Information AboutNitrogen |
Nitrogen is a Chemical Element in the Periodic Table which has the symbol '''N''' and Atomic Number 7. Commonly a colorless, odorless, tasteless and mostly Inert Diatomic Non-metal gas, nitrogen constitutes 78.08% percent of Earth's Atmosphere and is a constituent of all living Tissue s. Nitrogen forms many important compounds such as Amino Acids , Ammonia , Nitric Acid , and Cyanide s. Notable characteristics Nitrogen is a Non-metal , with an Electronegativity of 3.0. It has five Electrons in its outer shell and is therefore Trivalent in most compounds. Pure nitrogen is an unreactive colorless Diatomic gas at standard room temperature, and comprises 78.08% of the Earth 's atmosphere. It Condenses at 77 K at Atmospheric Pressure and freezes at 63 K. Liquid nitrogen is a common Cryogen . Applications Nitrogen Compounds Molecular nitrogen in the atmosphere is relatively non-reactive, but in nature it is slowly converted into biologically (and industrially) useful compounds by some living organisms, notably certain Bacteria (i.e. Nitrogen Fixing Bacteria - see '' Biological Role '' below). The ability to combine or fix nitrogen is a key feature of modern industrial chemistry, where nitrogen and Natural Gas are converted into Ammonia via the Haber Process . Ammonia, in turn, can be used directly (primarily as a Fertilizer ), or as a precursor of many other important materials including Explosives , largely via the production of Nitric Acid by the Ostwald Process . The Salt s of nitric acid include important compounds such as Potassium Nitrate (or Saltpeter , important historically for its use in Gunpowder ) and Ammonium Nitrate , an important fertilizer. Various other nitrated organic compounds, such as Nitroglycerin and Trinitrotoluene , are used as explosives. Nitric acid is used as an Oxidizing Agent in liquid fueled Rocket s. Hydrazine and hydrazine derivatives find use as rocket Fuel s. Molecular nitrogen (gas and liquid) Nitrogen gas, N2, is produced by allowing liquid nitrogen, N2(''l'') (see below) to warm and Evaporate . It has a wide variety of applications, including serving as a more Inert replacement for air where Oxidation is undesirable;
Contrary to some claims, nitrogen does not Diffuse through tire Rubber more slowly than air. Air is mostly a Mixture of nitrogen and oxygen (as N2 and O2), and the nitrogen molecules are ''smaller''. All else being equal, smaller molecules diffuse through porous substances more ''quickly''. A further example of its versatility is its use as a preferred alternative to Carbon Dioxide to pressurize kegs of some Beer s, particularly thicker Stouts and Scottish and English Ale s, due to the smaller bubbles it produces, which make the dispensed beer smoother and headier. A modern application of a pressure sensitive nitrogen capsule known commonly as a " Widget " now allows nitrogen charged beers to be packaged in cans and bottles. (for storing laboratory samples at a temperature of about -150 Celsius).]] Liquid nitrogen is produced industrially in large quantities by Distillation from Liquid Air and is often referred to by the quasi-formula '''LN2''' (but is more accurately written '''N2(''l'')''' ). It is a Cryogenic (extremely cold) fluid which can cause instant Frostbite on direct contact with living tissue. When appropriately Insulated from ambient Heat it serves as a compact and readily transported source of nitrogen gas without pressurization. Further, its ability to maintain temperatures far below the Freezing Point of water as it evaporates (77 K , -196 ° C or -320 ° F ) makes it extremely useful in a wide range of applications as an open-cycle Refrigerant , including;
History Nitrogen ( Latin ''nitrum'', Greek ''Nitron'' meaning "native soda", "genes", "forming") is formally considered to have been discovered by Daniel Rutherford in 1772 , who called it ''noxious air'' or ''fixed air''. That there was a fraction of air that did not support Combustion was well known to the late 18th century chemist. Nitrogen was also studied at about the same time by Carl Wilhelm Scheele , Henry Cavendish , and Joseph Priestley , who referred to it as ''burnt air'' or ''phlogisticated air''. Nitrogen gas was Inert enough that Antoine Lavoisier referred to it as ''azote'', from the Greek word αζωτος meaning "lifeless". This term has become the French word for "nitrogen" and later spread out to many other languages. Compounds of nitrogen were known in the Middle Ages . The Alchemists knew Nitric Acid as ''aqua fortis''. The mixture of nitric and Hydrochloric Acid s was known as '' Aqua Regia '', celebrated for its ability to dissolve Gold . The earliest industrial and Agricultural applications of nitrogen compounds used it in the form of Saltpeter ( Sodium- or Potassium Nitrate ), notably in Gunpowder , and much later, as Fertilizer , and later still, as a chemical Feedstock . Occurrence Nitrogen is the largest single component of the Earth's Atmosphere (78.084% by volume, 75.5% by weight) and is acquired for industrial purposes by the fractional Distillation of liquid air or by mechanical means of gaseous air (i.e. pressurised reverse Osmosis Membrane or pressure swing adsorption). Compounds that contain this element have been observed in Outer Space . 