Aluminum By Tara DeZao |
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| Aluminum is the third most abundant element in the earth’s crust. It takes up 8 %
of the earth’s crust. Scientists believe that aluminum was formed during the birth of
our solar system. It was born due to collisions of hydrogen atoms under high temperatures
and pressures. Aluminum has a high affinity to oxygen. It never occurs as a metal in
nature but in compounds such as alumina. In 1787 Antione Laviosier identified it as the
oxide of a then-undiscovered metal. In1807 Sir Humphry Davy assigned the metal the name
alumium, which was later changed to aluminum. Aluminum has the symbol Al. It is a silvery metal in-group IIIA of the periodic table. Its atomic number is 13 and its atomic weight is 26.9815. It is nonmagnetic and a good conductor of heat and electricity. Aluminum has a melting point of 660.24 degrees Celsius and a boiling point of 2450 degrees Celsius. The best-known property of aluminum is that it is Very light in weigh. It is one third as dense as iron, copper and zinc. Even though it is lightweight it can easily be made stronger to replace heavier, more costly metals. Aluminum and its many alloys are very resistant to corrosion. Its electrical alloy has the highest conductivity per pound of any commercially sold conductor. For this reason over 90% of the transmission and distribution lines in the US are made from aluminum. It is also a good conductor of heat. It is nine times as conductive as stainless steel. Due to its heat conductivity, aluminum is used in car radiators, cooling coils and fins. Aluminum is an excellent reflector of all forms of radiated energy. Because it reflects about 90% of radiated heat, aluminum is effective at keeping heat out or in. It is used in building insulation and roofing materials. Aluminum foil can be used to jam radar by reflecting it. It is used to conserve energy in both home heating and cooling. Aluminum storm doors and windows, insulation backed with aluminum foil, and aluminum siding are excellent insulators. Aluminum is also very workable, it is as weldable as steel at twice the rate. It is also substituted in cars for heavier metals to conserve fuel and get better gas mileage. Drive shafts, suspension parts and wheels are often made of aluminum. Aluminum has become very useful in the container and packing industry. The retort pouch used by the military is a flexible package mad of an aluminum laminate. Contaminants can’t enter the pouch and it can remain safe to eat for years. The United States is the biggest consumer and producer of aluminum. Us aluminum can recycling provides over half the aluminum used in making new cans, and recycling of aluminum scrap equals almost half of the total aluminum production. A mole is Avagadro’s number of any particle of definite composition. The term mole is also used to indicate the quantity of a substance that has a mass in grams numerically equal to its molecular mass. This mass contains Avagadro’s number of molecules. |
