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lab stuff

Submitted by eehardy on Tue, 12/04/2018 - 00:20

The first recrystallization had a 30.02% recovery.  While this percent recovery is rather low, this recrystallization likely got rid of a significant amount of impurities that were incorporated in or on the crystals after the crude weight was obtained.  From the first recrystallization to the second recrystallization, a 72.4 3recovery was obtained.  In comparison to the percent recovery obtained from the first recrystallization, this yield is quite high.  This second recrystallization likely got rid of any remaining impurities, and product may have also been lost during the transfer of materials. 

            While the percent recovery of the first recrystallization was low, the melting point obtained from this purified sample, 52-54 °C, was not too far from the standard melting point, 56-57 °C.  The melting point obtained from this first recrystallization was indicative that the sample obtained was impure as the melting point obtained was greater than 2 °C lower than the standard melting point.  However, after the second recrystallization was conducted, the melting point of was 55-57 °C.  The melting point found experimentally aligns nicely with the expected melting point, meaning that these crystals were very pure.  Not only does this second recrystallization affirm the fact that multiple recrystallizations yield purer products, but it also confirms the identity of the extracted product since melting point is a physical property of a substance.