The Purity and Purification of Solids Recrystallization Lab Essay

1636 Words Mar 6th, 2013 7 Pages
The Purity and Purification of Solids

In this experiment, impure adipic acid is purified though recrystallization. The impure adipic acid is dissolved in a solvent. After cooling it is ran through a vacuum filter to separate any moisture. The dry crystals are then weight for percent yield and the melting point range is taken to test the purity. There were two different trials ran in this experiment. The difference between the two was the addition of charcoal in the initial step to remove color impurities. For part A (without charcoal) the initial impure weight was 1.0256g. After the filtration, the final pure product weighted 0.6063g which is a 59.17% yield. The Melting point range for part A was 151.1°C
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All steps after wards should continue the same way as part A.

RESULTS AND DISCUSSION | Weight Used | Final Weight | % yield | Melting Point | Part A (no charcoal) | 1.0256g | 0.6063g | 59.17% | 152.1°C – 154.9°C | Part B (charcoal) | 1.0008g | 0.4631g | 46.27% | 153.0°C – 155.0°C | Impure Adipic Acid | N/A | N/A | N/A | 151.1°C – 156.8°C |

The initial weight of the impure adipic acid for part A (without charcoal) was 1.0256g. After the purification the weight of the crystal that was yielded from the purification was 0.6063g, which came out to be a 59.17 percent yield. When the initial impure adipic acid was made into a slurry, it created a light blue color throughout the hot liquid. This color is the color of dissolved impurities mixed with the adipic acid within the hot water. When the hot liquid was transferred from the hot plate through the filter, the filter paper clearly showed where there were traces of the mixture still absorbed within the filter paper. This made it easy to identify and use a pipette and boiling water to wash most of the mixture through. This was not true for part B where the initial weight was 1.0008g and after the purification was 0.4631g of crystal was yielded. The percent yield was 46.27g, much lower than part A. This could be because of the charcoal that was added. It removed the color from the hot liquid so it was not possible to identify where the hot liquid was absorbed to the filter paper. That is one possible reason

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