granpa Posted January 5, 2015 Share Posted January 5, 2015 Water is referred to as the universal solvent because it can dissolve more substances and in greater quantity than any other solvent. Yet, paradoxically, 99.9% of the earth is insoluble in water. Silicate rocks dont dissolve in water for the same reason that they are amorphous. They are a polymers. Chain silicates. Geopolymers. (cf. silicone). If they are allowed to cool slowly, these chain silicates can fold up into regular crystal structures but they are still long chains of covalently bonded atoms. On the other hand, if it cools too quickly then the result is an amorphous glass, like obsidian. Solid organic compounds consisting of ordinary small molecules tend to be crystalline, that is, the molecules pack themselves in regular three-dimensional arrays. Polymers are different; they can be amorphous (totally lacking positional order on the molecular scale) or semicrystalline (containing both crystalline and amorphous regions in the same sample). Semicrystalline polymers have true melting temperatures at which the ordered regions break up and become disordered. In contrast, the amorphous regions soften over a relatively wide temperature range (always lower than Tm) known as the glass transition (Tg). Fully amorphous polymers do not exhibit Tm, of course, but all polymers exhibit Tg. Carbonates are similar to silicates but do not form polymers. This is why caves tend to form in carbonate rock. https://en.wikipedia.org/wiki/Carbonate#Structure_and_bonding Link to comment Share on other sites More sharing options...
studiot Posted January 5, 2015 Share Posted January 5, 2015 Water is referred to as the universal solvent because it can dissolve more substances and in greater quantity than any other solvent. What is your basis for this claim? Link to comment Share on other sites More sharing options...
Bignose Posted January 5, 2015 Share Posted January 5, 2015 So, what's your point? You don't want water to be known casually or colloquially as 'a universal solvent' anymore? I think anyone who seriously needs to know about solvents looks up solubilities as needed. I don't think anyone seriously thinks that water has to dissolve everything... Link to comment Share on other sites More sharing options...
Strange Posted January 5, 2015 Share Posted January 5, 2015 I thought this sounded familiar: http://www.scienceforums.net/topic/82542-universal-solvent/ And: http://www.thescienceforum.com/earth-sciences/43229-universal-solvent.html 1 Link to comment Share on other sites More sharing options...
hypervalent_iodine Posted January 6, 2015 Share Posted January 6, 2015 ! Moderator Note Well spotted. Ridiculous thread closed. Link to comment Share on other sites More sharing options...
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