acid-base pairs. Brønsted and Lowry independently formulated this definition, which includes water-insoluble substances not in the Arrhenius definition. Acids according to this definition are variously referred to as Brønsted acids, Brønsted-Lowry acids, proton acids, protic acids, or protonic acids.
* Solvent-system definition: According to this definition, an acid is a substance that, when dissolved in an autodissociating solvent, increases the concentration of the solvonium cations, such as H3O+ in water, NH4+ in liquid ammonia, NO+ in liquid N2O4, SbCl2+ in SbCl3, etc. Base is defined as the substance that increases the concentration of the solvate anions, respectively OH-, NH2-, NO3-, or SbCl4-. This definition extends acid-base reactions to non-aqueous systems and even some aprotic systems, where no hydrogen nuclei are involved in the reactions. This definition is not absolute, a compound acting as acid in one solvent may act as a base in another.
* Lewis: According to this definition developed by Gilbert N. Lewis, an acid is an electron-pair acceptor and a base is an electron-pair donor. (These are frequently referred to as "Lewis acids" and "Lewis bases," and are electrophiles and nucleophiles, respectively, in organic chemistry; Lewis bases are also ligands in coordination chemistry.) Lewis acids include substances with no transferable protons (ie H+ hydrogen ions), such as iron(III) chloride, and hence the Lewis definition of an acid has wider application than the Brønsted-Lowry definition. In fact, the term Lewis acid is often used to exclude protic (Brønsted-Lowry) acids. The Lewis definition can also be explained with molecular orbital theory. In general, an acid can receive an electron pair in its lowest unoccupied orbital (LUMO) from the highest occupied orbital (HOMO) of a base. That is, the HOMO from the base and the LUMO from the acid combine to a bonding molecular orbital.
Although not the most general theory, the Brønsted-Lowry definition is the most widely used definition. The strength of an acid may be understood by this definition by the stability of hydronium and the solvated conjugate base upon dissociation. Increasing or decreasing stability of the conjugate base will increase or decrease the acidity of a compound. This concept of acidity is used frequently for organic acids such as carboxylic acid. The molecular orbital description, where the unfilled proton orbital overlaps with a lone pair, is connected to the Lewis definition.
[edit] Properties
Bronsted-Lowry acids:
* Are generally sour in taste
* Strong or concentrated acids often produce a stinging feeling on mucous membranes
* Change the color of pH indicators as follows: turn blue litmus and methyl orange red, turn phenolphthalein colorless
* React with metals to produce a metal salt and hydrogen
* React with metal carbonates to produce water, CO2 and a salt
* React with a base to produce a salt and water
* React with a metal oxide to produce water and a salt
* Conduct electricity, depending on the degree of dissociation
* Produce solvonium ions, such as hydronium (H3O+) ions in water
Acids can be gases, liquids, or solids. Respective examples (at 20 °C and 1 atm) are hydrogen chloride, sulfuric acid and citric acid. Solutions of acids in water are liquids, such as hydrochloric acid - an aqueous solution of hydrogen chloride. At 20 °C and 1 atm, linear carboxylic acids are liquids up to nonanoic acid (nine carbon atoms) and solids beginning from decanoic acid (ten carbon atoms). Aromatic carboxylic acids, the simplest being benzoic acid, are solids.
Strong acids and many concentrated acids, being corrosive, can be dangerous; causing severe burns for even minor contact. Generally, acid burns on the skin are treated by rinsing the affected area abundantly with running water, followed up with immediate medical attention. In the case of highly concentrated mineral acids such as sulfuric acid or nitric acid, the acid should first be wiped off, otherwise the exothermic mixing of the acid and the water could cause thermal burns.[citation needed] Particular acids may also be dangerous for reasons not related to their acidity. Material Safety Data Sheets (MSDS) can be consulted for detailed information on dangers and handling instructions.
[edit] Nomenclature
In the classical naming system, acids are named according to their anions. That ionic suffix is dropped and replaced with a new suffix (and sometimes prefix), according to the table below. For example, HCl has chloride as its anion, so the -ide suffix makes it take the form hydrochloric acid. In the IUPAC naming system, "aqueous" is simply added to the name of the ionic compound. Thus, for hydrogen chloride, the IUPAC name would be aqueous hydrogen chloride.
Classical naming system:
Anion Prefix Anion Suffix Acid Prefix Acid Suffix Example
per ate per ic acid perchloric acid (HClO4)
ate ic acid chloric acid (HClO3)
ite ous acid chlorous acid (HClO2)
hypo ite hypo ous acid hypochlorous acid (HClO)
ide hydro ic acid hydrochloric acid (HCl)
[edit] Chemical characteristics
In water the following equilibrium occurs between a weak acid (HA) and water, which acts as a base:
HA(aq) + H2O ⇌ H3O+(aq) + A-(aq)
The acidity constant (or acid dissociation constant) is the equilibrium constant for the reaction of HA with water:
K_a = \frac{[\mbox{H}_3\mbox{O}^+][\mbox{A}^-]}{[\mbox{HA}]}
Strong acids have large Ka values (i.e. the reaction equilibrium lies far to the right; the acid is almost completely dissociated to H3O+ and A-). Strong acids include the heavier hydrohalic acids: hydrochloric acid (HCl), hydrobromic acid (HBr), and hydroiodic acid (HI). (However, hydrofluoric acid, HF, is relatively weak.) For example, the Ka value for hydrochloric acid (HCl) is 107.
Weak acids have small Ka values (i.e. at equilibrium significant amounts of HA and A− exist together in solution; modest levels of H3O+ are present; the acid is only partially dissociated). For example, the Ka value for acetic acid is 1.8 x 10-5. Most organic acids are weak acids. Oxoacids, which tend to contain central atoms in high oxidation states surrounded by oxygen may be quite strong or weak. Nitric acid, sulfuric acid, and perchloric acid are all strong acids, whereas nitrous acid, sulfurous acid and hypochlorous acid are all weak.
Note on terms used:
* The terms "hydrogen ion" and "proton" are used interchangeably; both refer to H+.
* In aqueous solution, the water is protonated to form hydronium ion, H3O+(aq). This is often abbreviated as H+(aq) even though the symbol is not chemically correct.
* The strength of an acid is measured by its acid dissociation constant (Ka) or equivalently its pKa (pKa= - log(Ka)).
