Nitrogen
Chemical formula | N |
---|---|
Atomic Number | 7 |
OTP appearance | colorless gas |
Molar Mass(g/mol) | 14 |
Density(g/cc) | 0.00125 |
Melting Point(°C) | -210 |
Boiling Point(°C) | -195.8 |
Solubility in water(g/L) | 0.02 |
Speed of sound 20°C, 1atm (m/s) |
349 |
NFPA 704 |
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
- Combine (as dried solids) sodium nitrate and charcoal
- Heat until molten and charcoal ignites
- 4 NaNO3 + 5 C → 2 Na2CO3 + 3 CO2 + 2 N2
- Lead resultant gases through a solution of sodium hydroxide or calcium hydroxide
- N2(g) + CO2(g) + 2 NaOH(aq) → Na2CO3(aq) + H2O + N2(g)
- 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)