This content from Wikipedia is licensed under the GNU Free Documentation License.
HOME - Help build the worlds largest free encyclopedia.
Nitrogen
Nitrogen is a chemical Carbon - Nitrogen - Oxygen element in the periodic table that has the symbol Ê N and atomic number 7. A N common normally PÊÊ colorless, odorless, tasteless and mostly Ê inert diatomic non-metal General gas, nitrogen constitutes 78 percent of earth's Name, Symbol, Number Nitrogen, N, 7 atmosphere and is a Chemical series nonmetals constituent of all living Group, Period, Block 15 (VA), 2 , p tissues. Nitrogen forms many important compounds Density, Hardness 1.2506 kg/m3(273K), NA such as ammonia, nitric acid, and cyanides. Appearance colorless Atomic Properties Atomic weight 14.0067 amu Atomic radius (calc.) 65 (56) pm Covalent radius 75 pm van der Waals radius 155 pm Electron configuration [He]2s22p3 e- 's per energy level 2, 5 Oxidation states (Oxide) ±3,5,4,2 (strong acid) Crystal structure hexagonal Notable Characteristics Physical Properties State of matter gas (__) Nitrogen is a non-metal, with an electronegativity Melting point 63.14 K (-345.75 ¡F) of 3.0. It has five Boiling point 77.35 K (-320.17 ¡F) electrons in its outer shell, so is trivalent in Molar volume 13.54 ×10-3 m3/mol most compounds. Pure Heat of vaporization 2.7928 kJ/mol nitrogen is an unreactive Heat of fusion 0.3604 kJ/mol colorless diatomic gas at room temperature, and Vapor pressure __ Pa at __ K comprises about 78% of Speed of sound 334 m/s at 298.15 K the Earth's atmosphere. It condenses at 77 K and Miscellaneous freezes at 63 K. Liquid Electronegativity 3.04 (Pauling scale) nitrogen is a common Specific heat capacity 1040 J/(kg*K) cryogen. Electrical conductivity __ 106/m ohm Applications Thermal conductivity 0.02598 W/(m*K) The greatest single 1st ionization potential 1402.3 kJ/mol commercial use of 2nd ionization potential 2856 kJ/mol nitrogen is as a component in the 3rd ionization potential 4578.1 kJ/mol manufacture of ammonia via the Haber process. 4th ionization potential 7475.0 kJ/mol Ammonia is subsequently 5th ionization potential 9444.9 kJ/mol used for fertilizer production and to produce 6th ionization potential 53266.6 kJ/mol nitric acid. Nitrogen is 7th ionization potential 64360 kJ/mol used as an inert atmosphere in tanks of Most Stable Isotopes explosive liquid storage tanks, during production iso NA half-life DM DE MeV DP of electronic parts such 13N {syn.} 9.965 m e capture 2.220 13C as transistors, diodes, and integrated circuits, 14N 99.634% N is stable with 7 neutrons and is used in the 15N 0.366% N is stable with 8 neutrons manufacture of stainless steel. Nitrogen is used SI units & STP are used except where noted. as a coolant both for the immersion freezing of food products and for transportation of foods, for the preservation of bodies and reproductive cells (sperm and egg), and for the stable storage of biological samples in biology. The salts of nitric acid include some important compounds, for example potassium nitrate, or saltpeter, and ammonium nitrate. The former compound is a component of gunpowder, the latter important in fertilizer. Nitrated organic compounds, such as nitroglycerin and trinitrotoluene, are often explosives. Nitric acid is used as an oxidizer in liquid fueled rockets. Hydrazine and hydrazine derivatives find use as rocket fuels. Nitrogen in its liquid state (often referred to as LN2) is often used in cryogenics. Liquid nitrogen is produced by distillation from liquid air. At atmospheric pressure, nitrogen condenses at -195.8 degrees Celsius. (-320.4 degrees Fahrenheit). 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. 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 dephilogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as azote, which stands for without life. Compounds of nitrogen were known in the Middle Ages. The alchemists knew nitric acid as aqua fortis. The mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold. Occurrence Nitrogen is the largest single component of the Earth's atmosphere (78.1% by volume) and is acquired for industrial purposes by the fractional distillation of liquid air.. Compounds that contain this element have been observed in outer space. Nitrogen-14 is created as part of the fusion processes in stars. 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. Compounds The main hydride of nitrogen is ammonia (NH3) although hydrazine (N2H4) is also well known. Ammonia is somewhat more basic than water, and in solution forms ammonium ions (NH4+). Liquid ammonia in fact slightly amphiprotic and forms ammonium and amide ions (NH2-); both amides and nitride (N3-) salts are known, but decompose in water. Singly and doubly substituted compounds of ammonia are called amines. Larger chains, rings and structures of nitogen hydrides are also known but virtually unstable. Other classes of nitrogen anions are azides (N3-), which are linear and isoelectronic to carbon dioxide. Another molecule of the same structure is dinitrogen monoxide (N2O), or laughing gas. This is one of a variety of oxides, 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 nitrites and nitrates. Nitric acid is one of the few acids stronger than hydronium. Biological Role Nitrogen is an essential part of amino and nucleic acids which makes nitrogen vital to all life. Legumes like the soybean plant, can recover nitrogen directly from the atmosphere because their roots have nodules harboring microbes that do the actual conversion to ammonia in a process known as nitrogen fixation. The legume subsequently converts ammonia to nitrogen oxides and amino acids to form proteins. Isotopes There are two stable isotopes: N-14 and N-15. By far the most common is N-14 (99.634%), which is produced in the CNO cycle in stars. The rest is N-15. Of the ten isotopes produced synthetically, one 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 N-15 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 Nitrate fertilizer washoff is a major source of ground water and river pollution. Cyano (-CN) containing compounds form extremely poisonous salts and are deadly to many animals and all mammals.
How to - Physics - History - Companies - Internet - Video Games - List of Phobias - September 11, 2001
Radio - Timelines - Chemistry - Genealogy - Family - Film - SARS - Cancer - Medicine - DVD - Calendar
Countries - Disease - Health Science - Dentistry - Economics - AIDS - Law - Autism - Statistics - Bible
Recipes - Architecture - Computers - History of the Internet - Personal computer - Apple Macintosh
War - Presidents of the United States - United States Constitution - Universe - Philosophy - Animals
Biology - United States Constitution - Marketing Topics - Sports - Television - History of Computing
This content from Wikipedia is licensed under the GNU Free Documentation License.
HOME - Help build the worlds largest free encyclopedia.