* The pH of a solution is a measurement of the concentration of hydronium. This will depend on the concentration and nature of acids and bases in solution.
[edit] Monoprotic acids
Monoprotic acids are those acids that are able to donate one proton per molecule during the process of dissociation (sometimes called ionization) as shown below (symbolized by HA):
HA(aq) + H2O(l) ⇌ H3O+(aq) + A−(aq) Ka
Common examples of monoprotic acids in mineral acids include hydrochloric acid (HCl) and nitric acid (HNO3). On the other hand, for organic acids the term mainly indicates the presence of one carboxyl group and sometimes these acids are known as monocarboxylic acid. Examples in organic acids include formic acid (HCOOH), acetic acid (CH3COOH) and benzoic acid (C6H5COOH).
[edit] Polyprotic acids
Polyprotic acids are able to donate more than one proton per acid molecule, in contrast to monoprotic acids that only donate one proton per molecule. Specific types of polyprotic acids have more specific names, such as diprotic acid (two potential protons to donate) and triprotic acid (three potential protons to donate).
A diprotic acid (here symbolized by H2A) can undergo one or two dissociations depending on the pH. Each dissociation has its own dissociation constant, Ka1 and Ka2.
H2A(aq) + H2O(l) ⇌ H3O+(aq) + HA−(aq) Ka1
HA−(aq) + H2O(l) ⇌ H3O+(aq) + A2−(aq) Ka2
The first dissociation constant is typically greater than the second; i.e., Ka1 > Ka2 . For example, sulfuric acid (H2SO4) can donate one proton to form the bisulfate anion (HSO4−), for which Ka1 is very large; then it can donate a second proton to form the sulfate anion (SO42−), wherein the Ka2 is intermediate strength. The large Ka1 for the first dissociation makes sulfuric a strong acid. In a similar manner, the weak unstable carbonic acid (H2CO3) can lose one proton to form bicarbonate anion (HCO3−) and lose a second to form carbonate anion (CO32−). Both Ka values are small, but Ka1 > Ka2 .
A triprotic acid (H3A) can undergo one, two, or three dissociations and has three dissociation constants, where Ka1 > Ka2 > Ka3 .
H3A(aq) + H2O(l) ⇌ H3O+(aq) + H2A−(aq) Ka1
H2A−(aq) + H2O(l) ⇌ H3O+(aq) + HA2−(aq) Ka2
HA2−(aq) + H2O(l) ⇌ H3O+(aq) + A3−(aq) Ka3
An inorganic example of a triprotic acid is orthophosphoric acid (H3PO4), usually just called phosphoric acid. All three protons can be successively lost to yield H2PO4−, then HPO42−, and finally PO43− , the orthophosphate ion, usually just called phosphate. An organic example of a triprotic acid is citric acid, which can successively lose three protons to finally form the citrate ion. Even though the positions of the protons on the original molecule may be equivalent, the successive Ka values will differ since it is energetically less favorable to lose a proton if the conjugate base is more negatively charged.
[edit] Neutralization
Hydrochloric acid (in beaker) reacting with ammonia fumes to produce ammonium chloride (white smoke).
Hydrochloric acid (in beaker) reacting with ammonia fumes to produce ammonium chloride (white smoke).
Neutralization is the reaction between an acid and a base, producing a salt and neutralized base; for example, hydrochloric acid and sodium hydroxide form sodium chloride and water:
HCl(aq) + NaOH(aq) → H2O(l) + NaCl(aq)
Neutralization is the basis of titration, where a pH indicator shows equivalence point when the equivalent number of moles of a base have been added to an acid. It is often wrongly assumed that neutralization should result in a solution with pH 7.0, which is only the case with similar acid and base strengths during a reaction.
Neutralization with a base weaker than the acid results in a weakly acidic salt. An example is the weakly acidic ammonium chloride, which is produced from the strong acid hydrogen chloride and the weak base ammonia. Conversely, neutralizing a weak acid with a strong base gives a weakly basic salt, e.g. sodium fluoride from hydrogen fluoride and sodium hydroxide.
[edit] Weak acid/weak base equilibria
Main article: Henderson-Hasselbalch equation
In order to lose a proton, it is necessary that the pH of the system rise above the pKa of the protonated acid. The decreased concentration of H+ in that basic solution shifts the equilibrium towards the conjugate base form (the deprotonated form of the acid). In lower-pH (more acidic) solutions, there is a high enough H+ concentration in the solution to cause the acid to remain in its protonated form, or to protonate its conjugate base (the deprotonated form).
Solutions of weak acids and salts of their conjugate bases form buffer solutions.
[edit] Applications of acids
There are numerous uses for acids. Acids are often used to remove rust and other corrosion from metals in a process known as pickling. They may be used as an electrolyte in a wet cell battery, such as sulfuric acid in a car battery.
Strong acids, sulfuric acid in particular, are widely used in mineral processing. For example, phosphate minerals react with sulfuric acid to produce phosphoric acid for the production of phosphate fertilizers, and zinc is produced by dissolving zinc oxide into sulfuric acid, purifying the solution and electrowinning.
In the chemical industry, acids react in neutralization reactions to produce salts. For example, nitric acid reacts with ammonia to produce ammonium nitrate, a fertilizer. Additionally, carboxylic acids can be esterified with alcohols, to produce esters.
Acids are used as catalysts; for example, sulfuric acid is used in very large quantities in the alkylation process to produce gasoline. Strong acids, such as sulfuric, phosphoric and hydrochloric acids also effect dehydration and condensation reactions.
Acids are used as additives to drinks and foods, as they alter their taste and serve as preservatives. Phosphoric acid, for example, is component of cola drinks.
[edit] Biological occurrence
In humans and many other animals, hydrochloric acid is a part of the gastric acid secreted within the stomach to help hydrolyze proteins and polysaccharides, as well as converting the inactive pro-enzyme, pepsinogen into the enzyme, pepsin. Some organisms produce acids for defense; for example, ants produce formic acid.
