Hi, my name is Rachel. I will be demonstrating the steps required for successful recrystallization. So, let's get started.
For this experiment, we're using water as our solvent, which I've already preheated. Now let's add boiling chips, followed by the impure compound. In this step, we are trying to dissolve the compound in the minimal amount of hot solvent. We'll add the hot solvent in small portions to our flask. After each addition swirl the flask and bring it to a boil before adding more. We only want to add enough hot solvent to fully dissolve our compound. Some of the impurities may not dissolve. At this point, we need to filter out the insoluble impurities from the solution while keeping the solution hot. To speed up the filtration, we fold the folder paper to increase the surface area of filtration. It is crucial to keep the entire filtration system hot to prevent premature crystallization. To do so, add a small amount of hot solvent to keep the filter paper in place. Put the system on the hotplate, the solvent added insures it remains hot. Now we are ready to filter our solution. Wash the flask with a small amount of hot solvent to help remove any remaining compound. Rinse the filter paper one more time to wash any solution trapped in the filter. And then set it to the side. At this point, we've successfully separated the insoluble impurities. Remove the flask with the filtered solution from the heat and allow it to cool slowly. Although the formation of crystals takes some time, we've sped up the footage to demonstrate the process. While the crystals form the soluble impurities remain in the solution. We are now ready to separate the crystals by vacuum filtration. Placing a trap between the filter flask and the vacuum line helps protect the vacuum system. Now open the vacuum. To insure that they're sealed to the funnel, wet the filter paper with a small amount of cool solvent. Rinse the flask with cool solvent then transfer it to the filter. We can wash the crystals with the small amount of cool solvent. We have finally isolated our purified crystals from the soluble impurities in the solvent. All that's left is to simply let them dry. I hope this demonstration on recrystallization will be useful.And Good luck in lab!
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