Separation of the compound ethanol from alcoholic beverages, such as vodka, involves the process of distillation. Distillation is the separation of volatile substances mixed with nonvolatile substances by boiling the mixture to alter the phase of the volatile substance. The researchers used the simple distillation set up to conduct the experiment. 25 ml of The Bar Vodka was used and 7 ml of distillate was collected before a temperature of 95 degrees Celsius was reached. Collected distillate was then subjected to a flammability test to confirm ethanol content. The percent ethanol was computed to be 24%.
Distillation is a method of separation for homogenous mixtures, which are composed of both volatile and nonvolatile substances . It involves the volatile substance to undergo a phase change from a liquid to a gas, and then back to a liquid. The process required for the mixture to be heated at a certain temperature in order for the volatile substance to evaporate and the nonvolatile substance to remain a liquid. As the volatile substance evaporates, it will pass through a condenser, which transforms it back to a liquid and therefore separates the substance from the original mixture. The principle behind this process is the difference in the boiling points of each of the components of the mixture. Boiling point is the temperature at which a liquid becomes a gas. The nonvolatile substance remained as a liquid because of its high boiling point, allowing the volatile substance, which had a low boiling point, to evaporate.
Vodka was the mixture to be distilled in the experiment. Vodka is an alcoholic beverage that contains the compound ethanol (C2H5OH) mixed with water. Ethanol is a compound that belongs to the functional group called alcohols. The distinguishing characteristic of these compounds is the presence of the -OH group that is connected to a hydrocarbon segment . The goal of the experiment is to separate the alcohol content from the vodka and to compute for the percent ethanol content in the beverage.
Results & Discussion
Table 1. Volume of distillate with corresponding temperature readings and
flammability test results
Figure 1. Graph showing temperature versus volume distillate
Table 1 and Figure 1 shows the data gathered after distilling the vodka. The first drop of distillate appeared with a temperature reading of 64 degrees Celsius. 1.0 ml of distillate was collected at a temperature of 82 degrees. The researchers collected 7.0 ml of distillate before the temperature reached 95 degrees. All test tubes were subjected to the flammability test. All except test tube 7 obtained positive results.
Ethanol has a boiling point of 78.5 degrees Celsius while water has a boiling point of 100 degrees Celsius . This explains how the distillate could be inferred to be ethanol. It has a lower boiling point than water, which allows it to evaporate from the vodka and then later condense into the test tubes. It can be seen from the results that the distillate only appeared at a range of 64-90 degrees Celsius, which can support that the distillate is ethanol indeed. One of the possible reasons why there was distillate collected before the theoretical boiling point of ethanol was probably because of other components, such as artificial flavoring, that were included in the vodka which were even more volatile than ethanol.
Another way to figure out if the distillate obtained is ethanol was through subjecting the distillate to a flammability test. Ethanol is a flammable compound, which is why a positive result is expected to confirm if the collected distillate contained the compound. It is seen that the last test tube of the distillate was negative in the flammability test meaning that it...
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3. Bauer, R., Birk, J., & Marks, P. (2009). Introduction to chemistry:A conceptual approach. NY: McGraw-Hill, pp. 22 & 645
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