Ammonia
Overview
Ammonia (uh-MOH-nyah) is a colorless gas with a strong, suffocating odor. It was present in the primordial (original) atmosphere of the Earth. Scientists believe that it may have been the source of nitrogen for the earliest forms of life. Ammonia was the first chemical compound to be found in interstellar space, the space between stars. It is a major component of the atmosphere of many planets in our solar system.
Early chemists learned to produce ammonia from animal parts, such as the horns of deer. But it was the English chemist and physicist Joseph Priestley (1733–1804) who first collected and studied the pure gas. In 1785, the French chemist Claude-Louis Berthollet (1748–1822) determined the correct chemical formula for the gas, NH3.
Key Facts
Other Names:
None
Formula:
NH3
Elements:
Nitrogen, hydrogen
Compound Type:
Inorganic base
State:
Gas
Molecular Weight:
17.03 g/mol
Melting Point:
−77.7°C (−108°F)
Boiling Point:
−33.35°C (−28.03°F)
Solubility:
Very soluble in cold water; soluble in alcohol, ether, and many organic solvents
In 2004, American companies produced 10,762,000 metric tons (11,863,000 short tons) of ammonia, making it the tenth highest-volume chemical made in the United States. Only ten years earlier, it had ranked number 5 on the list of all chemicals produced by volume. About 90 percent of all the ammonia used in the United States goes to the production of fertilizers.
How It Is Made
Ammonia is produced naturally by the action of certain types of bacteria on nitrogen found in the atmosphere. It is also formed during the decay of dead organisms.
Until the end of the nineteenth century, ammonia was produced commercially by the cyanamide process. Calcium carbide (CaC2), nitrogen gas (N2), and steam were reacted with each other to produce ammonia.
In the early 1900s, the German chemist Fritz Haber (1868–1934) developed a method for making ammonia directly from its elements, nitrogen and hydrogen. The two gases are combined with each other at high temperature (400°C to 650°C; 750°F to 1200°F) and pressure (200 to 400 atmospheres; 3,000 to 6,000 pounds per square inch) over a catalyst made of finely-divided iron. Haber's process was later refined and improved by German chemical engineer Carl Bosch (1874–1940). Haber and Bosch both won Nobel Prizes in chemistry for their work on the production of ammonia. The Haber-Bosch process remains the most common form of ammonia production in many countries, including the United States. Small amounts of ammonia are also produced during the process by which soft coal is converted to coke.
Ammonia is a natural product of metabolism in all animals. When proteins break down, the nitrogen they contain is converted, in part, to ammonia. The ammonia is then converted to urea, which is excreted in the urine.
Interesting Facts
- Ammonia's name comes from an ancient Egyptian practice conducted at the temple of the sun god Amon (or Ammon) near Karnak. Camel dung burned at the temple gave off a strong odor (ammonia) and left behind a white crystalline substance on the ground. The white substance was given the name of sal ammoniac, or salt of Amon, and the gas itself later became known as ammonia.
- The Haber-Bosch process was developed largely because of Germany's need for explosives in World War I. Ammonia gas is converted to nitric acid, which, in turn, is used in making sodium and potassium nitrate, major components of explosives. Fritz Haber believed that it was his patriotic duty to contribute to the German war effort in whatever way he could, which led to his development of a new method for making ammonia.
Common Uses and Potential Hazards
Ammonia is used in a variety of forms as a fertilizer. It can be liquified or dissolved in water and sprayed on land, or it can be converted into any one of a number of compounds, such as ammonium nitrate, ammonium phosphate, or ammonium sulfate. In these forms, it is spread as dry granules on the land. Urea, made from ammonia and carbon dioxide, is also used as a feed supplement for cattle. Plants and animals use the nitrogen in ammonia and its compounds to synthesize new proteins that contribute to their growth and development.
The next largest use of ammonia is in the synthesis of nitric acid (HNO3). In a process developed by the German chemist Wilhelm Ostwald (1853–1932), ammonia, oxygen, and water are reacted together in a series of steps that results in the formation of nitric acid. Nitric acid, the thirteenth most important chemical in the United States in terms of productions, has a number of important uses, including the manufacture of explosives. Like the Haber-Bosch process, the Ostwald process contributed to the success experienced by Germany during World War I.
In addition to its use in the manufacture of fertilizers and explosives, smaller amounts of ammonia are used:
- As a refrigerant;
- In the manufacture of plastics;
- As a raw material in the manufacture of other nitrogen-containing chemicals;
- In the production of dyes;
- As a rocket fuel;
- For the neutralization of acids during the refining of petroleum;
- In order to produce specialized types of steel; and
- As a nutrient in yeast cultures in food processing operations.
Both gaseous and liquid ammonia pose moderate health hazards to those who come into contact with them. For example, farmers who handle liquid ammonia risk the possibility of painful blistering of the skin or damage to the mucous membranes if they come into contact with the ferilizer. Ammonia fumes can irritate the mouth, nose, and throat, causing coughing and gagging responses. Higher levels of exposure may irritate the lungs, resulting in shortness of breath and producing headaches, nausea, and vomiting. Very high exposures can cause a buildup of fluid in the lungs that can result in death. Since ammonia is a common ingredient of many household products, everyone should be aware of its health risks, although the threat posed by such products is, in fact, very small.
Words to Know
A material that increases the rate of a chemical reaction without undergoing any change in its own chemical structure. The process including all of the chemical reactions that occur in cells by which fats, carbohydrates, and other compounds are broken down to produce energy and the compounds needed to build new cells and tissues. Tissues that line the moist inner lining of the digestive, respiratory, urinary and reproductive systems. A chemical reaction in which some desired chemical product is made from simple beginning chemicals, or reactants.For Further Information
"Ammonia." Masterliness. http://www.masterliness.com/a/Ammonia.htm (accessed on September 19, 2005).
Buechel, K. H., et al. Industrial Inorganic Chemistry. New York: VCH, 2000, pp. 29-43.
"The Facts about Ammonia." New York State Department of Health. http://www.health.state.ny.us/nysdoh/bt/chemical_terrorism/docs/ammonia_general.pdf (accessed on September 19, 2005).
"Toxicological Profile for Ammonia." Agency for Toxic Substances and Disease Registry. http://www.atsdr.cdc.gov/toxprofiles/tp126.html (accessed on September 19, 2005).
"Uses and Production of Ammonia (Haber Process)." Ausetute. http://www.ausetute.com.au/haberpro.html (accessed on September 19, 2005).
See Also
Ammonium Chloride; Ammonium Hydroxide; Ammonium Nitrate; Ammonium Sulfate; Nitric Acid; Potassium Nitrate; Urea
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