18.1 Instant Gold-- A Saturated Solution

Chemical Concepts Demonstrated: Saturation, recrystallization


Pb(NO3)2 and KI solutions are mixed to form a precipitatate of PbI2.

The precipitate is dissolved in hot water and filtered into a bottle.


    When the bottle is shaken, the solution on the inside of the bottle turns into a swirling mass of golden flakes.


    A saturated solution of a solid solute and liquid solvent should be able to hold no more solid within the liquid.

    A saturated solution, by its very nature, is holding no more solute than it should be able to.  Upon agitation, the crystals in solution move past each other.  In this case, the movement comes in the form of a vortex of gold particles.