| Liquid oxygen (O) is pale blue and extremely cold. Although
nonflammable by itself, oxygen is a strong oxidizer. Oxygen is the second
largest component of the atmosphere, comprising 20.8% by volume. Oxygen
is necessary to support life. Oxygen will react with nearly all organic
materials and metals usually forming an oxide. Liquid oxygen is a
cryogenic liquid. Liquid oxygen has a boiling point of -297.3°F
(-183.0°C or 90.21 K). Oxygen is often stored as a liquid, although it
is used primarily as a gas. Liquid storage is less bulky and less costly
than the equivalent capacity of high-pressure gaseous storage. A typical
storage system consists of a cryogenic storage tank, one or more vaporizers, a
pressure control system, and all piping necessary for the fill, vaporization,
and supply functions.
Several chemists had produced oxygen prior to its discovery in 1774, but
they failed to recognize it as a distinct element. Joseph Priestley and
Carl Wilhelm Scheele both independently discovered oxygen, but Priestly is
usually given credit for the discovery. They were both able to produce
oxygen by heating mercuric oxide (HgO). Priestley called
the gas produced in his experiments "dephlogisticated air"' and Scheele called
his "fire air." Antoine Lavoisier who incorrectly believed that oxygen
was necessary to form all acids created the name oxygen.
Oxygen accounts for nearly half of the mass of the earth's crust,
two-thirds of the mass of the human body, and nine tenths of the mass of
water. Large amounts of oxygen can be extracted from liquefied air
through a process known as fractional distillation. Oxygen can also be
produced through the electrolysis of water or by heating potassium chlorate
(KClO3).
Oxygen is a highly reactive element and is capable of combining with most
other elements. It is required by most living organisms and for most
forms of combustion. Impurities in molten pig iron are burned away with
streams of high-pressure oxygen to produce steel. Oxygen can also be
combined with acetylene
(C2H2) to produce an extremely hot flame used
for welding. Liquid oxygen, when combined with liquid hydrogen, makes an excellent rocket fuel.
Oxygen is also a component of hundreds of thousands of organic compounds.
|
 |
| Atomic Number |
8 |
| Atomic Weight |
15.9994 |
| Melting Point |
54.36 K |
| Heat of Vaporization |
212.9 kj/kg K |
| Specific Heat |
1.70 kj/kg K |
| Viscosity |
188.0 kg/m-s X 106 |
| Thermal Conductivity |
151.4 mW/m-k |
| Dielectric Constant |
1.4837 |
| Critical Temperature |
154.576 K |
| Critical Pressure |
5.04 MPa |
| Temperature at Triple Point |
54.35 K |
| Pressure at Triple Point |
.151 Mpa X 103 |
| Density |
.001429 grams/cc |
| Phase at Room Temperature |
Gas |
|
