Crystallisation Potassium nitrate #Exp11

WHAT IS INCLUDED IN THE KIT

• 250g Potassium Nitrate
• 2 Petri dishes
• Not included: Distilled Water and Beaker

DETAILED STEP-BY-STEP

• Prepare a solution of 250ml of water and 100g of nitrate in the saucepan where it is to be heated. Stir well and wait until it comes to the boil, and when it is well dissolved, set it aside.
• Once our solution is ready, add some to the Petri dish.
• Leave to stand for 10-15 minutes, after which time you will see the crystals form.

TECHNICAL EXPLANATION

This is the easiest and most effective way to purify complex compounds. It involves dissolving the impurity in the smallest possible amount of a suitable solvent and heating. Under these conditions, a complete solution is formed which, when cooled, becomes supersaturated and crystallisation occurs. As the solution cools, the solubility of the nitrate decreases and crystals will form in the Petri dish.