[edit] Common acids
[edit] Mineral acids
* Solutions of hydrogen halides, such as hydrochloric acid (HCl) and hydrobromic acid (HBr)
* Sulfuric acid (H2SO4)
* Nitric acid (HNO3)
* Phosphoric acid (H3PO4)
* Chromic acid (H2CrO4)
[edit] Sulfonic acids
* Methanesulfonic acid (aka mesylic acid) (MeSO3H)
* Ethanesulfonic acid (aka esylic acid) (EtSO3H)
* Benzenesulfonic acid (aka besylic acid) (PhSO3H)
* Toluenesulfonic acid (aka tosylic acid, or (C6H4(CH3) (SO3H))
[edit] Carboxylic acids
* Formic acid
* Acetic acid
* Citric acid
[edit] Vinylogous carboxylic acids
* Ascorbic acid
"TRIGONOMETRY"
TRIGONOMENTRY IDEANTITIES
Summary of trigonometric identities
You have seen quite a few trigonometric identities in the past few pages. It is convenient to have a summary of them for reference. These identities mostly refer to one angle denoted t, but there are a few of them involving two angles, and for those, the other angle is denoted s..
More important identities
You don't have to know all the identities off the top of your head. But these you should.
Defining relations for tangent, cotangent, secant, and cosecant in terms of sine and cosine.
tan t = sin tcos t cot t = 1tan t = cos tsin t
sec t = 1cos t csc t = 1sin t
The Pythagorean formula for sines and cosines.
sin2 t + cos2 t = 1
Identities expressing trig functions in terms of their complements
cos t = sin( pi/2 – t) sin t = cos( pi/2 – t)
cot t = tan( pi/2 – t) tan t = cot( pi/2 – t)
csc t = sec( pi/2 – t) sec t = csc( pi/2 – t)
Periodicity of trig functions. Sine, cosine, secant, and cosecant have period 2 pi while tangent and cotangent have period pi.
sin (t + 2 pi) = sin t
cos (t + 2 pi) = cos t
tan (t + pi) = tan t
Identities for negative angles. Sine, tangent, cotangent, and cosecant are odd functions while cosine and secant are even functions.
sin –t = –sin t
cos –t = cos t
tan –t = –tan t
Sum formulas for sine and cosine
sin (s + t) = sin s cos t + cos s sin t
cos (s + t) = cos s cos t – sin s sin t
Double angle formulas for sine and cosine
sin 2t = 2 sin t cos t
cos 2t = cos2 t – sin2 t = 2 cos2 t – 1 = 1 – 2 sin2 t
Less important identities
You should know that there are these identities, but they are not as important as those mentioned above. They can all be derived from those above, but sometimes it takes a bit of work to do so.
The Pythagorean formula for tangents and secants.
sec2 t = 1 + tan2 t
Identities expressing trig functions in terms of their supplements
sin( pi – t) = sin t
cos( pi – t) = –cos t
tan( pi – t) = –tan t
Difference formulas for sine and cosine
sin (s – t) = sin s cos t – cos s sin t
cos (s – t) = cos s cos t + sin s sin t
Sum, difference, and double angle formulas for tangent
tan (s + t) = tan s + tan t1 – tan s tan t
tan (s – t) = tan s – tan t1 + tan s tan t
tan 2t = 2 tan t1 – tan2 t
Half-angle formulas
sin t/2 = ± sqrt((1 – cos t) / 2)
cos t/2 = ± sqrt((1 + cos t) / 2)
tan t/2 = sin t1 + cos t = 1 – cos tsin t
Truly obscure identities
These are just here for perversity. Yes, of course, they have some applications, but they're usually narrow applications, and they could just as well be forgotten until, if ever, needed.
Product-sum identities
sin s + sin t = 2 sin s + t2 cos s – t2
sin s – sin t = 2 cos s + t2 sin s – t2
cos s + cos t = 2 cos s + t2 cos s – t2
cos s – cos t = –2 sin s + t2 sin s – t2
Product identities
sin s cos t = sin (s + t) + sin (s – t)2
cos s cos t = cos (s + t) + cos (s – t)2
sin s sin t = cos (s – t) – cos (s + t) 2
Aside: weirdly enough, these product identities were used before logarithms to perform multiplication. Here's how you could use the second one. If you want to multiply x times y, use a table to look up the angle s whose cosine is x and the angle t whose cosine is y. Look up the cosines of the sum s + t, and the difference s – t. Average those two cosines. You get the product xy! Three table look-ups, and computing a sum, a difference, and an average rather than one multiplication. Tycho Brahe (1546-1601), among others, used this algorithm known as prosthaphaeresis.
Triple angle formulas. You can easily reconstruct these from the addition and double angle formulas.
sin 3t = 3 sin t – 4 sin3 t
cos 3t = 4 cos3 t –3 cos t
tan 3t = 3 tan t – tan3t1 – 3 tan2t
More half-angle formulas. (These are used in calculus for a particular kind of substitution in integrals sometimes called the Weierstrass t-substitution.)
sin t = 2 tan t/21 + tan2 t/2
cos t = 1 – tan2 t/21 + tan2 t/2
tan t = 2 tan t/21 – tan2 t/2
Summary of trigonometric identities
You have seen quite a few trigonometric identities in the past few pages. It is convenient to have a summary of them for reference. These identities mostly refer to one angle denoted t, but there are a few of them involving two angles, and for those, the other angle is denoted s..
More important identities
You don't have to know all the identities off the top of your head. But these you should.
Defining relations for tangent, cotangent, secant, and cosecant in terms of sine and cosine.
tan t = sin tcos t cot t = 1tan t = cos tsin t
sec t = 1cos t csc t = 1sin t
The Pythagorean formula for sines and cosines.
sin2 t + cos2 t = 1
Identities expressing trig functions in terms of their complements
cos t = sin( pi/2 – t) sin t = cos( pi/2 – t)
cot t = tan( pi/2 – t) tan t = cot( pi/2 – t)
csc t = sec( pi/2 – t) sec t = csc( pi/2 – t)
Periodicity of trig functions. Sine, cosine, secant, and cosecant have period 2 pi while tangent and cotangent have period pi.
sin (t + 2 pi) = sin t
cos (t + 2 pi) = cos t
tan (t + pi) = tan t
Identities for negative angles. Sine, tangent, cotangent, and cosecant are odd functions while cosine and secant are even functions.
sin –t = –sin t
cos –t = cos t
tan –t = –tan t
Sum formulas for sine and cosine
sin (s + t) = sin s cos t + cos s sin t
cos (s + t) = cos s cos t – sin s sin t
Double angle formulas for sine and cosine
sin 2t = 2 sin t cos t
cos 2t = cos2 t – sin2 t = 2 cos2 t – 1 = 1 – 2 sin2 t
Less important identities
You should know that there are these identities, but they are not as important as those mentioned above. They can all be derived from those above, but sometimes it takes a bit of work to do so.
