Download Distillation - Experiment 3 - Organic Chemistry Laboratory | CHE 276 and more Lab Reports Organic Chemistry in PDF only on Docsity! (CHE 276) Organic Chemistry Lab Fall 2008 Experiment 3: Distillation Answers to Questions: Answers to questions should be typed and submitted in Appendix C of your Lab Report. Supporting figures, structures, and calculations, if any, may be neatly hand written. 1. What distillation method would you use to separate a 1:1 mixture of ethyl acetate and acetone? Explain your reasoning. (2) fractional distillation: Their boiling points differ by only 20°C (ethyl acetate boils at 77°C; acetone boils at 56°C) 2. Compound A distills at 100°C at 760 mm Hg. How will the boiling point of A change if the distillation is conducted at 725 mm Hg? Clearly explain your reasonong. (3) the boiling point of compound A will be lower. Since a compound boils at the point where the vapor pressur of the liquid is equal to the atmospheric pressure, lowering the atmospheric pressure to 725 mmHg will allow A to boil at a lower temp. 3. A student carried out a simple distillation on a compound known to boil at 124°C. The boiling point observed was 116-117°C. Subsequent analysis showed that the distilled compound was pure. The thermometer used in the distillation had also been calibrated correctly. What procedural error might the student have made in setting up the distillation apparatus? (2) the thermometer was improperly placed – it was placed too high. 4. The figure below describes the distillation behavior of a mixture of A and B. If the mole fraction of B in the liquid is 0.65, what is the composition of B in the vapor above the liquid? What will be the reading on the thermometer at this point? What is the boiling point of pure compound B? %B %A 20 6040 80 1000 0100 80 4060 20 percentage composition T (°C) 40 50 60 70 80 90 40 50 60 70 80 90 b.p. of pure B thermometer reading (1) The vapor composition will be approximately 70%A & 20%B (1) When the mixture of 65%B/35%A begins to boil the reading on the thermometer is 65°C (1) The boiling point of pure B is 80°C
