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Understanding Forces in Mixtures & Solution

  1. Sep 12, 2013 #1
    From the wiki article, I understand that Mixtures can be of three types (by homogenity and particle size):
    • Solution (< 1 nanometer)
    • Colloid (between 1 nanometer and 1 micrometer)
    • Suspension (> 1 micrometer)

    1. But if we have two immiscible liquids that each have molecule size particles and mix them mechanically, where do they fit in the definitions?
    It is definitely not a solution since they are immiscible, but it also cann't be a colloid because the particles (actually molecules) are too small to fit for colloid defnition.

    2. What type of intermolecular forces act between the molecules in such immiscible mixture?

  2. jcsd
  3. Sep 14, 2013 #2
    Consider two immiscible liquid mixtures say A and B. By the definition they do not form solution at any proportion. So if we add any amount of A to B or B to A, they do not mix and hence form two separate layer (both have different densities). If we mix them mechanically they won't mix, so we see droplets of A in B (or B in A). If we let them for a while they will separate again in layers. So it is a heterogeneous mixture. The inter-molecular forces will be repulsive in nature.
  4. Sep 14, 2013 #3
    Thanks, this is clear now. So the idea is that immiscible liquids repulse each other and attract only to their own molecules, and thus in steady state they will always form spearate layers or droplets.
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