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Homework Help: Precipitation reaction and supersaturation?

  1. Nov 13, 2012 #1
    I read online that when you add a precipitating agent to a solution it initially becomes superstaurated and you have to take measures to decrease this supersaturation.

    My question is why does it become supersaturated. Really having a hard time understanding this concept.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Nov 13, 2012 #2


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    Staff: Mentor

    You need an activation energy to start nucleation (creating crystals). Sometimes this activation energy is so small, just thermal movements of molecules/ions in solution are enough to start precipitation, sometimes it is much higher and you need some stronger impulse - like a shock wave in the supersaturated solution of sodium acetate in hand warmers.
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