Tuesday, 29 January 2013

Crystallization 28/1/13

Crystallization ( refer to slides handout given)

Different from Distillation:
End Product:
Distillation --> solution
Crystallization --> Solute

  • Sodium Chloride ( normal salt solution )  -> CANNOT  ->  same solubility over different temperature.
You need a saturated solution to carry out crystallization.
different from concentrated solution
  • contains the maximum amount of solute dissolved in a given volume of solvent at a particular temperature
  • A concentrated solution: A solution that contains lots of solute dissolved in it.

Speed of Crystallisation And The Size of Crystals Obtained

  • Rapid cooling of saturated solution
        - small and ill-shaped crystals formed
  • Slow evaporation of a cold saturated solution
        - large and well-defined crystals obtained.

graph showing Concentration vs Temperature during Crystallisation



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