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alpha particles
parts fpl alpha

Alpha particles. Helium atoms (4/2HO2+) without their electrons are produced in many nuclear reactions. Their air range is short (usually less than 10 cm) and they are easily stopped by a thin layer of paper or a metal foil.


aluminum
aluminum m

Aluminum. The most abundant metal in the Earth's crust (about 8 percent of the crust's mass). Its alloys are widely used in household appliances and industry.
Clay, shale, slate, and granite contain aluminum compounds, but extracting the metal from these materials is difficult. It is obtained by electrolysis of bauxite dissolved in cryolite using a graphite track.

The valency of aluminum is 3. Although it is a highly reactive metal, it and its alloys are resistant to corrosion as a result of the formation of a layer of oxide on its surface. Aluminum undergoes anodizing.


aluminum compounds
Composés mpl d'aluminium

Aluminum compounds.

Aluminum chloride AICI3
Anhydrous chloride co-anhydrous. covalent.

Aluminum oxide, Al2O3, is an amphoteric oscillator.

Aluminum sulphate Al2(SO4)3
The most important aluminum compound, it is used as a precipitant in sewage works, and as a softener and glue in the paper industry. It is also used as a foaming agent in fire extinguishers.

amalgam
amalgame m

Amalgam. An alloy containing mercury. . Zinc amalgam is used as a dental filling. Amalgamation was used in the past to extract gold and silver from ground rocks or dust containing minerals.

amino acids
Acids and amino acids

Amino acids. Organic compounds containing the groups COOH and NH, which are the building blocks from which proteins are made.
Making all the proteins in our bodies requires 20 different amino acids. The body can produce some of these amino acids itself, but there are eight acids that we need to eat with our food, which are the essential amino acids.
Amino acids combine with each other to form peptides.
Glycine.


ammonia (NH3)
ammoniaque f


Ammonia is a colorless gas with a sharp odor. It is highly soluble in water and gives an alkaline solution. Ammonia was previously made from coal, but today 90 percent of it comes from the Haber process.
Bacteria on the roots of leguminous plants, beans and peas, also produce ammonia. When protein breaks down, it releases ammonia, which both constitute an important source of plant nutrition.
See nitrogen cycle.

The following illustration shows the importance of ammonia in our daily lives:

Uses of ammonia

Ammonia >>>
Drugs
Cleaner in industry.
Fabric
Fertilizers [80 percent of production]
(ammonium sulfate)
(ammonium phosphate)
(ammonium nitrate)
Nylon industry
Bole (used to make plastics and resins)
Explosives.
(Ammonium nitrate) TNT.. TNT
Household cleaners
Nitrogen acid
Refrigerators
Sodium carbonate
(Solvay process)
nitric acid

Ammonia is a covalent compound, and it has a distinct reaction with hydrogen chloride, giving white vapors of ammonium chloride:

(solid) NHACI → (gas) HCI + (gas) NH3

Ammonia can be oxidized to give nitric acid, which is the main source of this acid today.
Ammonia is easy to liquefy and is usually transported in this state from one place to another by tankers.