Melting Point Determination

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Recrystallization is a method used to purify solid organic compounds. Using the recrystallization technique, a solid compound is dissolved in a solvent and the compound slowly crystallizes as the solution cools. Using a filtration technique, a pure solid is produced when the molecules of the impure particles in the compound are excluded from the crystal lattice. After obtaining the pure compound, a melting point determination procedure can be done using a mel-temp device to correctly identify the compound if its identity is unknown. In this experiment, the identity of a given unknown organic solid will be discovered using the methods of recrystallization and melting point determination.

Safety Information
Be sure to add a boiling chip to any liquid before heating it. •Always wear department approved eye goggles at all times. •Long pants and closed toe shoes are required.

Table of Reagents

ReagentMol. Wt. (g/mol)Bp ( ͦ C)Mp ( ͦ C)Density (g/ml) Acetanilide135.17304113-1151.219
Benzoic Acid122.12249121-1231.32
Glucose Pentaacetate120.56295131-1341.245
Cinnamic Acid148.16300133-1341.25
Benzilic Acid228.25180150-1531.08
Adipic Acid146.14337152-1541.36
Salicylic Acid138.123211158-1601.44

Results and Discussion
By using the recrystallization technique, 1.007g of the unknown solid A was successfully purified, leaving 0.527g of pure solid left. This means that in our 1.007g sample of unknown compound A, .480g of impurities were present. During this part of the experiment, the only procedure that did not go according to plan was the amount of hot solvent we added to our compound to dissolve it completely. 10 ml was originally not enough, so more...
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