Chemistry Reference
In-Depth Information
OXYGEN (O
)
2
Properties
Oxygen is a colorless, odorless, and tasteless gas, that
makes up about 21% of the Earth's atmosphere. It
is essential to life for almost all living matter. It is
found in nature in combination with all elements
except the so-called rare gases (helium, argon, and
neon). It can be liquefied under pressure.
Commercial grades
Shipped at a minimum 99.5% purity as a liquid in steel
cylinders. Available as pure as 99.995%.
Uses
Metallurgy (e.g., making steel), metal fabrication,
chemical manufacture, medical and life-support
applications, sewage treatment, rocket propellant,
paper bleaching.
Manufacture
By distillation of liquid air, the same as nitrogen. Most
oxygen is used captively, less than 20% of
production being sold on the merchant market.
Suppliers
Air Liquide America Corp., Air Products and
Chemicals, BOC Gases, Praxair.
Chemical reactions in which oxygen atoms become attached to other
elements are termed
. Such reactions almost always result in the
release of energy in the form of heat. Some oxidations are rapid, like the
burning of wood or natural gas, with the evolution of heat and light. In this
case, the oxygen combines with the carbon in the materials being oxidized
(burned) to form carbon dioxide.
oxidations
CH
4
+
2O
2
CO
2
+
2H
2
O
+
Heat
Other oxidations, like the rusting of iron at room temperature, proceed
slowly with a slow release of heat. In the case of iron, the final product is
iron oxide (rust).
