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chemoleo
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Experiments with liquid Nitrogen...
I am in a somewhat lucky position, having access to liquid N2 anytime.
Can anyone think of interesting experiments to do with it? For instance, I remember the Na solvation experiment which happily dissolves in liquid
ammonia. Are there similar experiments like this, i.e. unexpected solutions of compounds in N2(l)?
Of course there are many reactions that can be done with extremely unstable compounds, unfortunately they are often hazardous (such as oxides of
halogens, halogen-halogen compounds, compounds in a very high oxidation state that'd normally decompose, and so on).
Or are there compounds that can be only made at very low temps, and yet persist at RT (unlikely from a thermodynamic perspective)?
Any ideas? I haven't gotten further than freezing ethanol and various liquids.
It's quite interesting to see that ethanol becomes as viscous as glycerol when it reaches its freezing point. On the fingers, it nearly feels
sticky (like glycerol) which doesn't last long of course because it heats up.
Another experiment was to accidentially freeze the fingertip of my thumb - I noticed nothing until a sharp pain hit me. By that time, the tip of my
thumb was solid and whitish. Once defrosted, it hurt a little, stung, and after a few days the skin started to peel off. I was lucky it didnt go very
deep.
For that matter, I know that warts and such are removed with liquid nitrogen, it seems to work as seen with my little thumb experiment!
Oh, and freezing glacial acetic acid, or diethanolamine with it worked very well - two liquids that'd normally refuse to crystallise at 4 deg C
or so.
Any input/suggestions welcome (except those that involve bodily parts  )
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Twospoons
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How about Making high TC superconductor
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The_Davster
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Not chemistry related but I read something a while back about speeding up your computer by making a liquid nitrogen cooling system. If I remember
correctly it was called overclocking.
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neutrino
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Overclocking isn’t necessarily cooling the processor. Rather, it’s modifying the processor’s instructions in some way to run faster. This
generates heat which tends to fry the chip, which is why you need a good cooling system. I have heard of making chips run faster by cooling (or
something like that), but I think only works with a few of them.
Back to playing with the nitrogen: a couple of fun things to do with it are: 1.make ice cream (you get a nice, smooth ice cream because a.the nitrogen
vaporizes very quickly, preventing big crystals from growing and b.the nitrogen arêtes (not sure what the right word here is) the cream), 2.make dry
ice, 3.spill it onto a metal table and watch the drops flying around on a cushion of nitrogen gas 4.put it on your tongue (the same principle), and
lots of other stuff.
You may want to look here.
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The_Davster
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Ah thanks for clarifing that for me neutrino.
I have made liquid nitrogen icecream before and it is superior to most icecreams I have tasted.
Make liquid oxygen...I am sure you can figure out many uses for this yourself.
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JohnWW
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Liquid nitrogen is used in minor surgery, to remove warts, moles, and small benign tumors, by freezing them hard and cracking them off.
As for high-temperature superconductors, only the recently-discovered yttrium-barium-copper mixed oxides and similar ceramic compositions which have
lattice vacancies and a metal in more than one oxidation state (2 and 3 in the case of copper) are superconducting at as high as liquid nitrogen
(boils at 77ºK) temperatures.
[Edited on 4-3-2005 by JohnWW]
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I am a fish
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You could cool polymers to below their transition-to-glass temperatures. At 77K, rubber tubing will shatter rather than bend.
You could make chlorine ice. (Chlorine freezes at 172K.)
You could make liquid oxygen. (Oxygen liquifies at 90K). The reaction between liquid oxygen and many combustible substances is very
impressive.
If you have access to a vacuum dessicator, you could make nitrogen ice, by subjecting liquid nitrogen to vacuum. (Nitrogen boils off, cooling
the remaining liquid.)
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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mick
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Liquid nitrogen is used in minor surgery, to remove warts, moles, and small benign tumors, by freezing them hard and cracking them off.
From personal experience I think that is dri-ice. Genital warts appear and need to be sorted out, after all the pills and other stuff freezing with
dri-ice worked. They need sorting out because they have been linked cervical cancer, herpes etc. If they were going to sort it out with liquid
nitrogen I do not think I would have turned up.
mick
With liquid nitrogen you can make slush baths and know it is that temperature. I think if you fill a metal container with it, liquid oxygen might
condense underneath it.
mick
edite to add
[Edited on 4-3-2005 by mick]
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alchemie
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| Quote: | Originally posted by I am a fish
You could cool polymers to below their transition-to-glass temperatures. At 77K, rubber tubing will shatter rather than bend.
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This is fun. The rubber tubing shatters just like glass when you hit it.
If you do this with a latex glove it looks like you are breaking french fries (the thin ones). Just freeze one, throw it to the ground and stomp on it
and you'll see what I mean.
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runlabrun
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You could make what has been said to be the worlds best iced cream!!!
http://www.polsci.wvu.edu/Henry/Icecream/Icecream.html
and many more
http://www.google.com.au/search?hl=en&q=liquid+nitrogen+...
Apparently the liquid N2 makes it ice crystal free so your result is perfectly smooth ice cream and also i read its very fluffy due to the aeration
action of the N2 bubbling off....
Mmmmm sounds nice...
-rlr
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Skinflint
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I have a 25 liter LN2 tank that I fill up sometimes. It really does make great ice cream. I can tell you a lot of fun activities to do with liquid
nitrogen, but it is hard to think of scientific applications. An interesting thing to do is to break open an incandecent light and put the filament
into the LN2 and light it up. The filament just being near the surface of liquid nitrogen will protect it from oxidation.
