Organic Chem 255 Lab
M/W 12:30-4:30
Hyejin Cho
12 June 2013
Separation of a Mixture
Abstract:
In this experiment, the three processes of extraction, sublimation and recrystallization will be used to separate a mixture of salicylic acid and naphthalene. The first part of extraction will be to separate the salicylic acid from the naphthalene using diethyl ether and aqueous sodium bicarbonate. The naphthalene will reside in the ether and be the top layer, while the salicylic acid resides in the sodium bicarbonate bottom layer. The two solutions will be separated and a solid crude substance will be collected from both. Then the method of sublimation will purify the naphthalene and the recrystallization will purify the salicylic acid. Melting points of the mixture and both crude and pure substances of each substance will be collected, along with the mass of both. Each mass at the end (actual) will be compared to the theoretical value of the mixture to acquire a percent yield.
Collected Data:
Table 1: Collected Melting Points Throughout “Separation of a Mixture” | Substance | Melting Point (ºC) | Salicylic Acid/Naphthalene mixture | 54.1º - 122.1º | Crude Naphthalene | 71.4º - 72.2º | Crude Salicylic Acid | 157.5º - 175.5º | Pure Naphthalene | 74.8º - 78.0º | Pure Salicylic Acid | |
Table 2: Collected Masses and Theoretical Yields | Substance | Theoretical (Initial) Mass (g) | Actual (Final) Mass (g) | % Yield | Mixture | 0.348 | - | - | Naphthalene | 0.174 | 0.0520 | 29.9% | Salicylic Acid | 0.160 | | |
Conclusion:
From the data collected and the results calculated, I can conclude the percent yield of naphthalene and salicylic acid. (SAL is handwritten in the data tables above). The five melting points for the mixture, crude and pure naphthalene and salicylic acid are also provided above. The final mass of naphthalene was 0.0520g and the theoretical value was 0.174g. I found these values by