chochu3
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what is the definition of an activated metal?
I've looked in books and googled, but anyway, what is an activated metal? Suppose activated copper. If I add powdered aluminum to a solution of
coppper sulfate is the copper powder formed activated? Something else I read says when a metal is added to protons the metal becomes activated. Once
again, using copper as an example would adding hydrochloric acid activate it or would I have to use an strong oxidizing acid such as sulphuric acid to
activate it? My thoughts are that a metal must be activated only if electrons are moved around on the metal surface. Correct me and learn me where I
lack. Thank you in advanced for the replies.
\"Abiding in the midst of ignorance, thinking themselves wise and learned, fools go aimlessly hither and thither, like blind led by the blind.\" -
Katha Upanishad
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DJF90
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Aluminium wont react with copper sulphate solution due to its naturally protective oxide layer. Woelen's page has instructions for this experiment:
http://81.207.88.128/science/chem/exps/cu+al/index.html . I'm not sure if its activated or not though, and am also curious to what "activated" in this
context actually means.
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12AX7
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Active metals have incredibly high surface areas. They are usually colloidial powders or have fine microstructure which increases surface area.
Raney nickel for example is made from a brittle nickel-aluminum alloy which is finely ground; the aluminum is leached out with hydroxide, leaving
spongelike nickel particles with insane surface area. At least, that's what I understand the process is, it may vary.
Activated charcoal is similar: wood, which is reasonably solid crystalline cellulose (and etc.) with some natural porosity, after pyrolysis, becomes a
spongelike network of carbon atoms in myriad conformations. The immense surface area and variously sized nooks and crannies makes activated charcoal
an excellent absorbant for almost everything.
Tim
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Fleaker
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I think activation state is contextual and depends on what exactly one is doing.
In Raney's case, it usually has much hydrogen adsorbed onto the surface of the nickel, caused by the dissolution and complexaiton of the aluminum in
the base. This is true of palladium and platinum on carbon, when they are reduced from XCl2 to X (being any PGM) onto the activated carbon, they
usually gain some mass as hydrogen is picked up. This reduction is done at high temperature in a hydrogen atmosphere, and the product is cooled under
hydrogen gas.This can also make them potentially hazardous upon exposure to air, so care must be taken to transfer the product under H2 because the
catalyst is in an active state.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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Klute
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Actually, in the context of metals, I was considering "activated" meaning with any protective layer removed: amalgam with Hg for Al, acid wash for Zn,
etc..
Obviosuly "activated" can have lots of different meanings in different contexts, I would see it as the opposit of passivated here.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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