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Oxygen  O

 

Where is oxygen used--or where does it impact our everyday lives?

 

Oxygen is used to assist breathing in medicinal uses

 

Oxygen is used to enrich air in Nitrox in compressed breathing apparatus for SCUBA diving

--regular air is ~20% oxygen and one Nitrox mix could be 32% oxygen.

 

Oxygen

Symbol: O At # 8

Name means “acid forming”

Clear, colorless gas at room temperature

Melting Point: -218.4 °C

Boiling Point: -183.0 °C

Density (at room T): 1.429 g/L

Hazard: flammability with fuel and heat present

Abundance: 21% of air, 49% of the Earth’s crust.

Reacts with many elements --> oxides

Solubility in water: 40 mg/L (solubility, like all gas solubility, decreases with increasing temperature—less dissolves in warmer water)

Electron Configuration: Two in the first energy level and six in the second energy level: 2, 6 or !s2, 2s2 2p4

Main uses of the element: Well a big part of oxygen is keeping us alive (respiration), oxy-acetylene welding.

Discovered 1771 Carl Wilhelm Scheele, Sweden but not published.  Discovery of oxygen is credited to Joseph Priestley in 1774 in Calne, UK.

It is found in the environment as either O₂ in air or H₂O as water and as the allotrope ozone, O3, which is toxic to humans.

LANL.gov  Researcher B

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The cylinders were photographed where we purchase the liquid nitrogen for our Chemistry Two gas investigations.  Oxygen is used for medicinal and other purposes.

 

 

 

Oxygen is used to help acetylene (ethyne, C2H2) burn hotter in oxy-acetylene welding

 

        2C2H2  + 5O2 -->  4CO2  +  2H2O

 

 

 

 

 

 

 

 

 

 

 

 

Look to the left and also SEE THE VIDEO where oxygen is produced at the anode in the elctrolysis of dilute sulfuric acid

4OH-   -->  2H2O + O2 + 4e-

The anode, positive electrode, is made of platinum foil, and is connected to the positive, red terminal of the DC (direct current) power supply.

The hydrogen gas, H2, is collecting in the left-hand tube and there is twice as much hydrogen as oxygen gas, O2, which is collecting in the right-hand tube

 

 

 

 

 

A liquid oxygen tank used in 1931 by aeronautical pioneer Robert Goddard.  This artifact is displayed at the National Air and Space Museum, Steven F. Udvar-Hazy Center in Chantilly, Virginia, USA.  Photographed by WIS chemistry teacher and NASM Aerospace Educator

 

 

Oxygen

Many minerals contain metal oxides.  This sample is cassiterite, SnO2, tin IV oxide, from Cornwall, England, viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip

WIS Photographer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Oxygen from cylinders is available to supplement breating in a number of places--fire fighters, medicinal uses.  Aviators flying above 3,000 m (10,000 ft) need supplementary oxygen , if the airplane is unpressurized).  Pressurization of commercial airliners maintains internal airplane pressure equivalent to an altiude of no more than 2400 m (8,000 ft) and supplemental oxygen is available, if pressurization is compromized.   Video of United Airlines briefing emergency oxygen mask use on airplane

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and this is stibiconite (after stibnite) Sb3O6(OH) from Catorce, San Luis Potosi, Mexico viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip

WIS Photographer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Other oxygen containing minerals are metal carbonates.  This sample is aragonite, CaCO3, from Agrigento, Sicilia, Italy  viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip

WIS Photographer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Another carbonate mineral: malachite, CuCO3(OH)2, (after azurite) from Tsumeb, Namibia, viewed at the National Museum of Natural History, Washington DC during a Chemistry ONE field trip

WIS Photographer

Class of 2015 students in IB Chemistry investigating the dissolved oxygen content in Tregaron's pond and creek using the Winkler method which uses manganese sulfate to fix the dissolved oxygen in the water sample and then add acidified iodide to liberate iodine, which in turn is measured accurately with a sodium thiosulfate titration  I2 + 2Na2S2O3 --> 2NaI + Na2S4O6

SEE the video of students performing the Winkler method for dissolved oxygen.

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