Nitrogen

Nitrogen is chemically inactive, which gives it several uses.   The electronics industry uses nitrogen as a blanket against pollutants in the production of semiconductors, such as transistors and diodes.   Nitrogen also is used to anneal stainless steel and other steel products.   It is used for production of resins, dyes, adhesives, and pharmaceuticals.   Nitrogen is used to produce nitric acid, which is used for the production of fibers, resins, and polymers.   Nitrogen is used as a refrigerant for immersion freezing of foods and food transportation.   Liquid nitrogen is used as a component purge and insulator for space chambers.   Nitrogen at great pressures is used in petroleum drilling to force petroleum to the surface.   Its compounds are very active and used in extensively in foods, fungicides, defoliants, fertilizers and explosives.   The ammonia industry is the largest user of nitrogen.   Nitrogen is heated under pressure with hydrogen and a catalyst to produce ammonia, NH₃, an important fertilizer, by the Haber process.   When oxidized, ammonia becomes nitric acid by the Oswald process.

Important nitrogen compounds are the following:

Ammonia is used in agriculture as a fertilizer, livestock protein, pre-harvest cotton defoliant, fungicide on some fruits, and a high-moisture corn preservative while in storage.

Nitric acid, HNO₃, is used to make fertilizers, the explosive trinitrotoluene (TNT), and other industrial chemicals.

Nitrogen oxides, such as, nitric oxide, NO, and nitrogen dioxide, NO₂, are formed in vehicle exhaust when a spark from gasoline engines unites nitrogen with oxygen from the air.   When the oxides combine with air moisture, they form nitric acid that is harmful to plants and animals when it falls to earth.   These chemical reactions make vehicle exhaust a major pollutant.

Nitrates: Calcium nitrate (fertilizer, diesel fuel corrosion inhibitor), cobalt nitrate (a catalyst), magnesium nitrate (fertilizers, explosives) and manganese nitrate (colour agent in porcelain and ceramics, a catalyst in the production of manganese dioxide). ^{Lide 4-20}

Nitrogen is essential to life because it is a part of all animal and plant nucleic acids (e.g., DNA and RNA) and proteins.   However, excessive phosphorus from fertilizers and detergents that leach into freshwater lakes and rivers limit acquatic animal life by causing excessive plant and algae growth and death, during which decomposing bacteria use up the oxygen gas dissolved in the water, making it unavailable to acquatic animals.   This process is called eutrophication.

Nitrogen is a major component of proteins, hormones, chlorophyll, vitamins and enzymes in plants.   Nitrogen metabolism occurs in stem and leaf growth.   However, too much nitrogen can delay flowering and fruiting.   A deficiency reduces yields, causes yellowing of the leaves and stunts growth. ^{Morgan n.p.}   Because nitrogen compounds are ingested by plants, they are often depleted from the soil and must be replaced by fertilizers.

Nitrogen was discovered in 1772 by Daniel Rutherford, a British chemist.   Nitrogen makes up about 78% of the air by volume from which it is extracted by liquification and fractional distillation.   It also can be prepared by heating a water solution of ammonium nitrite. ^{Lide 4-19}