oxygen-(O2)

               Oxygen-O2

Chemical properties of oxygen - 

Atomic number

8

Atomic mass

15.999 g.mol -1

Electronegativity according to Pauling

3.5

Density

1.429 kg/m3 at 20°C

Melting point

-219 °C

Boiling point

-183 °C

Vanderwaals radius

0.074 nm

Ionic radius

0.14 nm (-2)

Isotopes

4

Electronic shell

[ He ] 2s 2 2p 4

Energy of first ionisation

1314 kJ.mol -1

Energy of second ionisation

3388 kJ.mol -1

Energy of third ionisation

5300 kJ.mol -1

Discovered by

Joseph Priestly in 1774

Oxygen

Gaseous chemical element, symbol: O, atomic number: 8 and atomic weight 15,9994. It’s of great interest because it’s the essential element in the respiratory processes of most of the living cells and in combustion processes. It’s the most abundant element in The Earth’s crust. Nearly one fifth (in volume) of the air is oxygen. Non-combined gaseous oxygen normally exists in form of diatomic molecules, O2, but it also exists in triatomic form, O3, named ozone.

In normal conditions oxygen is a colourless, odourless and insipid gas; it condensates in a light blue liquid. Oxygen is part of a small group of gasses literally paramagnetic, and it’s the most paramagnetic of all. Liquid oxygen is also slightly paramagnetic.

Oxygen is reactive and will form oxides with all other elements except helium, neon, argon and krypton. It is moderately soluble in water (30 cm3 per 1 liter of water dissolve) at 20 Celsius.

Applications

Oxygen can be separated from air by fractionated liquefaction and distillation. The main applications of oxygen in order of importance are: 1) melting, refining and manufacture of steel and other metals; 2) manufacture of chemicals by controlled oxidation; 3) rocket propulsion; 4) medical and biological life support; 5) mining, production and manufacture of stone and glass products.

An emergency supply of oxygen automatically becomes available for the passenger in an aircraft when the pressure drop suddently. This oxygen is stored not as an oxygen gas but as the chemical sodium chlorate.

Entertainment of oxygen

The crust of earth is composed mainly of silicon-oxygen minerals, and many other elements are there as their oxides.

Oxygen gas makes up a fifth of the atmosphere, amounting to more than a million billion tonnes. The oxygen in the Earth's atmosphere comes from the photosyntesis of plants, and has built up in a long time as they utilised the abundant supply of carbon dioxide in the early atmosphere and released oxygen.

Oxygen is fairly soluble in water, which makes life in rivers, lakes and oceans possible. The water in rivers and lakes needs to have a regular supply of oxygen, for when this gets depleted the water will no longer support fish and other aquatic species.

Nearly every chemical, apart from the inert gasses, bind with oxygen to form compounds. Water, H2O, and silica, SiO2, main component of the sand, are among the more abundant binary oxygen compounds. Among the compounds which contain more than two elements, the most abundant are the silicates, that form most of the rocks and soils. Other compounds which are abundant in nature are calcium carbonate (limestone and marble), calcium sulphate (gypsum), aluminum oxide (bauxite) and various iron oxides, that are used as source of the metal

Oxygen uses:

 decreased O2 pressure at these altitudes.

Supplemental oxygen is needed for surgical patients intentionally rendered paralyzed for medical procedures, in which "heart-lung machines" keep their vital functions going.

Oxygen can be used as a sterilizing agent to kill certain anaerobic bacteria that are killed by sufficient exposure to the gas.

Industrial Uses of Oxygen:

Oxygen is needed for the reaction that converts carbon to carbon dioxide gas in steel working, which takes place under high temperatures in a blast furnace. The carbon dioxide produced allows for the reduction of iron oxides into more pure iron compounds.

Oxygen is used in other applications involving metal and requiring high temperatures, such as welding torches.

Aerospace Uses of Oxygen:

In liquid form, oxygen is used widely as an oxidizing agent for use in missiles and rockets, where it reacts with liquid hydrogen to produce the terrific thrust needed for take-off. Astronaut spacesuits include a nearly pure form of oxygen. 

Oxygen is used to degrade hydrocarbon compounds, which are broken apart by heating them. This is used to create combustion that usually liberates water and carbon dioxide, but can also produce the hydrocarbons acetylene, propylene and ethylene.

Oxygen is used in sewage-treatment and water-purification plants. It is forced through water to increase the production of bacteria that metabolize waste products in the water.

Oxygen gas (O2) is needed to produce energy in things not linked to an electrical supply of their own, such as generators and vehicles (e.g., ships, airplanes and cars).