Oxygen

nds:Suurstoff

Nitrogen - Oxygen - Fluorine
 
O
S  
 
 

General
Name, Symbol, NumberOxygen, O, 8
Chemical series nonmetals
Group, Period, Block16 (VIA), 2 , p
Density, Hardness 1.429 kg/m3 (273K), NA
Appearance colorless
Atomic Properties
Atomic weight 15.9994 amu
Atomic radius (calc.) 60 (48) pm
Covalent radius 73 pm
van der Waals radius 152 pm
Electron configuration [He]2s2s22p4
e- 's per energy level2, 6
Oxidation states (Oxide) -2,-1 (neutral)
Crystal structure cubic
Physical Properties
State of matter gas (paramagnetic)
Melting point 50.35 K (-368.77 °F)
Boiling point 90.18 K (-297.08 °F)
Molar volume 17.36 ×1010-3 m3/mol
Heat of vaporization 3.4099 kJ/mol
Heat of fusion 0.22259 kJ/mol
Vapor pressure __ Pa at __ K
Speed of sound 317.5 m/s at 293 K
Miscellaneous
Electronegativity 3.44 (Pauling scale)
Specific heat capacity 920 J/(kg*K)
Electrical conductivity __ 106/m ohm
Thermal conductivity 0.02674 W/(m*K)
1st ionization potential 1313.9 kJ/mol
2nd ionization potential 3388.3 kJ/mol
3rd ionization potential 5300.5 kJ/mol
4th ionization potential 7469.2 kJ/mol
Most Stable Isotopes
isoNAhalf-life DMDE MeVDP
16O99.762%O is stable with 8 neutrons
17O0.038%O is stable with 9 neutrons
18O0.2%O is stable with 10 neutrons
SI units & STP are used except where noted.
Oxygen is a chemical element in the periodic table that has the symbol O and atomic number 8. The element is common and ubiquitous, found not only on Earth but throughout the universe. Molecular oxygen (O2), as on Earth, is thermodynamically unstable, but exists through the action, first, of photosynthetic anaerobes and, in later epochs, of photosynthetic terrestrial plants.

Table of contents
1 Notable Characteristics
2 Applications
3 History
4 Occurrence
5 Compounds
6 Isotopes
7 Precautions
8 See also
9 External Links

Notable Characteristics

At standard temperature and pressure, oxygen is found as a gas consisting of two oxygen atoms, chemical formula O2. This oxygen is an important component of air, produced by plants during photosynthesis and is necessary for animals' respiration. The word oxygen derives from two words in Greek, the Greek oxus (acid) and gennan (generate).

Liquid oxygen and solid oxygen have a light blue color and both are highly paramagnetic. Liquid oxygen is usually obtained by the fractional distillation of liquid air.

Applications

Oxygen finds considerable use as an oxidizer, with only fluorine having a higher electronegativity. Liquid oxygen finds use as an oxidizer in rocket propulsion. Oxygen is essential to respiration, so oxygen supplementation has found use in medicine. People who climb mountains or fly in airplanes sometimes have supplemental oxygen supplies (as air). Oxygen is used in welding, and in the making of steel and methanol.

Oxygen, as a mild euphoric, has a history of recreational use that extends into modern times. Oxygen bars can be seen at parties to this day. In the 19th century, oxygen was often mixed with nitrous oxide to promote a kind of analgesic effect.

History

Oxygen was discovered by the Swedish pharmacist Karl Wilhelm Scheele in 1771, but this discovery was not immediately recognized, and the independent discovery by Joseph Priestley was more widely known. It was named by Antoine Laurent Lavoisier in 1774.

Occurrence

Oxygen is the most abundant element in the Earth's crust, estimated to comprise 46.7% of the crust. Oxygen comprises about 87% of the oceans (as H2O, water) and 20% of the atmosphere of Earth (as O2, molecular oxygen, or O3, ozone). Oxygen compounds, particularly metal oxides, silicates (SiO44-) and carbonates (CO32-), are commonly found in rocks and soil. Frozen water is a common solid on the outer planets and comets. The ice caps of Mars are made of frozen carbon dioxide. Oxygen compounds are found throughout the universe and the spectrum of oxygen is often seen in stars. In fact stars wouldn't produce light without oxygen.

Compounds

Due to its electronegativity, oxygen forms chemical bonds with almost all other elements (which is the origin of the original definition of oxidation). The only elements to escape the possibility of oxidation are a few of the noble gases. The most famous of these oxides is of course hydrogen oxide, or water (H2O). Other well known examples include compounds of carbon and oxygen, such as carbon dioxide (CO2), alcohols (R-OH), aldehydes, (R-CHO), and carboxylic acids (R-COOH). Oxygenated radicalss such as chlorates (ClO3-), perchlorates (ClO4-), chromates (CrO42-), dichromates (Cr2O72-), permanganates (MnO4-), and nitrates (NO3-)are strong oxidizing agents in and of themselves. Many metals such as Iron bond with oxygen atoms, Ferric Oxide (Fe2O3). Ozone (O3) is formed by electrostatic discharge in the presence of molecular oxygen. A double oxygen molecule (O2)2 is known, found as a minor component of liquid oxygen. Epoxides are ethers in which the oxygen atom is part of a ring of three atoms.