The Pythagorean formula for tangents and secants.
sec2 t = 1 + tan2 t
Identities expressing trig functions in terms of their supplements
sin( pi – t) = sin t
cos( pi – t) = –cos t
tan( pi – t) = –tan t
Difference formulas for sine and cosine
sin (s – t) = sin s cos t – cos s sin t
cos (s – t) = cos s cos t + sin s sin t
Sum, difference, and double angle formulas for tangent
tan (s + t) = tan s + tan t1 – tan s tan t
tan (s – t) = tan s – tan t1 + tan s tan t
tan 2t = 2 tan t1 – tan2 t
Half-angle formulas
sin t/2 = ± sqrt((1 – cos t) / 2)
cos t/2 = ± sqrt((1 + cos t) / 2)
tan t/2 = sin t1 + cos t = 1 – cos tsin t
Truly obscure identities
These are just here for perversity. Yes, of course, they have some applications, but they're usually narrow applications, and they could just as well be forgotten until, if ever, needed.
Product-sum identities
sin s + sin t = 2 sin s + t2 cos s – t2
sin s – sin t = 2 cos s + t2 sin s – t2
cos s + cos t = 2 cos s + t2 cos s – t2
cos s – cos t = –2 sin s + t2 sin s – t2
Product identities
sin s cos t = sin (s + t) + sin (s – t)2
cos s cos t = cos (s + t) + cos (s – t)2
sin s sin t = cos (s – t) – cos (s + t) 2
Aside: weirdly enough, these product identities were used before logarithms to perform multiplication. Here's how you could use the second one. If you want to multiply x times y, use a table to look up the angle s whose cosine is x and the angle t whose cosine is y. Look up the cosines of the sum s + t, and the difference s – t. Average those two cosines. You get the product xy! Three table look-ups, and computing a sum, a difference, and an average rather than one multiplication. Tycho Brahe (1546-1601), among others, used this algorithm known as prosthaphaeresis.
Triple angle formulas. You can easily reconstruct these from the addition and double angle formulas.
sin 3t = 3 sin t – 4 sin3 t
cos 3t = 4 cos3 t –3 cos t
tan 3t = 3 tan t – tan3t1 – 3 tan2t
More half-angle formulas. (These are used in calculus for a particular kind of substitution in integrals sometimes called the Weierstrass t-substitution.)
sin t = 2 tan t/21 + tan2 t/2
cos t = 1 – tan2 t/21 + tan2 t/2
tan t = 2 tan t/21 – tan2 t/2
Tuesday, October 7, 2008
"SCIENCE QUESTION BANK"
Q. 1. What is the diameter of a bucky ball?
Q. 2. Name the types of nanotubes.
Q. 3. What is the refractive index of water ?
Q. 4. Give the position and nature of image formed by a convex lens when the object is placed at F.
Q. 5. What is the SI unit of power of lens ?
Q. 6. What is the power of a concave lens having focal length 0.5m?
Q. 7. What is the velocity of light in vacuum?
Q. 8. Comment on the refractive index of any medium.
Q. 9. At what position will a concave mirror give a real, inverted image of same size as the object?
Q. 10. Which kind of lens has positive power?
Q. 11. Which colour is obtained at the top in a prism spectrum and why?
Q. 12. If white light is incident on a mixture of blue and yellow pigments, which colour is reflected?
Q. 13. Which technique is used to produce coloured pictures on T V?
Q. 14. Name the primary pigments.
Q. 15. Which lens is used to correct Hypermetropia?
Q. 16. In a telescope, which lens has a larger focal length?
Q. 17. If an electrical lamp lights for 2 hrs drawing a current of 0.4 A, calculate the amount of charge that passed through the lamp?
