Determination of the Alcohol Content of Wine by Fractional Distillation Lab Report PDF

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Experiment 1- Determination of the Alcohol Content of Wine by Fractional Distillation Lab Report, CHEM 141 Fall 2020...

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Deniz Dutton Ben Rose Exp. 1 Post-Lab 9/15/20 Determination of Alcohol content of Wine by Fractional Distillation Introduction: Distillation has been practiced for thousands of years. One modern use of distillation is the conversion of crude oil into a more pure form- gasoline. Distillation works by taking advantage of the different boiling points of substances. Sometimes a substance will boil at a lower temperature than usual when in solution with a substance with a much lower boiling point, such as in an ethanol and water mixture. For this reason a fractional distillation apparatus must be used to effectively separate the substances. Substances with higher boiling points will condenser sooner as they move up the fractionating column and away from a heat source, leaving behind the vapors of the other substance of interest which can be distilled. In this experiment, the ethanol content of table wine was isolated from the water content using a fractional distillation apparatus, and the content compared to the percentage on the label of the wine. Methods: 50 mL of wine were put in a round bottom flask and heated at a temperature up to 100 degrees C. Since ethanol has a lower boiling point, it vaporized more quickly and traveled up the fractionating column, along with some water vapor. However, the water condensed first as it moved away from the heat source, leaving the ethanol to continue up the column, through the condenser, and end up as liquid distillate in a 10mL graduated cylinder. In order to graph a distillation curve for the experiment, it was necessary to write down the temperature displayed on a thermometer inserted into the fractionating column for every milliliter of distillate collected. Data and results:

0 mL

17 C

1 mL

64 C

2 mL

67 C

3 mL

68 C

4 mL

68 C

5 mL

68 C

6 mL

69 C

7 mL

70 C

8 mL

74 C

9 mL

79 C

10 mL

83 C

11 mL

87 C

12 mL

87 C

13 mL

87 C

14 mL

88 C

Figure 1: Raw data from experiment. Temperature noted for every 1 mL of ethanol collected.

Figure 2: Temperature vs. volume graph for the fractional distillation of ethanol from table wine. Discussion: Based on the graph, the amount of ethanol isolated was between 7 and 11 mL, indicating that the wine sample contained between 14% and 22% ethanol. The true ethanol content of the wine is not known, so it is difficult to determine the accuracy of the experimentally determined ethanol content. There was significant opportunity for error in this experiment. The thermometer was calibrated incorrectly so that it registered temperatures as about 10 degrees less than what they actually were, hence ethanol appearing to boil at 68 degrees rather than 78. Because of this, the distillate was contaminated with water because 100 degrees Celsius was reached without the thermometer registering it, and the experiment continued for many minutes with water vapor

entering the condenser. However, by looking at the data, it can be determined what the actual ethanol content was before this happened, by considering only the data points before the boiling point of water was reached and after the boiling point of ethanol....