Savior
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Difussion Paranoia
Why is Gallium diffusing through Aluminium? Why is Mercury not diffusing through glass or any metal? Do gasses diffuse through anything? Does heavy
water diffuse thorough glass? How to prevent any diffusion and prevent accidental poisoning or explosion? What is theory behind this? Can it be
predicted?
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Chemosynthesis
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Consider posting in the Miscellaneous Short Questions/Answers thread next time as these all seem like pretty short ones.
Gallium can alloy or amalgamate with aluminum. This may have the consequence of gradually working through a piece of aluminum.
Mercury can amalgamate "through" metals, but glass is chemically inert to it. The cohesivity of mercury and the size of pores in the glass can keep it
from escaping.
Gasses diffuse through many things. Helium, for example, is very difficult to contain. Notice how balloons always seem to deflate?
"How to prevent any diffusion and prevent accidental poisoning or explosion?" Of what materials? Diffusion can be predicted depending on the material
states. You can start with variations of Fick's Law and move on: http://en.wikipedia.org/wiki/Diffusion_equation
You could also consider diffusion in light of "particle in a box" quantum models.
[Edited on 12-2-2015 by Chemosynthesis]
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blogfast25
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A particle in a box with limited potential energy walls? Diffusion as quantum tunnelling?
[Edited on 12-2-2015 by blogfast25]
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Chemosynthesis
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Yep. "Tunneling diffusion." Not something I would find particularly fulfilling, but apparently there are
publications on it. Mostly surface adsorption and one dimensional lattice modeling from the looks of it.
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blogfast25
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Nah. It won't catch on much... 
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aga
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Thread Moved.
Doh ! i'm not a moderator, or even moderately so.
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smaerd
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In most cases on the macro/newtonian scale quantum tunneling yields no real effect. Unless you're glass is 4-20nm thick.
For organic molecules... The particle in a box model basically says that an electron in a conjugated system can tunnel 1 C-C bond length (78pm?). That
is 1/2 of a bond length on either side. That's pretty negligable for most applications until we get down to nanoscopic scales. Under normal earth
conditions, a mercury atom for example tunnelling 78pm through a rigid energy barrier (glass)? Probably a very very very low statistical probability,
similar enough to a marble passing through the palm of your hand (IE: Doesn't happen in ordinary life, but maybe it could happen in the lifetime of
the universe). That's sterics aside.
Tunneling and diffusing are two different birds though. Amalgams even more different.
Chemosynthesis that's an interesting idea. For solution chemistry I'd have to see an example because in most cases that's considered "Co-diffusion".
The statistical mechanics POV makes good enough sense to me. IE the random walk approach derivation to the diffusion equation. I heard a lot of people
saying that the diffusion equation was outdated though, now if only I could remember the more preferential equations name...
Savior you could measure the diffusion constant of you're material in question. Something tells me though if you seal an ampoule of mercury you nor
your great great great great grandkids won't see anything interesting happen. Watch food dye diffuse through gelatin, it's a pretty slow process
without advection/convection/capillary action.
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IrC
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"Why is Mercury not diffusing through glass or any metal?"
They got a divorce. Their children's beaded little brains have been in therapy for eons.
'Any metal'? What, no Sodium?
"Science is the belief in the ignorance of the experts" Richard Feynman
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blogfast25
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Quote: Originally posted by smaerd  | In most cases on the macro/newtonian scale quantum tunneling yields no real effect. Unless you're glass is 4-20nm thick.
For organic molecules... The particle in a box model basically says that an electron in a conjugated system can tunnel 1 C-C bond length (78pm?). That
is 1/2 of a bond length on either side. |
Care to explain that a little? Not claiming you're wrong, just curious...
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