Q. 18. Define electric potential.
Q. 19.How much current will an electric heater connected to 220 V line draw if its resistance is 45 ohm?
Q. 20. How much energy is consumed in joules if the domestic meter reading shows 15.5 units?
Q. 21. Out of tap water, sea water and pure water, which is the best conductor of electricity?
Q. 22. What type of V-> I graph does ohm’s law suggest?
Q. 23. Why does a solenoid produce a strong magnetic field?
Q. 24. What is the frequency of domestic current?
Q. 25. Which electromagnetic rays have wave length less than ultraviolet rays?
Q. 26. What keeps the water circulating in the tank of a solar water heater?
Q. 27. What temperature is attained at the Mount Louis in France by Solar furnace?
Q. 28. How much electricity is produced by a single solar cell?
Q. 29. Which are the necessary structural parameters of a windmill?
Q. 30. At what depth is OTEC captured?
Q. 31. Where on Earth can OTEC be captured?
Q. 32. Define Magma.
Q. 33. What is the average temperature obtained in hot water geysers?
Q. 34. Where is hydrogen used as a fuel?
Q. 35. How many carbon atoms are present in a molecule of diesel?
Q. 36. What is the calorific value of kerosene?
Q. 37. At what temperature is Lubricating oil obtained in the FD tower?
Q. 38. What is the specific heat of water?
Q. 39. 1 eV is how many joules?
Q. 40. 1 u is how many eV?
Q. 41. What is the atomic mass of a neutron?
Q. 42. How much energy does fission of 1kg uranium produce?
Q. 43. Define spontaneous fission.
Q. 44. What is the energy of neutron released during nuclear fission?
Q. 45. How much is the energy of a neutron decreased to obtain a thermal neutron?
Q. 46. Mass defect is converted to energy as per which equation?
Q. 47. At what temperature is plasma state obtained?
Q. 48. Define Ignition temperature.
Q. 49. When and where did the most serious nuclear accident take place?
Q. 50. What is the value of solar mass?
Q. 51. What is the value of solar constant?
Q. 52. Name the moons of Mars.
Q. 53. Name the moons of Neptune.
Q. 54. With respect to Pluto what is Binary system?
Q. 55. What is the tail of a comet made up of?
Q. 56. After what height do booster rockets burn due to friction?
Q. 57. In which orbits are remote sensing satellites launched?
Q. 58. From where was the first EDUSAT launched in India?
Q. 59. Which satellite to be launched by India will be useful for DTH service?
Q. 60. Give an example of physical equilibrium.
Q. 61. What kind of reaction should take place for attaining chemical equilibrium?
Q. 62. Draw the graph of rate of reaction à time.
Q. 63. How does temperature affect rate of reaction?
Q. 64. What is the concentration of H+ ion in pure water?
Q. 65. What is the pH value of Lemon Juice?
Q. 66. Give the chemical formula of ammonical brine.
Q. 67. Give chemical formula of soda ash.
Q. 68. What is efflorescence?
Q. 69. What is dead burnt plaster?
Q. 70. What is lime-light?
Q. 71. What happens when lime is heated with carbon in an electric furnace?
Q. 72. Name the major constituents of cement?
Q. 73. Give the chemical formula of glass.
Q. 74. What is added to make green coloured glass?
Q. 75. Write the full form of RCC.
Q. 76. Give the names and chemical formulae of ores of silver.
Q. 77. Give an equation for thermite process.
Q. 78. What is added to alumina to bring down its melting point in Hall- Heroult process?
Q. 79. Define emf series.
Q. 80. Which metals do not react with water at all?
Q. 81. Give the equation for formation of rust.
Q. 82. How is galvanized iron made?
Q. 83. Which alloy is used to make light instruments?
Q. 84. Which metals are refined by liquification process?
Q. 85. What is slag?
Q. 86. What product is obtained when phosphorus pentoxide dissolves in water?
Q. 87. Give the equation for steam reforming process.
Q. 88. What catalyst is used in Haber’s process?
Q. 89. Which base is used to make para-aminobenzoic acid?
Q. 90. What is the melting point of sulphur?
Q. 91. Give the chemical formula of copper pyrite.
Q. 92. At what temperature is rhombic sulphur obtained?
Q. 93. What is used as a preservative in jams and squashes?
Q. 94. What is used as a catalyst in the contact chamber to convert sulphur dioxide to trioxide?
Q. 95. Give an example showing dehydrating action of sulphuric acid.
Q. 96. give the chemical name and formula or oleum.
Q. 97. Give the chemical formula and IUPAC name for propyl alcohol.
Q. 98. Which enzyme converts sugar to glucose?
Q. 99. Ethyl alcohol undergoes oxidation in presence of acetic acid and chromium oxide to give?
Q. 100. Why is ethyl alcohol used in radiators of vehicles in cold countries?
Q. 101. What is denatured ethyl alcohol?
Q. 102. How many hydrocarbons can be attached to a ketone group?
Q. 103. What does the oxidation of alcohols give?
Q. 104. What is formalin and where is it used?
Q. 105. Give the reaction between methanal and hydrogen cyanide.
Q. 106. Give the general formula of carboxylic group.
Q. 107. What is used as a catalyst to prepare acetic acid industrially?
Q. 108. Give the name and chemical formula for monomer of Teflon.
Q. 109. What is the name and chemical formula of monomer unit of natural rubber?
Q. 110. Give the name and chemical formula of the by product obtained in while manufacturing soap.
Q. 111. Which functional group is present in detergents?
Q. 112. What is the function of polar tail of detergent molecule?
Q. 113. What is holozoic nutrition?
Q. 114. What is the full form of NADP?
Q. 115. Where does the biosynthetic phase of photosynthesis take place?
Q. 116. How are ATP and NADPH2 synthesised in light phase useful in biosynthetic phase?
Q. 117. Which organ in grasshopper grinds the food particles?
Q. 118. In mammals, which teeth are used for grinding and chewing?
Q. 119. Which are the parts of small intestine?
Q. 120. What is the function of villi present in small intestine?
Q. 121. How many times more energy is released by oxidation of a glucose molecue by aerobic respiration compared to anaerobic respiration?
