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Ammonia

General information about ammonia

Molecule of ammonia (NH3) consists of one atom of Nitrogen (N) and three atoms of Hydrogen (H).The atoms in the molecule of ammonia are arranged in a form of a trigonal pyramid with the atom of nitrogen at the vertex. This arrangement determines high dipole moment of the molecule. Some chemical properties of ammonia (e.g. solubility in water) are explained by the polarity of its molecule.

Ammonia was first synthesized in 1774 by Joseph Priestley.
Molecular weight of ammonia is 17.03.
Gaseous ammonia is lighter than air therefore it does not pool indoors.
Ammonia has sharp pungent odor.

Ammonia forms alkaline solution in water (ammonium hydroxide):

NH3 + H2O = NH4OH

Gaseous ammonia may be easily transformed to liquid state either by cooling below the boiling point -28.03°F (-33.35°C) or by compression.

Vapor pressure of ammonia is 114 psi (786 kPa).

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Manufacture of ammonia

Ammonia is produced by the reaction between nitrogen and hydrogen in the presence of iron oxides as a catalyst (Haber-Bosch process):

N2 + 3H2 = 2NH3
The process achieves maximal productivity at temperatures in the range 750 - 1100°F (399 - 593°C) and at pressures in the range 200 - 400 atm.

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Applications of ammonia

  • Most of ammonia is used for manufacturing soil fertilizers in form of ammonium nitrate, ammonium phosphate and urea.
  • Manufacture of polymeric fibers from polyamides (nylons) and acrylics.
  • Fabrication of nitric acid by Ostwald process (oxidation of ammonia in the presence of platinum as a catalyst followed by dissolution of the resulting nitrogen oxide in water). Nitric acid is widely used for manufacturing explosives (nitroglycerine).
  • Household cleaners like wax removers, toilet cleaners, window cleaners contain up to 10% of ammonia.
  • Dyeing and scouring of cotton, silk, wool.
  • Source of hydrogen for the processes conducted in reducing atmosphere (Sintering of metals, heat treatment of metals) or as a fuel (Oxyhydrogen welding (OHW)).
  • Hardening of steel parts by nitriding.

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Health effects of ammonia

  • Ammonia is extremely dangerous corrosive material, water solutions of which may cause severe irritation or full thickness burns.
  • Inhaling ammonia may cause headache, nausea, vomiting, fainting or even death.
  • Swallowing ammonia can cause severe burns of the mouth, throat, and stomach, leading to death. Eye exposure may result in redness, pain, temporary or permanent blindness.
  • Prolonged or repeated skin exposure may cause eye, liver, kidney, or lung damage and dermatitis.

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Properties of ammonia

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ammonia.txt · Last modified: 2012/06/02 by dmitri_kopeliovich
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