luni, 8 aprilie 2013

NITROGEN - ELEMENT CHEMISTRY, UTILITY OF NITROGEN

NITROGEN


Chemical Symbol: NAtomic Mass: 14Mass number "Z": 7Nitrogen is found in the fifth main group in the first period in the periodic table.
PHYSICAL:

Nitrogen is a case colorless, odorless, tasteless and non-toxic. It can be condensed into a colorless and then compressed into a colorless crystalline solid.Nitrogen has denistatea slightly less than air and is less soluble in water than oxygen. He maintains that living beings breathe.The melting temperature of the nitrogen is - 210, 01 ° C, while the boiling point of - 195 and 79 ° C.Natural state:
Nitrogen gas is one of the most widespread in nature. It is found both in the free state and complexed form:In the free state, nitrogen is 78% of the atmospheric air.Nitrogen compounds are:-Inorganic (ammonia, nitrates, etc.).-Organic (urea, proteins)Nitrogen found in a proportion of from 1 to 10% in each of the living organisms.CHEMICAL PROPERTIES: Nitrogen does not burn and does not support combustion. It shows a relatively low chemical reactivity.Reaction with oxygen:At temperatures above 3000 ° C, the nitrogen combines with oxygen to form nitrogen monoxide:N2 + O2 (2NO (reaction is reversible)Reaction with hydrogen:The temperature and pressure in the presence of a catalyst, nitrogen reacts with hydrogen, resulting ammonia:N2 + 3H2 (2NH3 (reaction is reversible)The main inorganic nitrogen compounds are:NH3HNO3NH4Cl (ammonium salts)(NH4) 2CO3 (baking powder)
Nitrogen cycle in nature:
Reduced activity of nitrogen allowed the use of an inert atmosphere increase. It represents the element protection from unwanted oxygen and energy shares.Higher plants and animals can not directly absorb nitrogen from the air. Plants extracted nitrogen that are needed by their roots, the soil, which contains ammonia or ammonium ions and nitrogen. Combination nitrogen plants are transferred grazing animals once their food.Combined nitrogen in plant and animal body returns to the ground after their death and decay during the decay occurring bacteria convert nitrogen combinations of proteins and other organic ammonia.In the lands cultivated by man, assimilable nitrogen extracted from plants is greater than that regenerate naturally. Because of this we need to add that soil nitrogen fertilizers.

UTILITY OF NITROGEN:Most of the nitrogen used in industry is distilled liquid air. This is then used to synthesise ammonia. Of ammonia produced in this way is get a wide variety of chemicals, including fertilizers, chemical fertilizers,etc..Another is the use of nitrogen in combination with oxygen, getting a medicine used anesthetic during surgery.A most recent application is the use of nitrogen in the field of cryogenics.Nitrogen is also used in dyes industry.
                                     HOW WAS DISCOVERED:
              
Even long after, when alchemist Helmont introduces the notion of gas, all gases were called, the air "with the addition that marked one of its properties. Van Helmont mentions but also one of the air components under the name, Sylvester gas ". It was carbon dioxide, and the name seems to come from imposibiliatea's condensation. Chemical study of the air starts to become a concern to researchers only in the second half of the eighteenth century. The first scientist who finds that air is not composed of one kind of substance is Joseph Black, an English chemist of French origin. Nitrogen occurs later, but not as distinct body, but confused with carbon dioxide. However, nitrogen is of Discovery and discoverer name is Daniel Rutherford. Who discovered nitrogen was a young Scotsman for 23 years, doing their thesis dissertation at the University of Edingburg to Professor John Black. Young chemist doing research on air, but in connection with plant respiration. In the course of numerous experiments have to prove that air "intertinea not burning is not only carbon dioxide but also nitrogen, which have many physical similarities. Thus D. Rutherford innrosit pass air over charcoal (charcoal) and combustion product washing with caustic alkali and lime water, which retains the carbon dioxide (passing the respective carbonates)., air "passing away, after the washing was Rutherford nitrogen that identifies it as a new body and called him, metific air "because not support life, considering it whatsoever, flawed" as the result by respiratie.Astfel Rutherford is recognized as the discoverer of nitrogen. Five years later (AL Lavoisier show that nitrogen exists in the free state in the atmosphere and it represents 79% of a volume of air. In 1789, when publisher first chemical nomenclature, A.Lavoisier (with Guyton of glanders) replaces the name of, mephitic air "and the, air flogisticat" with the nitrogen that comes from linking the two Greek words (a = privative and zoe = life) so lifeless because no animal life that it maintained inspire. In 1823, JA Chaptal (1756-1832), another French chemist, give nitrogen nitrogen name (after the Greek words = natron saltpeter and gennao = to produce), so producer of nitrate (saltpeter). nitrogen name remained particularly strong in France, and the nitrogen was taken in English-speaking countries.
                                        NATURALLY and METHODS of OBTAINING
                                                                  Nitrogen
           
