of nitrogen (nitrogen) has a few connections to the hydrogenic (hydrogen), of which the most weighty importance ammonia.In the laboratory it is prepared by heating a mixture of ammonium chloride with potassium hydroxide.Until the late 19th century, the Chilean deposit of sodium nitrate was considered the only source of nitrogen compounds.Thanks to scientific research, chemists have been proposed several methods of fixation of atmospheric Nitrogen.The first of these was the cyanamide ammonia synthesis process.This method is based on the ability to connect with urea nitrogen calcium.To do this, nitrogen is passed through a heated calcium carbide:
N2 + CaC2 = CaCN2 + C
thus obtained CaCN2 (calcium cyanide) is used as a nitrogen fertilizer in agriculture.It should be noted that the treatment of the compound with water vapor to produce ammonia:
CaCN2 + ZN20 = 2NH3 + CaC03
processed ammonia nitrate acid and nitrogen fertilizers.In modern chemistry is widespread other method of obtaining NH3 - his syn
1/2 N +3/2 H2 = NH3
thus obtained is called synthetic ammonia.Industrial synthesis of ammonia produced in the presence of a catalyst and at a temperature of 500 degrees.
ammonia - a gas which has a pungent characteristic odor, it is lighter than air.You can not breathe NH3 long time because it is toxic.This gas is rather easily soluble in H2O.Concentrated aqueous ammonia containing 25% NH3.
When cooled (to -79 ° C) solution of aqueous ammonia becomes crystalline.Scientific studies have proven that the majority of NH3 in aqueous solution is in the form of hydrated molecules (NH3 · nH2O) and only a small portion of the dissolved ammonia (about 0.5%) is reacted with water:
NH3 + H2O = NH4 + + OH -
alkaline reaction of ammonia solutions due to the presence of hydroxide ions.Traditionally ammonia solution is designated as NH4OH.The alkalinity of the solution caused by the presence of a hydroxyl group, which is formed as a result of dissociation of ammonium hydroxide.
ammonia solution is considered a weak base.In laboratories sometimes ammonia is produced by heating ammonium chloride.Ammonia is quite active chemical compound that reacts with many substances, thus showing only reducing properties.
Ammonia burns, with oxygen in the presence of greenish-yellow flame, while being oxidized to a free of nitrogen.In the presence of a catalyst (platinum), the oxidation of ammonia · goes on to form the oxide of nitrogen.This reaction is used in the preparation of nitrate acid.It should be noted that most of the thus obtained ammonia consumed in the production of nitrate fertilizers and nitric acid.
During evaporation at -33,4 ° C, liquid NH3 from the environment absorbs a lot of heat causes cooling.This property it is used in refrigeration systems for artificial ice when storing perishable foods.Often the liquid ammonia is used in the construction of underground structures.The ammonia solution is used in laboratory practice, the chemical industry, household goods, and in medicine.
ammonia solution application.Applied as a means to drive the patient breathing and excretion of syncope.Large concentrations of NH3 can cause respiratory arrest.Sometimes ammonia solution is used as emetics (10 drops per 100 ml water).Note that it is a pharmaceutical agent can not be applied topically in the presence of skin diseases (eczema, dermatitis).When ammonia vapor poisoning physicians prescribe acetate, citrate, tartrate (tartaric acid) at 1% concentration.In surgical practice using an ammonia solution (25 ml / 5 liter of boiled, hot water).