redbaron
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What the hell did my class create?
Two very stupid kids in my AP Chemistry class wanted to see HF dissolve glass, but it was only a 5% solution and did not have any instant effects.
They attempted to heat the solution to speed up the reaction... so they heated the beaker with a bunsen burner, and whether the glass melted from the
intense heat or dissolved from the solution, the bottom gave and caused a huge mess (thankfully my teacher was busy with the regents class lab...)
When we cleaned it up (in the fume hood, at least) we noticed a thin layer of a rubbery, stretchy substance where the glass had dissolved. We didn't
have time to test the substance, as the period was ending and we had a mess of melted glass and a toxic acid solution that needed to be cleaned, but I
was trying to figure out what we may have created. I was thinking, could it have possibly been polydimethylsiloxane (silly putty)? If the natural gas
from the bunsen burner had reacted, then I think this is feasible. (C2H6OSi)n is the formula, so if this is the case, the low density hydrocarbons
could have reacted with the dissolving glass and oxygen in the air, but it definitely seems like a stretch. Any ideas what this mystery substance
could be?
[Edited on 17-2-2007 by redbaron]
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12AX7
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There would be a few methyl (and methylene, and CH) radicals around, but not enough to react with the whole thing. More likely, you got some sort of
silica gel compound -- waterglass dries to a rubbery solid before becoming glassy. I don't know about the fluoride though.
Tim
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redbaron
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| Quote: | Originally posted by 12AX7
There would be a few methyl (and methylene, and CH) radicals around, but not enough to react with the whole thing. More likely, you got some sort of
silica gel compound -- waterglass dries to a rubbery solid before becoming glassy. I don't know about the fluoride though.
Tim |
Thanks, that makes sense. I'll see on monday if the density is similar to any common silicates.
I forgot to mention, when the glass melted it smothered the burner, so I'm sure the fume hood was full of natural gas while the reaction took place.
You are probably right though, I doubt it was part of the reaction.
[Edited on 18-2-2007 by redbaron]
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tnhrbtnhb
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| Quote: | Originally posted by redbaron
| Quote: | Originally posted by 12AX7
There would be a few methyl (and methylene, and CH) radicals around, but not enough to react with the whole thing. More likely, you got some sort of
silica gel compound -- waterglass dries to a rubbery solid before becoming glassy. I don't know about the fluoride though.
Tim |
Thanks, that makes sense. I'll see on monday if the density is similar to any common silicates.
I forgot to mention, when the glass melted it smothered the burner, so I'm sure the fume hood was full of natural gas while the reaction took place.
You are probably right though, I doubt it was part of the reaction.
[Edited on 18-2-2007 by redbaron] |
I don't know about the silicates, but the glass is not melting; a section of the container expands from the heat, and the rest can't take the stress,
so it shatters. Borosilicate glass (pyrex) is a bit more resistant to this. That's why they say "do not use over open flame".
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