Nitrogen

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Nitrogen
Chemical formula N
Atomic Number
OTP appearance colorless gas 
Molar Mass(g/mol) 14 
Melting Point(°C) -210 
Boiling Point(°C) -195.8 
Density(g/cc) 0.00125 
Solubility in water(g/L) 0.02 
Speed of sound
20°C, 1atm (m/s)
349
NFPA 704
NFPA704.png
0
3
0
 

Under normal circumstances Nitrogen is a fairly inert gas (N2). It is the primary constituent of air.

Ecological nitrogen cycle

Gaseous nitrogen (N2) is cleaved by nitrogenase (usually found in single-celled organisms called Diazotrophs) and integrated into the organism's metabolism, usually reentering the ecosystem as ammonia when the organism dies or excretes. Ammonia is absorbed by water and becomes ammonium ions. Ammonium ions are consumed by Nitrosomonas (and others) which convert ammonium ions to nitrite ligands, which are oxidized to nitrates by Nitrobacter (and others). These nitrates can be chemically isolated when bonded to alkali metals.

Ammonia Production
Actor Source Nitroform Chemistry Resultant Nitroform Timeframe
Nitrogenase in the Diazotroph Atmospheric N2 2 N2 + 6 H2O 4 NH3 + 3 O2 Ammonia Continuously
Urease in bacteria and fungi Urea (NH2)2CO + H2O CO2 + 2 NH3 Ammonia "a few days"
Nitrate production
Water Ammonia NH3 + H2O NH4- + OH +  Ammonium ions Immediately
Nitrosomonas Ammonium ions NH4- + 2 O2 NO2- + 2 H2O Nitrites "a few weeks"
Nitrobacter Nitrites 2 NO2- + O2 NO3- Nitrates

Uses

Primary

  • As an inert gas
  • As a source of ammonia via the haber process

Natural occurrence

  • As gaseuous N2 in air
  • As a component of urea (CO(NH2)2) in animal waste
  • As a component of ammonia (NH3) in decomposed organic waste

Hazards

  • Nitrogen asphyxia

Production

Extraction

  • from air. See air for separation of nitrogen from air.

Synthesis

sodium nitrate

  1. Combine (as dried solids) sodium nitrate and charcoal
  2. Heat until molten and charcoal ignites
    4 NaNO3 + 5 C 2 Na2CO3 + 3 CO2 + 2 N2
  3. Lead resultant gases through a solution of sodium hydroxide or calcium hydroxide
    N2(g) + CO2(g) + 2 NaOH(aq) Na2CO3(aq) + H2O + N2(g)
  4. Recover the nitrogen gas emerging from the solution.

sodium nitrite

Combine ammonium chloride and sodium nitrite, producing ammonium nitrite and salt. The ammonium nitrite decomposes into nitrogen and water.

NH4Cl + NaNO2 NH4NO2 + NaCl
NH4NO2 N2(g) + 2 H2O(l)

Purification

Testing

Storage

Disposal

See Also

References