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Is osmosis a form of diffusion?

  1. Jul 3, 2011 #1
    I am confused because I read that a selectively permeable membrane means that it becomes osmosis and that there can't be a selectively permeable membrane for diffusion.

    Or is osmosis just diffusion across a selectively permeable membrane?
  2. jcsd
  3. Jul 7, 2011 #2


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    The way I see it, diffusion is the mechanism by which osmosis can occur in solutions. Diffusion describes the pathway and osmosis describes the destination.
  4. Jul 7, 2011 #3
    The way I understand it is that diffusion is on the macro level, and osmosis is on the microscopic level. Furthermore, diffusion occurs due to a concentration gradient while osmosis can occur due to a concentration of or entropic gradient.
  5. Jul 7, 2011 #4
    Yes, osmosis is a form of diffusion. It involves moving from high concentration to low concentration. The only 'difference' being that osmosis specifically refers to a process in which a solvent goes from a less concentrated solution into a more concentrated one, through a semipermeable membrane, eventually making the concentrations on each side of the membrane equal... Or you could view it as diffusion of the solvent through a membrane.
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