Nitrogen is one of the most abundant elements on Earth - in the atmosphere its content exceeds 78%. The existence of such a large amount of nitrogen in a free state indicates its inertness and difficult interaction with other elements under ordinary conditions.
In a bound state, this substance can be found in organic and inorganic matter. Bound to carbon and oxygen, nitrogen is found in animal and plant proteins.
The name "nitrogen" itself was invented by Lavoisier, who, in the course of numerous experiments, established the presence of some inert substance in the atmosphere. The scientist considered this substance lifeless - in Greek, "azote".
Nitrogen cycle
Despite the inertness of nitrogen, in nature there are constant processes of its fixation or binding. For example, in the roots of legumes, special bacteria accumulate that fix nitrogen, processing it into nitrates.
In the atmosphere, this gas is oxidized during the discharge of lightning. Then, nitrogen oxides dissolve in the precipitate, forming nitric acid and nitrous acid . With snow, rain, fog, nitrogen enters the soil, where it turns into nitrites or nitrates. Then various plants use them to build protein. Animals feed on plants, and plant protein is processed into animal. When plants and animals decompose after death, all nitrogen compounds in their organisms turn into ammonia. Bacteria destroy it to the simplest elements, releasing pure nitrogen and hydrogen again. This is how the nitrogen cycle or nitrogen cycle occurs in nature.
Chemical properties of nitrogen
Under normal conditions, its main property is inertia, i.e. minimal chemical activity. The nitrogen atom can form a bond with another nitrogen atom, which is quite unusual for chemical elements (with the exception of silicon and carbon).
When heated, this element reacts with most metals. In this case, ionic, covalent or intermediate nitrides with a negatively charged nitrogen ion are formed.
In a reaction with hydrogen, nitrogen forms fairly stable compounds - nitrogen hydrogen, which vaguely resembles hydrocarbons. Such substances include ammonia, hydrazine and nitric acid.
Production and use of nitrogen
Compounds of this substance play an important role in industry and agriculture. The method of producing nitrogen in the form of a chemical element depends on the required degree of purity. Most nitrogen is needed for the production of ammonia, but an insignificant content of noble gases is allowed.
Obtaining nitrogen from the atmosphere
This is one of the most economical methods in which the purified air is subsequently liquefied by cooling and expansion. The resulting liquid air is distilled through fractions, while slowly raising the temperature. In this process, noble gases are first released, and then nitrogen. Only liquid oxygen remains .
This nitrogen production allows many millions of tons of this substance to be produced every year. Nitrogen is used mainly for the subsequent production of ammonia, which, in turn, acts as a raw material for the production of industrial and agricultural nitrogen-containing compounds.
Pure nitrogen atmosphere can also be used when a complete lack of oxygen is needed.
Obtaining nitrogen in the laboratory
In small quantities, this gas is obtained by oxidizing ammonium ions or ammonia. In particular, the ammonium ion can be oxidized with a nitrite ion.
Nitrogen production during decomposition
When heated, azides decompose, ammonia decomposes by copper oxide, nitrites decompose by reaction with urea or sulfamic acid - as a result of all these reactions, nitrogen is formed.