Questions: You will need both the simple and fractional distillation data to ans
ID: 561219 • Letter: Q
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Questions: You will need both the simple and fractional distillation data to answer these questions 1. (2pt) For the GC analysis you were told to inject between 1 and 5 pl of the distillate. Why does the actual volume injected not matter when determining the % toluene? (1pt) From the GC data, examine the purity of the distillates the near the beginning (5 ml), middle (16 ml) and near the end (24 mil) for both the simple and fractional distillations. What can you conclude about the differences between the two distillations? 2. 3 (1pt) what are the obvious differences in the plot of the fractional vs simple distillation? 4. (2pts) Based on the data that you have obtained, which method of distillition provided you with a better separation? Briefly explain how you came to this conclusion from your data. s. (2pts) How did the observed b.p of the first sample of distillate from the fractional distillation compare to the expected boling point of cyclohexane? How did the observed b.p. of the last sample of distillate from the fractional distillation compare to the expected boiling point of toluene? 6. (1pt) How can you determine the relative amounts of components in a mixture by looking at a boiling point versus distillate volume plot? 100Explanation / Answer
1. The actual volume injected does not mater when determining the %toluene as we measure the relative areas and then calculate %toluene in sum total of all the areas. say we have an area of 10 for toluene on GC and the total area of all components in GC was 80. The sum total area is 100. %toluene = 10/100 = 10% in the total volume.
2. In the simple distillation when distilling mixture of components, the chances of getting mixture is much higher. Initial 5 ml would be pure first component, as we move to 16 ml middle region we would get mixture of two components and towards th end 24 ml we would have more of second component in the fractio collected. On the other hand, in fractional distillation the components are neatly separated to the maximum. Therefore, at initial 5 ml and 16 ml middle region we would have only the first component whereas, to the end 24 ml we would have only the second component in the fraction collected.
3. The plot of simple distillation is not smooth, whereas, we see clear boiling point changes in the fractional distillation plot.
4. Fractional distillation would give better result as the two components are clearly separated and we get minimal amount of mixture whereas, in simple we obtain more amount of mixture.
5. The obseved boiling point of cyclohexane matched well with the literature boiling point in case of fractional distillation. Whereas, the last sample boiling point matched with the boiling point of toluene in fractional distillation suggesting that the two components were seperated well.
6. The volume of fraction collected at one boiling point is noted down and the volume of distillate collected at second boiling point is noted down. The percent of first component over the total volume gives the fraction of component present in solution. Same is done for the second component.
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