It is very spread out nature that is found in the Earth's crust in the amount of 3x10-2%, it is also a main component of the air, which, as is known, consists of 78% (by volume) nitrogen free . The largest square in the earth's crust nitrogen is in the form of organic combinations, while combinations of inorganic nitrogen (except nitrate NaNO3) do not meet in large quantities in nature. Industrial methods of obtaining nitrogen nitrogen separation is based on the evaporation of liquid air oxygen in special instaltiilor. In laboratory conditions very pure nitrogen is obtained from combinations of, for example by passing ammonia over red hot copper oxide or ammonium nitrite NH4NO2 break down hot.
Physical properties:
   
Under ordinary conditions of temperature and Persians, nitrogen is a colorless, odorless and tasteless, a liter of nitrogen weighs 1.2506 g at high PERS strong cooling, nitrogen goes first in a colorless liquid boiling - 195.8 OC, and then into a solid that crystallizes in the cubic system and melts at -210.1 OC. The density of liquid nitrogen is 0.88 g/cm2. Nitrogen gas has a lower thermal conductivity than the liquid.
Chemical properties:
       
At low temperatures nitrogen is less active, in terms of making alloys nitrogen is an element that combines with metals and metalloids energrtic. More important are combinations of hydrogenated nitrogen amonacul primarily because its actions on certain metals or their oxides, nitrides form combinations that are obtained are stable at high temperatures and hot. Nitrogen and hydrogen. When passing an electrical discharge through a mixture of hydrogen and nitrogen to ammonia: N2 +3 H 2U2NH3, because this reaction is exothermic and is accompanied by a normal temperature release of 11.89 kcal / mol NH3 course by increasing the temperature will decrease the concentration of ammonia.
Nitrogen and phosphorus.       Phosphorus not combine the usual temperature, do not combine or by heating at 300oC in nitrogen phosphorus and ammonia. Rivets phosphorus - PN - forms the passage of electric sparks through the vapor of phosphorus and nitrogen. Metal rivets. Metal combinations with nitrogen formed by the action of nitrogen or ammonia. Lithium, magnesium, boron and aluminum, the type that reacts with oxygen in the air combines with nitrogen. Lithium, calcium, strontium, barium, magnesium, boron, aluminum, rare earths, silicon, titanium, zirconium, cerium, thorium, manganese combine directly with nitrogen by heating. On heating in ammonia form rivets: potassium, copper, barium, magnesium, zinc, aluminum titanium, manganese, iron.
Uses Nitrogen
         
Pure nitrogen is used in filling electric lamps. Combinations of nitrogen, the technique used is ammonia (NH3) which is used in motors cold, artificial ice getting in the manufacture of nitric acid and synthetic nitrogen fertilizer. Technique is of particular importance nitric acid (HNO3), widely used in chemical industry. Also used in the manufacture of dyes, medicines, getting explosives.

               
Nitrogen was captured for the first time in 1772 by British-born Dr Daniel Rutherford and officially recognized as one of the elementary gases around 1776 by French chemist Antoine Laurent Lavoisier