Result
Table 1
The crude benzoic acid was a white powdery substance that weighed 1.1 grams. The pure benzoic acid that was recrystallized was white crystals weighing .56 grams. While the solution was cooling small crystals began to form in the solution. It was then vacuum filtered and white crystals were left in the filter and were weighed.
% Yield= (Final mass/Initial mass) X 100%
% Yield (Benzoic acid) = (.56/1.1) X 100%= 55%
% Yield (Benzil) = (.56/1.29) X 100% = 43%
Discussion
In this lab, a mixture of two solids was separated to their individual components by extraction. The yields for benzoic acid (55%) and benzyl (43%) were both low. Because of solubility issues (difficulty dissolving all of the starting material) I know that some of the starting material never left the first flask. After the extraction of the benzoic acid and the benzil, I saw that the two solids were now in the original form we started with ...
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% Yield (Benzoic acid) = (.56/1.1) X 100%= 55%
% Yield (Benzil) = (.56/1.29) X 100% = 43%
Discussion
In this lab, a mixture of two solids was separated to their individual components by extraction. The yields for benzoic acid (55%) and benzyl (43%) were both low. Because of solubility issues (difficulty dissolving all of the starting material) I know that some of the starting material never left the first flask. After the extraction of the benzoic acid and the benzil, I saw that the two solids were now in the original form we started with but they were now separate from each other. It was no longer conglomerate of both. Table 1 shows the percent recoveries of both substances were low and this could have resulted from the all sorts of possible mistakes during the lab. The melting point for benzoic acid matched the melting point for pure benzoic acid. The expected melting points for benzoic acid is 122.4℃, experimental melting point was 120-128℃. The expected melting points for benzil is 94.4℃, but the experimental melting point was found to be 96-98℃. The higher melting point indicates that the crystals formed were not pure. Likewise, the melting point of mixture was found to be 80-113℃, which is slightly lower than the expected melting point. I compared my IR spectrum to the spectrum on the Japanese National Institute of Materials and Chemical research. The peak positions, appearance and relative size all matched exactly, it shows the purity of compounds is high. This experiment left many sources where there could be error. When boiling the benzoic acid and ether, some of the solution may be lost through vaporization even thought stir bar was used. During both of vacuum filtrations, some of the solid may be gotten through the filter. When using the separatory funnel, some of the organic layer may have drained through, or not the entire aqueous layer was drained through Also when using the separatory funnel, it is possible to lose some of the solution when mixing it because this was the first time a separatory funnel was used. Extraction is an important part of organic chemistry. It is used in many fields to trait soil, fuels, and metals. Extraction is a basic procedure in organic chemistry that is necessary to learn and understand. This lab taught many basic aspects of organic chemistry. It included the chemistry of acids and bases, new lab techniques.
Conclusion
The results for the experiment showed that compounds were separated from the mixture (in low yield), but both benzil and benzoic acid were not completely separated from the mixture. While this experiment did not give pure products or good yields, if carried out more carefully, extraction can be a useful way to separate a mixture into individual compounds.