Q. 122. What is the function of lenticels?
Q. 123. What will you expect in stomata when the carbondioxide concentration increases in the leaf?
Q. 124. What are the openings of trachea called?
Q. 125. Where does each bronchile terminate?
Q. 126. During photosynthesis electrons are released from which molecule?
Q. 127. During photosynthesis from where is oxygen released?
Q. 128. What is the function of incisors?
Q. 129. Where is NADPH2 formed?
Q. 130. What provides tensile strength to the inner wall of tracheae?
Q. 131. Through which organ are water and minerals transported in pteridiphytes and gymnosperms?
Q. 132. What is ascent of sap?
Q. 133. How are sieve tube and companion cell formed?
Q. 134. What controls the actions of sieve tube?
Q. 135. Which organ transports food in pteridophytes and gymnosperms?
Q. 136. How do food particles enter phloem?
Q. 137. What is translocation?
Q. 138. What is conjugated protein?
Q. 139. Where are erythrocytes formed?
Q. 140. Which type of WBC produces immunoglobulins?
Q. 141. What converts prothrombin to thrombin while blood clotting?
Q. 142. Where are antigens present?
Q. 143. A person with O blood group will not have which type of antigen?
Q. 144. What is the function of tricuspid valve?
Q. 145. In context to human heart what is known as diastolic stage?
Q. 146. Why are the walls of arteries elastic and thick?
Q. 147. Why do veins contain valves?
Q. 148. What is lymph?
Q. 149. Name the excretory organ of sponges.
Q. 150. What is the opening of nephrostome called?
Q. 151.Which type of nephridia will show exonephric excretion?
Q. 152. What is malphigian body?
Q. 153. Where do the collecting tubules of nephron open?
Q. 154. What is ultrafilteration of urine?
Q. 155. In which form is concentrated waste formed in desert animals and why?
Q. 156. How do birds excrete waste?
Q. 157. Which part helps amoeba in excretion?
Q. 158. State the function and location of stem cell?
Q. 159.> What is the shape of human erythrocyte?
Q. 160. In which part of the body does impure blood get purified?
Q. 161. What is chemotropism?
Q. 162. What is thigmonastic response?
Q. 163. Which type of nastic movement does sunflower show?
Q. 164. Which type of plants do not respond to photoperiodism?
Q. 165. What induces photoperiodic stimulus in plants?
Q. 166. What type of nervous system is present in invertebrates?
Q. 167. which organs protect the human brain?
Q. 168. Where is the cerebrospinal fluid present and what is its function?
Q. 169. where are the centres for visual reception, in brain?
Q. 170. What is the function of cerebellum?
Q. 171. Medulla possesses centres for ?
Q. 172. How many pairs of spinal nerves arise from the spinal cord?
Q. 173. What is reflex arc?
Q. 174. What is autonomous nervous system?
Q. 175. Give two characteristics of hormones
Q. 176. Which organ controls the functioning of pituitary gland?
Q. 177. Which hormone maintains the ionic balance in the body?
Q. 178. What is the function of oxytocin?
Q. 179. What are the functions of estrogen and progesterone?
Q. 180. Which hormone regulates the male sex organs?
Q. 181. Which hormone acts as a growth promoter in plants?
Q. 182. What is the group of cells formed in multiple fission called?
Q. 183. Name two organisms reproducing by spore formation?
Q. 184. By which method do planaria and spirogyra reproduce?
Q. 185. Name two plants showing layering mode of vegetative propogation.
Q. 186. Which plants can be rafted on the stock of citrus?
Q. 187. Q. 1. What is the portion of the plant grafted on other plant called?
Q. 188. What is the temperature in the scortum?
Q. 189. Why is the ureter known as urinogenital path in case of males?
Q. 190. Which glands secrete semen?
Q. 191. What gives rise to an ovum in female?
Q. 192. What is ovulation in females?
Q. 193. is menopause?
Q. 194. What is copulation?
Q. 195. What is the function of amniotic fluid?
Q. 196. What is the zero method of natural contraception?
Q. 197. What do oral pills for contraception contain?
Q. 198. Name the organism causing Gonorrhoea.
Q. 199. Which scientists provided and evidence that gene is a part of chromosome?
Q. 200. What are prokaryotic chromosomes composed of ?
Q. 201. What is the length and diameter of each chromosome?
Q. 202. What is nucleolar organizer region?
Q. 203. Which purine nitrogen bases are present in the DNA molecule?
Q. 204. Which is the complimentary base pair of Cytosine?
Q. 205. What is the distance between each nucleotide pair in a DNA strand?
Q. 206. In which animal, the embryo develops into a female at high temperature?
Q. 207. What does the Recapitulation theory of Ernst Haeckel state?
Q. 208. Who is known as the Father of Taxonomy?
Q. 209. What is retrovirus? Give an example.
Q. 210. What is the extra chromosome found in male insects called?
Q. 211. How do CFC’s harm the atmosphere?
Q. 212. For what purpose are wet scrubbers used?
Q. 213. What is Eutrophication?
Q. 214. Why is the BOD of potable water less?
Q. 215. What is the full form of NEERI?
Q. 216. Define 1 A current.
Q. 217. What symbol is used in an electrical circuit to show inductor?
Q. 218. Comment on the voltage drop across a series connection.
Q. 219. Is it advisable to connect appliances in series connection domestically? Justify your answer.
Q. 220. 1 volt ampere is how many kW?
Q. 221. What is the nature and size of image formed by a convex lens when the object is at 2F?
Q. 222.What is the function of ciliary muscles?
Q. 223.Why is a voltmeter always connected in parallel in an electrical circuit?
Q. 224.A lamp of 100W glows for 2 hrs daily. Calculate the energy consumed in 30 days.
Q. 225. Define electroplating.
Q. 226. Name two addition and two condensation polymers.
Q. 227. What is the wavelength of visible light?
Q. 228. Where in Gujarat are wind farms located?
Q. 229. From which places is geothermal energy obtained in Gujarat?
Q. 230. What is the carbon content in anthracite?
Q. 231. Give two uses of Coke.
Q. 232. What gas is added in LPG cylinders to detect any leakage?
Q. 233. Which power station in Gujarat uses natural gas as a fuel?
Q. 234. What is the calorific value of hydrogen?
Q. 235. Which substances are used as coolants in nuclear reactors?
Q. 236. Name the moons of Saturn.
Q. 237. What are asteroids composed of?
Q. 238. How far is sun located from the galactic centre?
Q. 239. Which type of stars is found mostly in elliptical galaxies?
Q. 240. Give two properties of Rocket fuel.
Q. 241. What is the calorific vale of biogas?
Q. 242. Write the full form of GSLV.
Q. 243. Which satellite is used for weather forecasting?
Q. 244. What needs to be retrieved in Solvay’s ammonia soda process?
Q. 245. Which compound is used as an antacid?
Q. 246. Write the equation of the reaction taking place on inert anode in the electrolysis of molten NaCl.
Q. 247. Why is hydrogen used in welding metals?
Q. 248. At what temperature is rubber heated with sulphur to get vulcanized rubber?
Q. 249. What is the function of hepatic caecae found is digestive system of grasshopper?
Q. 250. During fission process what are the respective atomic masses of the elements obtained?
Q. 2. Name the types of nanotubes.
Q. 3. What is the refractive index of water ?
Q. 4. Give the position and nature of image formed by a convex lens when the object is placed at F.
Q. 5. What is the SI unit of power of lens ?
Q. 6. What is the power of a concave lens having focal length 0.5m?
Q. 7. What is the velocity of light in vacuum?
Q. 8. Comment on the refractive index of any medium.
Q. 9. At what position will a concave mirror give a real, inverted image of same size as the object?
Q. 10. Which kind of lens has positive power?
Q. 11. Which colour is obtained at the top in a prism spectrum and why?
Q. 12. If white light is incident on a mixture of blue and yellow pigments, which colour is reflected?
Q. 13. Which technique is used to produce coloured pictures on T V?
Q. 14. Name the primary pigments.
Q. 15. Which lens is used to correct Hypermetropia?
Q. 16. In a telescope, which lens has a larger focal length?
Q. 17. If an electrical lamp lights for 2 hrs drawing a current of 0.4 A, calculate the amount of charge that passed through the lamp?
