To all, A colloid is both a dispersion and a suspension. It is not a solution. Most suspensions involve quite large particles, so I may not be correct there.
"When one substance dissolves in another to form a true solution, the ultimate particles of the solute are of molecular dimensions: at most a few molecules bay be joined together to form an associated species, such as occurs when benzoic acid dimerizes to form the molecule (C6H5COOH)2 in benzene. The radius of the solute molecule in these cases is seldom more than a nanometer and usually rather less. Solute and solvent molecules are of comparable size and we normally assume that the solute molecules are, on average, dispersed uniformly through the (continuous )solvent. There is an important class of materials, however, in which the kinetic units that are dispersed through the solvent and are very much larger in size than the molecules of the solvent. Such systems are called colloidal dispersions and they may arise in a variety of ways." Foundations of Colloidal Science, Vol I, page 1, section 1.1. Robert J. Hunter. U of Sidney, Australia James Osbourne Holmes [email protected] FTNWO -----Original Message----- From: Fred [SMTP:[email protected]] Sent: Friday, June 16, 2000 1:11 PM To: [email protected] Subject: CS>Re:H2O2 test At 12:52 PM 6/16/2000, you wrote: >A single "dissolved" atom of Ag is still a metal. It does not stop being, >by definition, a "metal" when it is a single atom in water. > >A clump of silver, regardless of size, or charge, is still not >"dissolved". It is by definition, a colloid. > >James Osbourne Holmes >[email protected] Not sure who you were addressing James, but I agree an atom = metal = element! The definition of a colloid seems to have many experts and thus answers, but I think you went amiss with a piece of silver = colloid! I would request Ivan to give us his wisdom on the "prefered" definition but as I recall, it requires a charge on the particles and they must be bigger then atoms! The other constraints, I believe, were that a colloid can not be a solution, dispersion nor suspension. [email protected] -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <[email protected]>
