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Author Topic: Liquid Oxygen  (Read 5908 times)

Offline chris

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Liquid Oxygen
« on: 11/05/2005 21:27:46 »
Why is liquid oxygen a beautiful pale blue colour, and why is it magnetic ?

Chris

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Offline neilep

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Re: Liquid Oxygen
« Reply #1 on: 11/05/2005 22:51:19 »
Chris....I hope this helps http://chemed.chem.purdue.edu/demos/moviesheets/8.6.html

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Offline daveshorts

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Re: Liquid Oxygen
« Reply #2 on: 11/05/2005 23:16:12 »
For a substance to be paramagnetic (if you apply a magnetic field, the substance will become weakly magnetic in the same direction as the magnetic field) the atoms have to act as little magnets, they can do this because the electrons in some senses are orbiting and therefore acting as electromagnets.

- This much weaker than ferromagnetism, where all the atom magnets align of their own accord.

Electrons in atoms tend to pair up, with one electron going one way around the nucleus and another going the other. In this case the magnetic fields cancel out so the substance is not paramagnetic. This is the case with a nitrogen molecule, so liquid nitrogen isn't paramagnetic. Molecular oxygen however does have two unpaired electrons so they can produce a net magnetic field.

http://www.chem.uiuc.edu/clcwebsite/liquido2.html

The colour would appear to be related, in that if two oxgen molecules collide and are hit by red light, the unpaired electrons in both molecule will pair up in one orbital, absorbing the photon. As red light is absorbed the liquid oxgen looks blue. As this only happens in collisions it is very unlikely in the gas state, so only liquid or very high pressure oxygen looks blue.

http://chemed.chem.purdue.edu/demos/main_pages/8.6.html
 

Offline DoctorBeaver

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Re: Liquid Oxygen
« Reply #3 on: 17/05/2005 00:32:06 »
*thinks Chris should get back to his radio program & get on with answering questions rather than asking them! (Only joking, Chris! heh)

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Re: Liquid Oxygen
« Reply #3 on: 17/05/2005 00:32:06 »

 

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