3B Crystallisation by https://padlet.com/neo_si_lie_charles/zya6liu5mh0q Made with serendipity en-us 2018-01-23 10:02:10 UTC 2018-01-30 13:57:08 UTC hello@padlet.com What type of mixtures can be separated by crystallisation https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225046413 Homogeneous mixtures such as common salt solution and copper sulfate solution can be separated by crystallization.
1) copper sulfate explanation
crystallization occurs by heating water and dissolving copper sulfate into a saturated solution. When the temperature of the saturated solution begins to lower, crystals will begin to form.]]> 2018-01-26 14:02:34 UTC https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225046413 Application of crystallisation https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225050405   Crystallization is also used in the manufacture of other sugars, such as glucose and lactose, in the manufacture of food additives, such as salt, and in the processing of foodstuffs, such as ice cream.]]> 2018-01-26 14:10:58 UTC https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225050405 Using an example of a suitable mixture,describe how can we separate the mixture by the given method. https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225051015
1.  Choose the appropriate solvent-Choosing an appropriate solvent is the important process of crystallisation, as crystallisation works only when a proper solvent is used. It is important to choose a solvent that will not dissolve the substance at room temperature.
2.  Dissolve the impure compound: To do so, place that compound in a test tube.Crush large crystals with a stirring rod to promote dissolving. Add the solvent drop by drop. To remove insoluble, solid impurities, use excess solvent to dilute the solution and filter out the solid impurities at room temperature then evaporate the solvent.
3.  Decolorize the solution- If the solution is colored, add excess solvent and activated charcoal (carbon), and boil the solution for a few minutes
4.  Remove solids by filtration-Filtration can be done by gravity filtration, decantation, or removal of solvent using a pipette.
5.  Crystallize the compound of interest-This step assumes that any colored impurities and insoluble impurities have been removed by appropriate steps above. Remove any excess solvent by boiling it off or blowing it off with a gentle stream of air. Start from a solution saturated with the solute at the boiling point. Allow it to cool slowly to room temperature. Crystallization should begin.
6.  Collect and wash the crystals: To do this, separate the crystals from the ice-cold solvent by filtration. This can be done using the Buchner funnel or by removal of the solvent using a pipette.
7.  Dry the washed product-The crystals can be dried by pressing them gently between sheets of filter paper.  They can also bee ried by spreading them on a porous plate or by placing the crystals in a vacuum desiccator.
]]> 2018-01-26 14:12:16 UTC https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225051015 Precautions to take during crystallization https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225059228 1.Pick the solvent. In the introductory organic lab course, the solvent for recrystallization is usually determined for you.  The criteria used to choose an appropriate recrystallization solvent includes finding a solvent with a high temperature coefficient.  The solvent must not dissolve the compound at low temperatures (that includes room temperature), but must dissolve the compound at high temperatures.  The solute must dissolve in order to rid its lattice of impurities, but must not remain dissolved at room temperature
     

2 . Dissolve the solute.  Remember that the solute should dissolve only when the solvent is heated.  Therefore, the solvent is heated to its boiling point (remember to use boiling stones!) and then slowly added to completely dissolve the solute.  If too much solvent is added, the solution will not be saturated upon cooling and no crystals will form. 
     Dissolving the solute generally involves adding a small volume of hot solvent, swirling the flask (or stirring the solution), and watching to see if the solute dissolves.

3. Filter any solids from the crystals.  If decolorizing carbon was used (as in step 3) or undissolved impurities remain in the hot solution, it is necessary to gravity filter the solution while it is still hot.  Review the information about hot gravity filtration and decolorizing carbon.  Under no circumstances should the hot solution be vacuum filtered with a Buchner funnel.  This leads to premature crystal development as the solution passes through the vacuum filter]]> 2018-01-26 14:27:31 UTC https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225059228 what are the principle involved in Crystallisation? https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225062840 2018-01-26 14:34:18 UTC https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225062840 What are the applications of crystallisation https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225064841 2018-01-26 14:37:47 UTC https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225064841 li_yongxian_jal https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225259306 2018-01-27 02:44:14 UTC https://padlet.com/neo_si_lie_charles/zya6liu5mh0q/wish/225259306