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3 Cards in this Set
- Front
- Back
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what is the purpose of using recrystallization?
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to purify an impure solid.
its a method of purification that can remove any side products, unconsumed reactants, and other impurities to obtain a pure product. |
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what is the proper solvent choice for recrystallization?
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solvent in which the major component dissolves when the solvent is hot and recrystallizes upon cooling
a desirable solvent is one in which the product will be very soluble at high temperatures, but only slightly or sparingly soluble at room temperature or lower. -the solid to be recrystallized is insoluble in cold solvent but very soluble in boiling solvent -impurities are either insoluble in boiling solvent or moderately soluble in cold solvent -the solvent should have a boiling point in the range of 60-110 so that it will not boil away too quickly, yet allow the crystals to dry rapidly after filtration FIRST YOU MUST FIND A SOLVENT THAT WILL DISSOLVE THE SOLID WHEN HOT, BUT NOT DISSOLVE THE SOLID WHEN COLD. THIS IS BECAUSE CRYSTALLIZATION SHOULD OCCUR WHEN THE SOLUTION IS COOLED |
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how does hot filtration differ from vacuum filtration?
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fluted filter paper is needed for the hot filtration.
fluting allows for a greater surface area of filter paper to come into contact with the filtrate. this allows filtration to occur faster-before the solution has time to cool. vacuum filtration into a buchner funnel is always used to collect and dry the crystals. (filter the hot mixture through a heated, wide-stem or stemless funnel to remove any insoluble impurities collect the crystals by suction filtration, using a buchner funnel |
