Facts About Nitrogen

Atomic Number: 7
Atomic Weight: 14.0067
Atomic Symbol: N
Melting Point: -321 F (-210 C)
Boiling Point: -320.42 F (-195.79 C)

Word origin: A combination of the Greek nitron, meaning native soda, and genes, meaning forming. It also has roots in the Latin word nitrum.

Discovery: Chemist and physician Daniel Rutherford discovered nitrogen in 1772 when he removed oxygen and carbon dioxide from air and demonstrated that the residual gas would not support living organisms or combustion. Other scientists, including Carl Wilhelm Scheele and Joseph Priestly, were working on the problem at the same time, calling it "burnt" air, or air without oxygen.

Properties of nitrogen

Because nitrogen is a component of all proteins, it is crucial to life. Nitrogen is found in all living systems as part of the composition of biological compounds.

Nitrogen has the appearance of water as a liquid at the boiling point, as it is also colorless and odorless. It is generally considered an inert element. [See Periodic Table of the Elements]

When a water solution of ammonium nitrite is heated, it forms nitrogen gas.

Liquid nitrogen
Liquid nitrogen boils at room termperature.
Credit: David Monniaux

Sodium nitrate and potassium nitrate are formed when organic matter containing compounds of these metals decompose. Other inorganic nitrogen compounds include nitric acid, ammonia, the oxides and cyanides.

Sources of nitrogen

Nitrogen compounds are found in foods, organic materials, fertilizers, explosives and poisons.

Nitrogen gas makes up 78.1 percent of Earth’s air, by volume, compared to Mars, which is only 2.6 percent nitrogen. Nitrogen gas can be obtained by liquefaction and fractional distillation, and there is an inexhaustible supply in our atmosphere.

The nitrogen cycle is one of the most crucial natural processes necessary to sustain life.  While nitrogen gas is relatively inert, bacteria in the soil employ a method to produce nitrogen for plants to grow. Animals eat the plant material where the nitrogen has been incorporated into their system, primarily and complete the cycle when other bacteria convert the waste nitrogen compounds back to nitrogen gas.

Uses of nitrogen

Ammonia is the most important commercial compound of nitrogen. Natural gas (methane) is reacted with steam to produce carbon dioxide and hydrogen gas in a two-step process. Hydrogen gas and nitrogen are combined in a method called the Haber process to produce ammonia. This colorless gas with a pungent odor is easily liquefied (in fact, the liquid is used as a nitrogen fertilizer).

Ammonia is often the starting compound for many other nitrogen compounds, is also used in the production of urea, which is used as a fertilizer, in the plastic industry, and as a feed supplement in used in the livestock industry.

Because it boils at minus 195.8 C (minus 321 F), nitrogen is often used for cooling. When in its liquid state, nitrogen is often stored in large thermos-like containers called "dewars."

(Source: Los Alamos National Laboratory)

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