hodges
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Si + NaOH
Pretty energetic reaction:
http://www.youtube.com/watch?v=TinQ3iV403s
I'm certainly not agreeing with the guy's claims for this being a cheap source of hydrogen (uhm, how much energy is required to produce the Si
anyway....), but this is an energetic reaction that I had not read of before.
I'm guessing
Si + 2NaOH + H2O --> Na2SiO3 + 2H2
This might make a neat and relatively safe demo for energetic materials. I have Si powder - don't think it is too hard to get.
Hodges
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chemoleo
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Reminds me a bit of the reaction with Mg and NaOH - which practically is a flash powder when heated (dry solids) - I'd imagine, with water it'd behave
as here with the Si. The water of course only serves to get the reaction going - hence the self-ignition with a smaller amount of water.
That dude is a dork though - he annoys me! And as you say, it's everything but a cheap H2 source!
Professional lab? With dixie cups, and metal cans? ...right!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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DougTheMapper
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I'll venture to guess that a lot of the gas released was steam.
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Jor
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The splashing of all the droplets in the first reaction makes a mess... Wouldn't want to be in that caustic rain.
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vulture
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This idiot pisses me off. Silicon can be mined? Right. People like this make you consider approving the death penalty.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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hodges
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I tried this reaction. I used 0.6g of powdered Si, 2.0g of NaOH (used excess since it it likely not pure), and a moderate excess of water.
The reaction is fast, but only when the silicon is a fine powder. I tried putting little lumps of black silicon in a fairly concentrated NaOH
solution, and it reacts about as fast as iron does in HCl (i.e. not very fast). With finely powdered silicon the reaction is about as energetic as
adding a ball of Al foil to NaOH - besides the hydrogen, it definitely vaporizes some of the NaOH, resulting in irritating fumes if done indoors
without a fume hood.
Hodges
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ChrisWhewell
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Quote: Originally posted by hodges  | Pretty energetic reaction:
http://www.youtube.com/watch?v=TinQ3iV403s
I'm certainly not agreeing with the guy's claims for this being a cheap source of hydrogen (uhm, how much energy is required to produce the Si
anyway....), but this is an energetic reaction that I had not read of before.
I'm guessing
Si + 2NaOH + H2O --> Na2SiO3 + 2H2
This might make a neat and relatively safe demo for energetic materials. I have Si powder - don't think it is too hard to get.
Hodges
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What I would like most for Christmas, is to be able to go the other way, a reagent which when applied to a glass surface causes a layer of the SiO2
to be reduced to Si.
[Edited on 22-12-2009 by ChrisWhewell]
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12AX7
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Hydrogen/methane plasma???
Easier to deposit poly-Si with SiCl4 and heat (and maybe some plasma too).
Tim
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ChrisWhewell
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there's got to be a way to do it via magnetron.....
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not_important
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It's fairly tough to get from SiO2 to Si, the best route uses carbon. Really hard to do on glass because of the alkali and alkaline earth metals
content and the stability of their oxides and silicates.
Appears that in the SiO2-H2-H2O-Si system it is SiO2-H2 that are the stable states below around 1.500 K, SiO becoming increasingly important above
that until around 3.000 K while Si(g) arrives on the scene and becomes dominate in the upper 4.000s K.
See Fig 1 in the attached PDF
Attachment: phpEyrd2s (430kB)
This file has been downloaded 3652 times
Also see
http://adsabs.harvard.edu/abs/1993JJAPL..32L1273K
and DOI 10.1111/j.1551-2916.2005.00144.x
A plasma in acetylene might work, but the SiO2 substrate would have to be pretty toasty.
One more PDF : Low-temperature fabrication of silicon films by large-area microwave plasma enhanced chemical vapor deposition
Attachment: 01.09_jian-de_gu_pei-li_c_english.pdf (751kB)
This file has been downloaded 1541 times
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The WiZard is In
International Hazard
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| Quote: Originally posted by hodges | Pretty energetic reaction:
http://www.youtube.com/watch?v=TinQ3iV403s
I'm certainly not agreeing with the guy's claims for this being a cheap source of hydrogen (uhm, how much energy is required to produce the Si
anyway....), but this is an energetic reaction that I had not read of before.
I'm guessing
Si + 2NaOH + H2O --> Na2SiO3 + 2H2
This might make a neat and relatively safe demo for energetic materials. I have Si powder - don't think it is too hard to get.
Hodges
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The Silicol process "plants are made in sizes varying from
1500 to 80 000 cubic feet per hour production" used (me
thinks for economic reasons) ferro-silicon.
Details in :—
P. Litherland Teed
The Chemistry and Manufacture of Hydrogen
Longmans Green 1919
I ran down an original copy, you can DL yours from Google.com/books.
By da in long gone youth it was possible to buy lithium hydride
WW II surplus hydrogen weather balloon hydrogen generators.
Li hydride is some interesting stuff.
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michaeljayclark
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buy?
where can Si and NaOH be purchased?
interested in trying out this experiment
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Bot0nist
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Sodium hydroxide can be bought at most DIY stores even if you can't buy reagents online. Lye drain cleaner is what your looking for, though it often
contains potassium hydroxide as well. Powdered silicon can be bought all over the net. I use skylighter.com personally.
[Edited on 15-3-2011 by Bot0nist]
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kingkool
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| Quote: |
What I would like most for Christmas, is to be able to go the other way, a reagent which when applied to a glass surface causes a layer of the SiO2 to
be reduced to Si. |
Seal a microscope slide with magnesium. Heat it to ~600C for a couple of hours or with a bulk flame ( http://www.youtube.com/watch?v=MJ3oCT_HMoE ). You will have microscope slide with a blue layer. Heat this in air or under argon at 600-800C for a
few hours then dip in HCl.
See this patent: http://www.faqs.org/patents/app/20100092141
[Edited on 23-3-2011 by kingkool]
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