Mass Of Benzocaine And Benzoic Acid Mixtures
The obtained mass of benzocaine and benzoic acid mixture was measured to be 2.075 grams. Following being dried for a week the mass of benzocaine was recorded to be 0.250 grams, and benzoic acid was recorded to be 0.600 grams. The melting point range of benzocaine was measured to be 89.5°C-91.5°C, while benzoic acid’s melting point range was measured to be 129°C-131.3°C. The percent mass recovered was calculated to be 40.96% for the experiment. Table 1 illustrates the collected information.
Starting Mass of Benzocaine/Benzoic Acid: 2.075 g
Mass of Benzocaine recovered: 0.250 g
Mass of Benzoic Acid recovered: 0.600 g
Percent Mass Recovered: "(.250 g+ 0.600 g)" /"2.075" " × 100 = 40.96%"
Recovered Benzocaine MP: 89.5°C-91.5°C
Recovered Benzoic …show more content…
Acid MP: 129°C-131.3°C
Table 1
Discussion
In this lab, we conducted a liquid-liquid extraction to separated two immiscible liquids based on solubility.
We started by dissolving the mixture of benzocaine/benzoic acid in dichloromethane. 6 M of hydrochloric acid was added to the dissolved solution to create an acidic layer. Benzoic acid remained in dichloromethane while the benzocaine moved into the acid layer. To extract the benzocaine, 6 M of sodium hydroxide was added and the solution was filtrated through a hot vacuum filtration. The crystals were allowed to thoroughly dry for a week and the mass and melting point were recorded. To extract benzoic acid, 3 M of sodium hydroxide was added to the dichloromethane solution, and was then acidified with 6 M of hydrochloric acid. Hot filtration was conducted to extract the benzoic acid crystals. They were allowed to dry for a week and the mass and melting point were recorded.
Experimental Errors Ideally, when I add up the mass of benzoic acid and benzocaine I should recover 2.075 grams, but this is not the case. Possible sources of error include some of the aqueous layer seeping into the dichloromethane layer and some of the dichloromethane layer seeping into the aqueous layer. Using separation there is no 100% way to ensure that you get all of just one substance. Another potential source of error could be the result of some crystals being too close to the edge of the filter paper and being lost in the filtration
funnel.
Starting Mass of Benzocaine/Benzoic Acid: 2.075 g
Mass of Benzocaine recovered: 0.250 g
Mass of Benzoic Acid recovered: 0.600 g
Percent Mass Recovered: "(.250 g+ 0.600 g)" /"2.075" " × 100 = 40.96%"
Recovered Benzocaine MP: 89.5°C-91.5°C
Recovered Benzoic …show more content…
Acid MP: 129°C-131.3°C
Table 1
Discussion
In this lab, we conducted a liquid-liquid extraction to separated two immiscible liquids based on solubility.
We started by dissolving the mixture of benzocaine/benzoic acid in dichloromethane. 6 M of hydrochloric acid was added to the dissolved solution to create an acidic layer. Benzoic acid remained in dichloromethane while the benzocaine moved into the acid layer. To extract the benzocaine, 6 M of sodium hydroxide was added and the solution was filtrated through a hot vacuum filtration. The crystals were allowed to thoroughly dry for a week and the mass and melting point were recorded. To extract benzoic acid, 3 M of sodium hydroxide was added to the dichloromethane solution, and was then acidified with 6 M of hydrochloric acid. Hot filtration was conducted to extract the benzoic acid crystals. They were allowed to dry for a week and the mass and melting point were recorded.
Experimental Errors Ideally, when I add up the mass of benzoic acid and benzocaine I should recover 2.075 grams, but this is not the case. Possible sources of error include some of the aqueous layer seeping into the dichloromethane layer and some of the dichloromethane layer seeping into the aqueous layer. Using separation there is no 100% way to ensure that you get all of just one substance. Another potential source of error could be the result of some crystals being too close to the edge of the filter paper and being lost in the filtration
funnel.