2. OXYGEN O2

3. HISTORY NAME: Oxus (acid) and gennan (generate) Joseph Priestley
DISCOVERY:
1974
Carl Wilhelm Scheele
Oxygen is named from the Greek oxus (acid) + gennans (generate).
The name oxygen was created by Antoine Lavoisier who incorrectly believed that oxygen was necessary to form all acids.
For many centuries, workers occasionally realized air was composed of more than one component. The behavior of oxygen and nitrogen as components of air led to the advancement of the phlogiston theory of combustion, which captured the minds of chemists for a century. Oxygen was prepared by several workers, including Bayen and Borch, but they did not know how to collect it, did not study its properties, and did not recognize it as an elementary substance.
Priestley is generally credited with its discovery, although Scheele also discovered it independently.
advancement – rozvoj, vzestup, pokrok
combustion - hoření, vznícení, spalování

4. OCCURRENCE Most abundant element in the universe 21% of the atmosphere
49% of earth's crust
hydrosphere
biosphere
= significant biogenous element
Oxygen is the third most abundant element found in the sun, and it plays a part in the carbon-nitrogen cycle, the process once thought to give the sun and stars their energy. A gaseous element, oxygen forms 21% of the atmosphere by volume and is obtained by liquefaction and fractional distillation. The atmosphere of Mars contains about 0.15% oxygen. The element and its compounds make up 49.2%, by weight, of the earth's crust. About two thirds of the human body and nine tenths of water is oxygen.
In the laboratory it can be prepared by the electrolysis of water or by heating potassium chlorate with manganese dioxide as a catalyst.
It is significat biogenous element.
source – zdroj
abundant – hojný, oplývající, bohatý
earth's crust - zemská kůra

5. FORMS O2 Very reactive, colorless, odorless and tasteless gas
Exotermic reaction
Oxidation States: -2
Oxygen has nine isotopes. Natural oxygen is a mixture of three isotopes.
Oxygen is very reactiv, coroless, odorless and tasteless gas.
Reactions are strong exotermic. They accompany loosening light very often.
Oxidation states is -2.

6. FORMS O3 highly reactive, bluish, poisonous gas
Swallows up UV radiation
Ozon layer
Ozone (O3), a highly active compound, undiluted ozone has a bluish color. Liquid ozone is bluish black and solid ozone is violet-black., is formed by the action of an electrical discharge or ultraviolet light on oxygen.
Ozone's presence in the atmosphere helps prevent harmful ultraviolet rays of the sun from reaching the earth's surface. Pollutants in the atmosphere may have a detrimental effect on this ozone layer.

7. groun ozon electrical discharge – elektrický výboj harmful – škodlivý
In the picture is ozone layer on the south pole in 1981 and 1999.
Ground ozon occurs near the earth surface. Raising amount is watched in hot sommer days in places with hight automobile conveyance. This ozon is dangerous. It derogates air passages.
electrical discharge – elektrický výboj
harmful – škodlivý
detrimental – škodlivý, zhoubný
bluish – modravý

8. USES O2 O3 Respiration Welding and cutting of metal Rocket fuel
dezinfection
Plants and animals rely on oxygen for respiration. Hospitals frequently prescribe oxygen for patients with respiratory ailments.
Natural occurring oxygen-18 is stable and available commercially. Large quantities are also used in making synthesis gas for ammonia and methanol, ethylene oxide, and for oxy-acetylene welding and cutting metals.
Liquid Form is used as rocket fuel.
Air separation plants produce about 99% of the gas, while electrolysis plants produce about 1%.
Ozon has antibacterial effect. It is used for desinfection and ozonation fresh water.
rely – spoléhat
frequently – často
available – přístupný, dosažitelný
welding – svařování

9. References: http://periodic.lanl.gov/elements/8.html
xt/O/key.html
We used informations from internet (web pages).

10. Thank you for your attention !
Presentation was prepared by:
Andrea Urbanová
Lucie Vašíčková
Brno University of Technology