It is also a lot of fun to spit liquid nitrogen. If measure out a teaspoon or so and put it in you mouth then quickley spit it out, it make a huge
amount of smoke. Very impressive and not as dangerous as it sounds. A teaspoon swallowed will just make you burp a lot.
You could use it to liquify methane and use that as a solvent, or study the magnetic properties of cryogenically cooled copper. It would be
interesting to freeze a bit of mercury in a mold of a nail and pound it into a board. Hg is supposed to be as hard as steel at those temperatures.
Thats all the ideas I can come up with.
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JohnWW
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with regard to Chemoleo's orignal post, it is quite likely that alkali metals would react with liquid N2 to form, in succession, the anions
•N=N-, -N=N-, -•N-N--, and N---, similarly to the gas-phase reaction.
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chloric1
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Aluminum and magnesium
I hear these metals are extreamely fragile at liquid nitrogen temperatures. You could pound these with a heavy hammer and when you have
shards/granules then you can ball mill these for a week or so with stearin.
Also, you could condense or freeze equilmolar amounts of NO and NO2 to form unstable N2O3 and directly neutralize with NaOH, or KOH or any other
strong alkali to get the pure nitrite.
Fellow molecular manipulator
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neutrino
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In the link I posted, a couple of people were talking about freezing tanks of butane, cutting them open, and playing with the butane ice inside.
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unionised
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Here's a tale about what NOT to do with it.
http://pharyngula.org/index/weblog/comments/aaiieee_dont_eve...
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sparkgap
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Jeez, urban legend or not, it's wacko to take a swig of something that liquefies below 0 °C !!!!!
That was dumb.
Oh, and chloric, ballmill with stearin? Why would a glyceride be needed for ballmilling a metal?
sparky (~_~)
P.S. I wonder how molten agar (or gelatin) would behave when poured in liquid N<sub>2</sub>? 
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neutrino
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I read that one before, but don’t remember the scars or hospital visit. What it said happened was that he mixed up holding liquid nitrogen on his
tongue and drinking it. Not too smart, but possible.
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garage chemist
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Neutrino, that link was good. I haven't read it entirely, but got to the solid butane experiments and pictures.
I wonder if propane can also be used? Because propane is much cheaper than butane and available in 5kg- tanks.
It'll surely liquefy, but I'm not sure if it will freeze.
I also have access to liquid nitrogen at any time, but its expensive (2,50€/liter) and I have to buy several liters.
I always wanted to make liquid ammonia, dissolve sodium in it and add an iron catalyst to make NaNH2 (which directly gives NaCN on heating with
charcoal).
But LN2 is way too cold for this (the ammonia would solidify) and dry ice isn't available.
Liquid oxygen is great fun to play with , I once did the cigarette-in-LOX experiment in school and it burned rapidly with a fascinatingly bright
purple flame. At the end, the LOX soaked cotton filter deflagrated as if it was guncotton.
A piece of charcoal soaked in LOX exploded on lighting, scattering white hot charcoal pieces over the entire room and causing our teacher to dispose
of the remaining LOX to stop further experimenting.
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sparkgap
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Methinks propane would solidify. ChemFinder says propane melts @ -187.778 °C, while liquid N<sub>2</sub> boils @ ~ -195 °C.
sparky (^_^)
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garage chemist
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Good, I'll try the propane thing when I get some LN2.
I also read that many colored substances change colour when cooled with LN2. Sulfur, for example, becomes white as chalk. Bromine first solidifies and
then the color changes to a light yellow-orange.
Lead, at room temp, is soft, but at LN2 temp it is hard and elastic as steel. A bell made of lead rings like it was silver when cooled and hit with a
metal rod.
Maybe you can hammer a nail made of soldering lead/tin wire into a piece of wood?
I once had some molten chocolate on a carpet and it was sticky and impossible to remove. After pouring LN2 on it, it could easily be scraped off.
[Edited on 6-3-2005 by garage chemist]
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The_Davster
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Just thought of another idea, make liquid ammonia and then dissolve alkali metals. If you were so inclined you could then use the solution of alkali
metal in ammonia to make the azide of the metal dissolved.
EDIT: This will not work as pointed out by sparkgap. I do not know why I was thinking ammonia would still be liquid at these temperatures.
[Edited on 6-3-2005 by rogue chemist]
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sparkgap
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garage chemist already mentioned that ammonia will freeze at the temperature of liquid N<sub>2</sub>.
You may want to take a look at ChemFinder or any chemical handbook if you believe the contrary.
sparky (^_^)
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Saerynide
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| Quote: |
I once had some molten chocolate on a carpet and it was sticky and impossible to remove. After pouring LN2 on it, it could easily be scraped off.
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Your carpet fibres didnt shatter and break off?
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garage chemist
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No, the fibers didn't shatter, they remained flexible. Don't ask me why, though.
I have a pair of plastic tweezers for handling a superconducting pellet. They also remain flexible at LN2 temperatures. It must be a special kind of
plastic...
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chloric1
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| Quote: |
Oh, and chloric, ballmill with stearin? Why would a glyceride be needed for ballmilling a metal?
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Basically sparky, when these metals get in a finely divided state they may become pyrophoric. THe stearin is merely a precaution that can eeasily
removed with toluene and next with ether. The grinding media would be steel balls or lead if you where paranoid about sparks. Lead may contaminate
though.
Fellow molecular manipulator
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