Q. 18. Define electric potential.
Q. 19.How much current will an electric heater connected to 220 V line draw if its resistance is 45 ohm?
Q. 20. How much energy is consumed in joules if the domestic meter reading shows 15.5 units?
Q. 21. Out of tap water, sea water and pure water, which is the best conductor of electricity?
Q. 22. What type of V-> I graph does ohm’s law suggest?
Q. 23. Why does a solenoid produce a strong magnetic field?
Q. 24. What is the frequency of domestic current?
Q. 25. Which electromagnetic rays have wave length less than ultraviolet rays?
Q. 26. What keeps the water circulating in the tank of a solar water heater?
Q. 27. What temperature is attained at the Mount Louis in France by Solar furnace?
Q. 28. How much electricity is produced by a single solar cell?
Q. 29. Which are the necessary structural parameters of a windmill?
Q. 30. At what depth is OTEC captured?
Q. 31. Where on Earth can OTEC be captured?
Q. 32. Define Magma.
Q. 33. What is the average temperature obtained in hot water geysers?
Q. 34. Where is hydrogen used as a fuel?
Q. 35. How many carbon atoms are present in a molecule of diesel?
Q. 36. What is the calorific value of kerosene?
Q. 37. At what temperature is Lubricating oil obtained in the FD tower?
Q. 38. What is the specific heat of water?
Q. 39. 1 eV is how many joules?
Q. 40. 1 u is how many eV?
Q. 41. What is the atomic mass of a neutron?
Q. 42. How much energy does fission of 1kg uranium produce?
Q. 43. Define spontaneous fission.
Q. 44. What is the energy of neutron released during nuclear fission?
Q. 45. How much is the energy of a neutron decreased to obtain a thermal neutron?
Q. 46. Mass defect is converted to energy as per which equation?
Q. 47. At what temperature is plasma state obtained?
Q. 48. Define Ignition temperature.
Q. 49. When and where did the most serious nuclear accident take place?
Q. 50. What is the value of solar mass?
Q. 51. What is the value of solar constant?
Q. 52. Name the moons of Mars.
Q. 53. Name the moons of Neptune.
Q. 54. With respect to Pluto what is Binary system?
Q. 55. What is the tail of a comet made up of?
Q. 56. After what height do booster rockets burn due to friction?
Q. 57. In which orbits are remote sensing satellites launched?
Q. 58. From where was the first EDUSAT launched in India?
Q. 59. Which satellite to be launched by India will be useful for DTH service?
Q. 60. Give an example of physical equilibrium.
Q. 61. What kind of reaction should take place for attaining chemical equilibrium?
Q. 62. Draw the graph of rate of reaction à time.
Q. 63. How does temperature affect rate of reaction?
Q. 64. What is the concentration of H+ ion in pure water?
Q. 65. What is the pH value of Lemon Juice?
Q. 66. Give the chemical formula of ammonical brine.
Q. 67. Give chemical formula of soda ash.
Q. 68. What is efflorescence?
Q. 69. What is dead burnt plaster?
Q. 70. What is lime-light?
Q. 71. What happens when lime is heated with carbon in an electric furnace?
Q. 72. Name the major constituents of cement?
Q. 73. Give the chemical formula of glass.
Q. 74. What is added to make green coloured glass?
Q. 75. Write the full form of RCC.
Q. 76. Give the names and chemical formulae of ores of silver.
Q. 77. Give an equation for thermite process.
Q. 78. What is added to alumina to bring down its melting point in Hall- Heroult process?
Q. 79. Define emf series.
Q. 80. Which metals do not react with water at all?
Q. 81. Give the equation for formation of rust.
Q. 82. How is galvanized iron made?
Q. 83. Which alloy is used to make light instruments?
Q. 84. Which metals are refined by liquification process?
Q. 85. What is slag?
Q. 86. What product is obtained when phosphorus pentoxide dissolves in water?
Q. 87. Give the equation for steam reforming process.
Q. 88. What catalyst is used in Haber’s process?
Q. 89. Which base is used to make para-aminobenzoic acid?
Q. 90. What is the melting point of sulphur?
Q. 91. Give the chemical formula of copper pyrite.
Q. 92. At what temperature is rhombic sulphur obtained?
Q. 93. What is used as a preservative in jams and squashes?
Q. 94. What is used as a catalyst in the contact chamber to convert sulphur dioxide to trioxide?
Q. 95. Give an example showing dehydrating action of sulphuric acid.
Q. 96. give the chemical name and formula or oleum.
Q. 97. Give the chemical formula and IUPAC name for propyl alcohol.
Q. 98. Which enzyme converts sugar to glucose?
Q. 99. Ethyl alcohol undergoes oxidation in presence of acetic acid and chromium oxide to give?
Q. 100. Why is ethyl alcohol used in radiators of vehicles in cold countries?
Q. 101. What is denatured ethyl alcohol?
Q. 102. How many hydrocarbons can be attached to a ketone group?
Q. 103. What does the oxidation of alcohols give?
Q. 104. What is formalin and where is it used?
Q. 105. Give the reaction between methanal and hydrogen cyanide.
Q. 106. Give the general formula of carboxylic group.
Q. 107. What is used as a catalyst to prepare acetic acid industrially?
Q. 108. Give the name and chemical formula for monomer of Teflon.
Q. 109. What is the name and chemical formula of monomer unit of natural rubber?
Q. 110. Give the name and chemical formula of the by product obtained in while manufacturing soap.
Q. 111. Which functional group is present in detergents?
Q. 112. What is the function of polar tail of detergent molecule?
Q. 113. What is holozoic nutrition?
Q. 114. What is the full form of NADP?
Q. 115. Where does the biosynthetic phase of photosynthesis take place?
Q. 116. How are ATP and NADPH2 synthesised in light phase useful in biosynthetic phase?
Q. 117. Which organ in grasshopper grinds the food particles?
Q. 118. In mammals, which teeth are used for grinding and chewing?
Q. 119. Which are the parts of small intestine?
Q. 120. What is the function of villi present in small intestine?
Q. 121. How many times more energy is released by oxidation of a glucose molecue by aerobic respiration compared to anaerobic respiration?