Isotopes

Oxygen has three stable isotopes and ten known radioactive isotopes. The radioisotopes all have half lives of less than three minutes.

Precautions

Prolonged exposure to pure oxygen at higher pressures can be toxic, having both pulmonary and neurological effects. Pulmonary effects include edema, loss of lung capacity and damage to lung tissues. Neurological effects can include loss of vision, convulsions and coma.

Certain derivatives of oxygen, such as ozone (O3), hydrogen peroxide, hydroxyl radicals and superoxide, are also highly toxic. The body has developed mechanisms to protect against these toxic species. For instance, the naturally-occurring glutathione can act as an antioxidant, as can bilirubin which is normally a breakdown product of hemoglobin. Highly concentrated sources of oxygen promote rapid combustion and therefore are fire and explosion hazards in the presence of fuels. This is true as well of compounds of oxygen such as chlorates, perchlorates, dichromates, etc. Compounds with a high oxidative potential can often cause chemical burns.

The fire that killed the Apollo 1 crew on a test lauchpad spread so rapidly because the pure oxygen atmosphere was at normal atmospheric pressure instead of the one third pressure that would be used during an actual launch. (see partial pressure)

See also

External Links


Oxygen is also the name of a Cable TV channel in the US. Its programming targets women audience.



In the News

Congenital Heart Disease Increasingly More Common In Adults, Children
The prevalence of congenital heart disease has increased strikingly in adults and children in a new population study, researchers reported in Circulation: Journal of the American Heart Association.

Cholesterol Treatment May Slow Alzheimer's Disease Progression
Cholesterol lowering drugs, including statins, may slow the progression of Alzheimer's disease, concludes a study in the Journal of Neurology Neurosurgery and Psychiatry. The research team assessed the degree of brain function loss caused by Alzheimer's disease in 342 patients attending a memory clinic. They then monitored the progress of the disease for almost three years.

Combination Hormone/Vaccine Therapy For Prostate Cancer May Benefit Pa
A new study finds that a cancer vaccine combined with hormone-deprivation therapy can help patients with recurrence of prostate cancer. The results of this clinical trial, led by scientists at the National Cancer Institute (NCI), part of the National Institutes of Health, appear in the August 2005 issue of the Journal of Urology.

Tsunamis and Earthquakes
Provides "general information on how local tsunamis are generated by earthquakes as well as animations, virtual reality models of tsunamis, and summaries of past research studies."From the United States Geological Survey (USGS).

[Absurd] Lawyer's £300,000 for writing letter
A German lawyer won himself a place in the Guinness Book of Records after he earned more than £300,000 for less than an hour's work...

Mapping the Pacific Coast: Coronado to Lewis and Clark, the Quivira Co
Companion to an exhibition of "maps, books and illustrations, dated 1544 through 1802, of the west coast of North America."View annotated map images (some with audio clips) on topics such as early explorers, California as an island, secret Russian exploration in the Pacific, Captain James Cook's voyages to the north Pacific, and overland to the Pacific in the late 1700s. From the Sonoma County (California) Museum and a California winery.

Glaucoma Finding: Experiments Show How Increased Pressure In Eye Leads
New research from Children's Hospital Boston and the Massachusetts Eye and Ear Infirmary may help explain how glaucoma causes blindness, revealing the chain of events that ultimately damage the optic nerve, preventing visual information from getting to the brain. The study indicates possible targets for intervention, including one for which there are already approved drugs.

New species of lichen discovered in Iberian Peninsula
Spanish scientists have described the lichen Phylloblastia fortuita, new to the Iberian Peninsula and to science. Another species from the same family, Phylloblastia dispersa, is also a new entry for Europe and is the first time it has been found outside the tropics.

Targeted therapy prolongs life in patients with HER2-positive breast c
Lapatinib plus trastuzumab are significantly better than lapatinib alone in extending the lives of breast cancer patients whose tumors are HER2-positive, according to new research.

OHSU Discovery Sheds Light Into How Stem Cells Become Brain Cells
Researchers discovered one key gene that appears to control how stem cells become various kinds of brain cells. The scientists wanted to determine if the process can be controlled and used as a possible therapy. What amazed them is a single gene may be responsible for this important task The finding has significant implications for the study of Parkinson's disease, brain and spinal cord injury, and other conditions or diseases.




MP3 Music Downloads

Preview songs, Download Free Music,Burn CDs at ITunes.com
iTunes_RGB_9mm

 


Google




InformationQuickFind.com - Find Information Fast

Links | Privacy Policy | News |