14Nitrogen is created as part of the Fusion processes in Star s. Nitrogen is a large component of animal waste (for example, Guano ), usually in the form of Urea , Uric Acid , and compounds of these nitrogenous products. Molecular nitrogen is a constituent of Titan 's atmosphere and has been detected in Interstellar Space by David Knauth and coworkers using the Far Ultraviolet Spectroscopic Explorer . ''See also .'' Compounds The main neutral Hydride of nitrogen is Ammonia (N H 3) although Hydrazine (N2H4) commonly used. Ammonia is more Basic than Water by 6 orders of magnitude. In Solution ammonia forms the Ammonium Ion (NH4+). Liquid ammonia (b.p. 240 K) is Amphiprotic (displaying either Brønsted-Lowry acidic or basic character) and forms ammonium and less commonly) Amide ions (NH2-); both amides and Nitride (N3-) Salt s are known, but Decompose in water. Singly, doubly and triply substituted alkyl compounds of ammonia are called Amine s. Larger chains, rings and structures of nitrogen hydrides are also known but are generally unstable. Other classes of nitrogen Anion s (negatively charged ions) are Azide s (N3-), which are linear and Isoelectronic to Carbon Dioxide . Another Molecule of the same structure is Dinitrogen Monoxide (N2 O ), also know as laughing gas. This is one of a variety of Oxide s, the most prominent of which are Nitrogen Monoxide (NO) and Nitrogen Dioxide (NO2), which both contain an unpaired Electron . The latter shows some tendency to Dimerize and is an important component of Smog . The more standard oxides, Dinitrogen Trioxide (N2O3) and Dinitrogen Pentoxide (N2O5), are actually fairly unstable and explosive. The corresponding acids are Nitrous (HNO2) and Nitric Acid (HNO3), with the corresponding salts called Nitrite s and Nitrate s. Nitric acid is one of the few acids stronger than Hydronium , and is a fairly strong Oxidizing Agent . Nitrogen can also be found in , Amides , Nitro groups, Imine s, and Enamine s. ''See also .'' Biological role Nitrogen is an essential part of Amino Acid and Nucleic Acid s both of which are essential to life. Certain types of bacterium (e.g. Rhizobium ''trifolium'') possess Nitrogenase enzymes which can fix atmospheric nitrogen into a form (ammonium) that is chemically useful to higher organisms. This process requires a large amount of energy. Such bacteria may be free in the soil (e.g. azotobacter) but normally exist in a symbiotic relationship in the root nodules of leguminous plants (e.g. clover or the soya bean plant). The conversion of atmospheric nitrogen to biologically useful nitrogen is called Nitrogen Fixation . The leguminous plant subsequently converts the ammonium to nitrogen oxides and amino acids to form Protein s and other biologically useful molecules. In return, the plant secretes sugars to the symbiotic bacteria. Other plants can assimilate nitrogen in the form of nitrates. Nitrates are converted to nitrites by the enzyme nitrate reductase, and then converted to ammonia by another enzyme called nitrite reductase. Isotopes There are two stable in Star s and the remaining is 15N. Of the ten isotopes produced synthetically, 13N has a Half Life of nine minutes and the remaining isotopes have half lives on the order of seconds or less. Biologically-mediated reactions (e.g., Assimilation , Nitrification , and Denitrification ) strongly control nitrogen dynamics in the soil. These reactions almost always result in 15N enrichment of the Substrate and depletion of the Product . Although Precipitation often contains subequal quantities of Ammonium and nitrate, because ammonium is preferentially retained by the canopy relative to atmospheric nitrate, most of the atmospheric nitrogen that reaches the soil surface is in the form of nitrate. Soil nitrate is preferentially assimilated by tree roots relative to soil ammonium. Precautions Rapid release of nitrogen gas into an enclosed space can displace oxygen, and therefore represents an asphixiation hazard. Nitrogen also dissolves in the Bloodstream , and rapid decompression (particularly in the case of divers ascending too rapidly) can lead to a potentially fatal condition called Decompression Sickness , when nitrogen bubbles form in the bloodstream. It can also cause Nitrogen Narcosis . See also References
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