Q. 122. What is the function of lenticels?
Q. 123. What will you expect in stomata when the carbondioxide concentration increases in the leaf?
Q. 124. What are the openings of trachea called?
Q. 125. Where does each bronchile terminate?
Q. 126. During photosynthesis electrons are released from which molecule?
Q. 127. During photosynthesis from where is oxygen released?
Q. 128. What is the function of incisors?
Q. 129. Where is NADPH2 formed?
Q. 130. What provides tensile strength to the inner wall of tracheae?
Q. 131. Through which organ are water and minerals transported in pteridiphytes and gymnosperms?
Q. 132. What is ascent of sap?
Q. 133. How are sieve tube and companion cell formed?
Q. 134. What controls the actions of sieve tube?
Q. 135. Which organ transports food in pteridophytes and gymnosperms?
Q. 136. How do food particles enter phloem?
Q. 137. What is translocation?
Q. 138. What is conjugated protein?
Q. 139. Where are erythrocytes formed?
Q. 140. Which type of WBC produces immunoglobulins?
Q. 141. What converts prothrombin to thrombin while blood clotting?
Q. 142. Where are antigens present?
Q. 143. A person with O blood group will not have which type of antigen?
Q. 144. What is the function of tricuspid valve?
Q. 145. In context to human heart what is known as diastolic stage?
Q. 146. Why are the walls of arteries elastic and thick?
Q. 147. Why do veins contain valves?
Q. 148. What is lymph?
Q. 149. Name the excretory organ of sponges.
Q. 150. What is the opening of nephrostome called?
Q. 151.Which type of nephridia will show exonephric excretion?
Q. 152. What is malphigian body?
Q. 153. Where do the collecting tubules of nephron open?
Q. 154. What is ultrafilteration of urine?
Q. 155. In which form is concentrated waste formed in desert animals and why?
Q. 156. How do birds excrete waste?
Q. 157. Which part helps amoeba in excretion?
Q. 158. State the function and location of stem cell?
Q. 159.> What is the shape of human erythrocyte?
Q. 160. In which part of the body does impure blood get purified?
Q. 161. What is chemotropism?
Q. 162. What is thigmonastic response?
Q. 163. Which type of nastic movement does sunflower show?
Q. 164. Which type of plants do not respond to photoperiodism?
Q. 165. What induces photoperiodic stimulus in plants?
Q. 166. What type of nervous system is present in invertebrates?
Q. 167. which organs protect the human brain?
Q. 168. Where is the cerebrospinal fluid present and what is its function?
Q. 169. where are the centres for visual reception, in brain?
Q. 170. What is the function of cerebellum?
Q. 171. Medulla possesses centres for ?
Q. 172. How many pairs of spinal nerves arise from the spinal cord?
Q. 173. What is reflex arc?
Q. 174. What is autonomous nervous system?
Q. 175. Give two characteristics of hormones
Q. 176. Which organ controls the functioning of pituitary gland?
Q. 177. Which hormone maintains the ionic balance in the body?
Q. 178. What is the function of oxytocin?
Q. 179. What are the functions of estrogen and progesterone?
Q. 180. Which hormone regulates the male sex organs?
Q. 181. Which hormone acts as a growth promoter in plants?
Q. 182. What is the group of cells formed in multiple fission called?
Q. 183. Name two organisms reproducing by spore formation?
Q. 184. By which method do planaria and spirogyra reproduce?
Q. 185. Name two plants showing layering mode of vegetative propogation.
Q. 186. Which plants can be rafted on the stock of citrus?
Q. 187. Q. 1. What is the portion of the plant grafted on other plant called?
Q. 188. What is the temperature in the scortum?
Q. 189. Why is the ureter known as urinogenital path in case of males?
Q. 190. Which glands secrete semen?
Q. 191. What gives rise to an ovum in female?
Q. 192. What is ovulation in females?
Q. 193. is menopause?
Q. 194. What is copulation?
Q. 195. What is the function of amniotic fluid?
Q. 196. What is the zero method of natural contraception?
Q. 197. What do oral pills for contraception contain?
Q. 198. Name the organism causing Gonorrhoea.
Q. 199. Which scientists provided and evidence that gene is a part of chromosome?
Q. 200. What are prokaryotic chromosomes composed of ?
Q. 201. What is the length and diameter of each chromosome?
Q. 202. What is nucleolar organizer region?
Q. 203. Which purine nitrogen bases are present in the DNA molecule?
Q. 204. Which is the complimentary base pair of Cytosine?
Q. 205. What is the distance between each nucleotide pair in a DNA strand?
Q. 206. In which animal, the embryo develops into a female at high temperature?
Q. 207. What does the Recapitulation theory of Ernst Haeckel state?
Q. 208. Who is known as the Father of Taxonomy?
Q. 209. What is retrovirus? Give an example.
Q. 210. What is the extra chromosome found in male insects called?
Q. 211. How do CFC’s harm the atmosphere?
Q. 212. For what purpose are wet scrubbers used?
Q. 213. What is Eutrophication?
Q. 214. Why is the BOD of potable water less?
Q. 215. What is the full form of NEERI?
Q. 216. Define 1 A current.
Q. 217. What symbol is used in an electrical circuit to show inductor?
Q. 218. Comment on the voltage drop across a series connection.
Q. 219. Is it advisable to connect appliances in series connection domestically? Justify your answer.
Q. 220. 1 volt ampere is how many kW?
Q. 221. What is the nature and size of image formed by a convex lens when the object is at 2F?
Q. 222.What is the function of ciliary muscles?
Q. 223.Why is a voltmeter always connected in parallel in an electrical circuit?
Q. 224.A lamp of 100W glows for 2 hrs daily. Calculate the energy consumed in 30 days.
Q. 225. Define electroplating.
Q. 226. Name two addition and two condensation polymers.
Q. 227. What is the wavelength of visible light?
Q. 228. Where in Gujarat are wind farms located?
Q. 229. From which places is geothermal energy obtained in Gujarat?
Q. 230. What is the carbon content in anthracite?
Q. 231. Give two uses of Coke.
Q. 232. What gas is added in LPG cylinders to detect any leakage?
Q. 233. Which power station in Gujarat uses natural gas as a fuel?
Q. 234. What is the calorific value of hydrogen?
Q. 235. Which substances are used as coolants in nuclear reactors?
Q. 236. Name the moons of Saturn.
Q. 237. What are asteroids composed of?
Q. 238. How far is sun located from the galactic centre?
Q. 239. Which type of stars is found mostly in elliptical galaxies?
Q. 240. Give two properties of Rocket fuel.
Q. 241. What is the calorific vale of biogas?
Q. 242. Write the full form of GSLV.
Q. 243. Which satellite is used for weather forecasting?
Q. 244. What needs to be retrieved in Solvay’s ammonia soda process?
Q. 245. Which compound is used as an antacid?
Q. 246. Write the equation of the reaction taking place on inert anode in the electrolysis of molten NaCl.
Q. 247. Why is hydrogen used in welding metals?
Q. 248. At what temperature is rubber heated with sulphur to get vulcanized rubber?
Q. 249. What is the function of hepatic caecae found is digestive system of grasshopper?
Q. 250. During fission process what are the respective atomic masses of the elements obtained?
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