shabnam Posted June 4, 2007 Share Posted June 4, 2007 Hi.I'm new here.I'm in a bit of a mess with my bio teacher.Here's my question-- Say I take a U-tube and fill one limb with pure water and the other with pure alcohol.They are seperated by a semi-permeable membrane.Shall osmosis take place? My teacher thinks it won't but I believe it will.Could you sort it out. Thanks!!! Link to comment Share on other sites More sharing options...
ecoli Posted June 4, 2007 Share Posted June 4, 2007 Why does your teacher think that it wouldn't? Link to comment Share on other sites More sharing options...
YT2095 Posted June 4, 2007 Share Posted June 4, 2007 is it Absolute alcohol (100% pure) that you`re talking about? or the azeotrope? Link to comment Share on other sites More sharing options...
Klaynos Posted June 4, 2007 Share Posted June 4, 2007 I'd have thought as it is semi-permeable then, yes it will occur because the chemical potential will be different on both sides... Link to comment Share on other sites More sharing options...
shabnam Posted June 5, 2007 Author Share Posted June 5, 2007 He thinks that because the solvents are different they shouldn't get through. But my argument is that as the two liquids are soluble in each other osmosis should occur.But I can't convince him.I'm trying to be more technical... Thanks Link to comment Share on other sites More sharing options...
shabnam Posted June 5, 2007 Author Share Posted June 5, 2007 Its pure alcohol. er....whats an azeotrope? Link to comment Share on other sites More sharing options...
shabnam Posted June 5, 2007 Author Share Posted June 5, 2007 I'd have thought as it is semi-permeable then, yes it will occur because the chemical potential will be different on both sides... OK. Think I get you.Thanks. But I'm not really confident about being able to explain chemical potential.Could you help me out? Link to comment Share on other sites More sharing options...
Klaynos Posted June 5, 2007 Share Posted June 5, 2007 How permeable is semi-permeable? What's the biggest thing it'll let through? That's the real question here. tbh despite having an exam on statistical mechanics yesterday about this it's probably my most physics subject The original gibbs statement was: If to any homogeneous mass in a state of hydrostatic stress we suppose an infinitesimal quantity of any substance to be added, the mass remaining homogeneous and its entropy and volume remaining unchanged, the increase of the energy of the mass divided by the quantity of the substance added is the potential for that substance in the mass considered. But what this means is a bit more complicated. I've always seen it as the lowest energy level that a system wants to tend to. It's used with the number of molecules in the statistical mechanics energy of a system to allow for open system. If you minimise the gibbs free energy you can show that a requirement of a 2 level system for a minimal gibbs (so in equilibrium) the mew's of the 2 systems must be the same. Link to comment Share on other sites More sharing options...
John Cuthber Posted June 9, 2007 Share Posted June 9, 2007 If the membrane will let both alcohol and water through then ,in the log run, all you will get is a mixture of the 2 due to diffusion. Link to comment Share on other sites More sharing options...
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