INTRODUCTION Distillation is a technique widely used in organic chemistry for separating compounds based on differences in their boiling points. The experiment is divided into two parts: simple distillation, an easy set-up where a solution or a mixture of substances with different volatility is separated through exposure heat; and fractional distillation, which under goes a series of evaporation and condensation process to purify more complex mixtures. Raoult and Dalton Law are the two principles involving with this experiment. The former states that the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent at the same temperature scaled by the mole fraction of the solvent present. While the latter states that the total pressure of a gas in a container is the sum of the partial pressures of the individual gases in the container. In this experiment, the group performed a fractional distillation set-up. At the end of the day, they were able to attain the following objectives: differentiate simple from fractional distillation, separate the components of an alcoholic beverage and calculate the percentage of ethanol in a beverage.

EXPERIMENTAL
A. Compounds tested The compound or sample used in this experiment was vodka (alcohol). Vodka (35%–50%) was originally distilled from fermented wheat mash but now also made from a mash of rye, corn, or potatoes. In chemistry, an alcohol is an organic compound in which the hydroxyl functional group (-O H) is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms. The sample we used in this experiment was vodka. Some other types of alcohol include: wines (8-14%), beer (3-10%), spirits (20-70%), and fortified wines (16-22%). All of which have distinct alcoholic concentrations.

B. Procedure 1. Designation of Simple and Fractional Distillation among even and odd groups The distillation set-up was assembled by the odd-numbered groups; whereas, fractional distillation set-up was assembled by the even numbered groups. 2. Preparation of the equipment needed The experimenters prepared and numbered test tubes with a calibration down to 0.5 mL mark. 3. Application of vodka sample Then, they placed 3 pieces of boiling stones into a quick-fit distilling flask and included a 30 mL of vodka sample. 4. Heating the flask With the use of an alcohol lamp, they heated the flask in a rotating fashion until the vodka started to boil. After which, the temperature was recorded at the first drop of the distillate. 5. Recording of the temperatures After the temperature reached about 180°, the temperatures of each test tubes with the distillates were noted after a 0.5 mL mark. 6. Test using flame The first test tube with 3-5 drops of the distillate placed on a watch glass was subjected to a flammability test. 7. Repeat the process Repeat the steps on the distillate from the last test tube.

RESULTS AND DISCUSSION The figure below shows the relationship of temperature (°C) to the volume of vapor collected from the sample. The highlighted part indicates where the concentration of alcohol is strongest.

Figure 1.1 Relationship of Temperature (°C) vs. volume (mL) An increase in temperature for 0.50 ml of collected vapor describes the table below. When the temperature becomes constant and eminent a constant slope in the graph, it confirms the presence of ethanol in the sample wherein it is most concentrated. There is a presence of alcohol when it produces a flame during flammability test. The alcohol beverage in the experiment shows a blue flame. When there is a presence of flame, blue color is produced. On the other hand, if there is no flame produced, ethanol is not present in the sample test tube.

Test Tube | Volume (ml) | Temperature (°C) | 1 | 0.5 ml | 76 °C | 2 | 1.0 ml | 76 °C | 3 | 1.5 ml | 77 °C | 4 | 2.0 ml | 78 °C | 5 | 2.5 ml | 78 °C | 6 | 3.0 ml | 78 °C | 7 | 3.5 ml | 78 °C | 8 | 4.0 ml | 78 °C | 9 | 4.5 ml | 78 °C | 10 | 5.0 ml | 78 °C | 11 | 5.5 ml | 78 °C | 12 | 6.0 ml | 78 °C | 13 | 6.5 ml | 79 °C | 14 | 7.0 ml | 79 °C | 15 | 7.5 ml | 79 °C | 16 | 8.0 ml | 80 °C | 17 | 8.5 ml | 80 °C | 18 | 9.0 ml | 81 °C | 19 | 9.5 ml | 82 °C | 20 | 10.0 ml | 83 °C | 21 | 10.5 ml | 84 °C | 22 | 11.0 ml | 87 °C | 23 | 11.5 ml | 89 °C | 24 | 12.0 ml | 91 °C | 25 | 12.5 ml | 92 °C | 26 | 13.0 ml | 93 °C | 27 | 13.5 ml | 94 °C | 28 | 14.0 ml | 94 °C | 29 | 14.5 ml | 96 °C | 30 | 15.0 ml | 96 °C |
Table 1.1 Temperature and volume readings

Percentage of ethanol (computations):

Total volume of alcohol in the distillate: 4.5 mL
Total volume of alcohol used: 30 mL

% Ethanol = total volume of alcohol in distillate / total volume of alcohol used = 4.50 mL x 100 % 30.0 mL = 15.0 %

1st inflection: 0.5 mL x 9 = 4.5 mL
2nd inflection: 3.0 mL x 0.5 = 15.0 mL

Percentage loss (computations):

Total volume of alcohol used: 30 mL
Total volume loss: 30 mL (original) – 28 mL (recovered) = 2.0 mL
Total volume recovered: 15 mL + 13 mL = 28.0 mL

% loss = amount sample lost x 100% volume alcohol used = 2.0 mL x 100% 30 mL = 6.67%

The next figure shows the parts and functions of a distilling flask.
Figure 1.2 Parts and Functions of a Fractional distillation

1. Distillation flask: The distillation flask is a round-bottom flask and is sometimes referred to as “the pot”.
2. Distilling adapter: The adapter connects the distillation flask, the condenser, and the thermometer.
3. Condenser. The condenser cools the vapor to a liquid and directs this condensate to the receiving flask.
4. Receiving flask. The container to collect the condensed vapor is called the receiver.
5. Thermometer – The device to record the temperature.
6. Adapter – It is a connector for joining parts or devices having different sizes

REFERENCES
From the book 1. Whitten, K., Davis, R., Peck, L. & Stanley, G. (2010). Chemistry. Brooks/Cole: Cengage Learning.

From the internet 1. Answers.com. (n.d.) Retrieve July 11, 2009, fromhttp://www.answers.com/topic/distillation 2. Scribd.com. (n.d.) Retrieve July 11, 2009, fromwww.scribd.com/doc/6663/D202ch 3. Alcohol contents.com (n.d.) Retrieve August 5, 2008, from http://egon.cheme.cmu.edu/Papers/Caballero_Optimization_of_Distillation_Processes.pdf 4. Chemwiki.com (n.d.) Retrieve January 10, 2006, from http://www.chem.wisc.edu/courses/342/Fall2006/Experiment_2.pdf