Oxygen


Oxygen, symbol O, colorless, odorless, tasteless, slightly magnetic
gaseous element. On earth, oxygen is more abundant than any other element.
Oxygen was discovered in 1774 by the British chemist Joseph Priestley and,
independently, by the Swedish chemist Carl Wilhelm Scheele; it was shown to be
an elemental gas by the French chemist Antoine Laurent Lavoisier in his classic
experiments on combustion.
Large amounts of oxygen are used in high-temperature welding torches, in
which a mixture of oxygen and another gas produces a flame of much higher
temperature than is obtained by burning gases in air. Oxygen is administered to
patients whose breathing is impaired and also to people in aircraft flying at
high altitudes, where the poor oxygen concentration cannot support normal
respiration. Oxygen-enriched air is used in open-hearth furnaces for steel
manufacture.
Most of the oxygen produced in the United States is used to make a
mixture of carbon monoxide and hydrogen called synthesis gas, used for the
synthesis of methanol and ammonia. High-purity oxygen is used also in the metal-
fabrication industries; in liquid form it is of great importance as a propellant
for guided missiles and rockets2.
I have chosen the element "Oxygen" because without Oxygen, human beings
would not be able to live. Oxygen is probably the single most important element
in the world as we know it. With out Oxygen we would not breath, have water, eat
plants.
Oxygen\'s Electron configuration is 1S2 + 2S2 + 2P4, it\'s electron dot
symbol is: .
Gaseous oxygen can be condensed to a pale blue liquid that is
strongly magnetic. Pale blue solid oxygen is produced by compressing the
liquid. The atomic weight of oxygen is 15.9994.Oxygen composes 21
percent by volume or 23.15 percent by weight of the atmosphere; 85.8
percent by weight of the oceans and, as a constituent of most rocks and minerals,
46.7 percent by weight of the solid crust of the earth. Oxygen comprises 60
percent of the human body. It is a constituent of all living tissues; almost all
plants and animals, including all humans, require oxygen, in the free or
combined state, to maintain life.3
Three structural forms of oxygen are known: ordinary oxygen, containing
two atoms per molecule, formula O2; ozone, containing three atoms per molecule,
formula O3; and a pale blue, nonmagnetic form, O4, containing four atoms per
molecule, which readily breaks down into ordinary oxygen. Three stable isotopes
of oxygen are known; oxygen-16 (atomic mass 16) is the most abundant. It
comprises 99.76 percent of ordinary oxygen and was used in determination of
atomic weights until the 1960s.
Oxygen is prepared in the laboratory from salts such as potassium
chlorate, barium peroxide, and sodium peroxide. The most important industrial
methods for the preparation of oxygen are the electrolysis of water and the
fractional distillation of liquid air. In the latter method, air is liquefied
and allowed to evaporate. The nitrogen in the liquid air is more volatile and
boils off first, leaving the oxygen. Oxygen is stored and shipped in either
liquid or gaseous form.
Oxygen is a component of many organic and inorganic compounds. It forms
compounds called oxides with almost all the elements, including some of the
noble gases. A chemical reaction in which an oxide forms is called oxidation.
The rate of the reaction varies with different elements. Ordinary combustion, or
burning, is a very rapid form of oxidation. In spontaneous combustion, the heat
evolved by the oxidation reaction is sufficiently great to raise the temperature
of the substance to the point that flames result. For example, phosphorus
combines so vigorously with oxygen that the heat liberated in the reaction
causes the phosphorus to melt and burn. Certain very finely divided powders
present so much surface area to the air that they burst into flame by
spontaneous combustion; they are called pyrophoric substances. Sulfur, hydrogen,
sodium, and magnesium combine with oxygen less energetically and burn only after
ignition. Some elements, such as copper and mercury, form oxides slowly, even
when heated. Inactive metals, such as platinum, iridium, and gold, form
oxides only through indirect methods. For discussion of oxides of elements see
separate articles on each element.3
A Guy jumps of a ship in the middle of the ocean and he swims and swims
towards an island. Having second thoughts about leaving the world, he started
screaming at a passing ship. The added oxygen to his blood caused his face to
turn dark purple. The captain of the ship saw the man, waived to him, and didn\'t
pick him up. I guess it was because he was "Marooned."

Category: Science