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Nitrogen compounds for rocket fuels.
(L. nitrum, Gr. Nitron, native soda; genes, forming) Nitrogen was
discovered by chemist and physician Daniel Rutherford in 1772. He removed oxygen and
carbon dioxide from air and showed that the residual gas would not support combustion or
living organisms. At the same time there were other noted scientists working on the
problem of nitrogen. These included Scheele, Cavendish, Priestley, and others. They called
it burnt or dephlogisticated air, which meant air without oxygen.
Nitrogen gas (N2) makes up 78.1% of the Earths air, by volume.
The atmosphere of Mars, by comparison, is only 2.6% nitrogen. From an exhaustible source
in our atmosphere, nitrogen gas can be obtained by liquefaction and fractional
distillation. Nitrogen is found in all living systems as part of the makeup of biological
The French chemist Antoine Laurent Lavoisier named nitrogen azote, meaning without
life. However, nitrogen compounds are found in foods, fertilizers, poisons, and
explosives. Nitrogen, as a gas is colorless, odorless, and generally considered an inert
element. As a liquid (boiling point = minus 195.8oC), it is also colorless and
odorless, and is similar in appearance to water. Nitrogen gas can be prepared by heating a
water solution of ammonium nitrite (NH4NO3).
Nitrogen Compounds and Nitrogen in Nature
Sodium nitrate (NaNO3) and potassium nitrate (KNO3) are
formed by the decomposition of organic matter with compounds of these metals present. In
certain dry areas of the world these saltpeters are found in quantity and are used as
fertilizers. Other inorganic nitrogen compounds are nitric acid (HNO3), ammonia
(NH3), the oxides (NO, NO2, N2O4, N2O),
cyanides (CN-), etc.
The nitrogen cycle is one of the most important processes in nature for living
organisms. Although nitrogen gas is relatively inert, bacteria in the soil are capable of
fixing the nitrogen into a usable form (as a fertilizer) for plants. In other
words, Nature has provided a method to produce nitrogen for plants to grow. Animals eat
the plant material where the nitrogen has been incorporated into their system, primarily
as protein. The cycle is completed when other bacterial convert the waste nitrogen
compounds back to nitrogen gas. Nitrogen has become crucial to life being a component of
Ammonia (NH3) is the most important commercial compound of nitrogen. It
is produced by the Haber Process. Natural gas (methane, CH4) is reacted with
steam to produce carbon dioxide and hydrogen gas (H2) in a two step process.
Hydrogen gas and nitrogen gas are then reacted in 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 also used in the production of urea, NH2CONH2,
which is used as a fertilizer, in the plastic industry, and in the livestock industry as a
feed supplement. Ammonia is often the starting compound for many other nitrogen compounds.
Sources: CRC Handbook of Chemistry
and Physics and the American Chemical Society.
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