Fabrics that protect against chemical warfare agents

A new coating for textile fibers shows promise for efficiently capturing toxic industrial chemicals and chemical warfare agents under real-world conditions, including high humidity. The research could lead to improved masks ...

Scientists discover that charcoal traps ammonia pollution

Cornell University scientists Rachel Hestrin and Johannes Lehmann, along with collaborators from Canada and Australia, have shown that charcoal can mop up large quantities of nitrogen from the air pollutant ammonia, resulting ...

Making ammonia 'greener'

Ammonia, a compound first synthesized about a century ago, has dozens of modern uses and has become essential in making the fertilizer that now sustains most of our global food production.

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Ammonia is a compound of nitrogen and hydrogen with the formula NH3. It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or indirectly, is also a building-block for the synthesis of many pharmaceuticals. Although in wide use, ammonia is both caustic and hazardous. In 2006, worldwide production was estimated at 146.5 million tonnes. It is used in commercial cleaning products.

Ammonia, as used commercially, is often called anhydrous ammonia. This term emphasizes the absence of water in the material. Because NH3 boils at -33.34 °C (-28.012 °F) at a pressure of 1 atmosphere, the liquid must be stored under high pressure or at low temperature. Its heat of vapourization is sufficiently high so that NH3 can be readily handled in ordinary beakers, in a fume hood (i.e., if it is already a liquid it will not boil readily). "Household ammonia" or "ammonium hydroxide" is a solution of NH3 in water. The concentration of such solutions is measured in units of baume (density), with 26 degrees baume (about 30% w/w ammonia at 15.5 °C) being the typical high concentration commercial product. Household ammonia ranges in concentration from 5 to 10 weight percent ammonia.

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