Question

1. Assemble the glassware for fractional distillation according to the diagram and discussion above. Make certain that all joints are secure and that the apparatus is appropriately supported. Remember to allow for space below the distillation flask for the heating mantle and below the receiving flask for an ice bath.

2. Pay extra attention to the positioning of the bulb of the thermometer as mentioned in the introduction. It is critical that the thermometer be positioned correctly for accurate temperature measurement.

3. Using a graduated cylinder, carefully measure 10.0 mL DI water and add it to an Erlenmeyer flask.

4. Carefully measure the appropriate volume of ethanol (as calculated in the pre-laboratory exercises) and add it to the flask containing the DI water. Swirl to mix.

5. Reserve ~5 mL of the mixture for boiling point analysis, and set aside.

6. Transfer the remaining mixture to the distillation flask and check to be sure all connections are secure. DO NOT FORGET TO ADD A BOILING CHIP TO PREVENT BUMPING.

7. Turn on the heating mantle to something mid-range (5-6) and check to be sure it starts to heat up. (Warning: once the temperature begins to rise, the glassware will become veryhot, so be careful not to burn yourself.)

8. Record the starting temperature from the thermometer in your lab notebook and make a note of the starting time.

9. Watch for vapor to start forming on the inside of the top of the distillation flask (this may take ~10 minutes).

10. Once the mixture starts to boil, wrap the distillation flask loosely with a piece of aluminum foil in order to provide some insulation and keep the heat inside the flask. If you are not seeing vapor and condensation climbing up through the fractionating column within ~30 min., turn up the dial on the heating mantle 1 or 2 marks.

11. Once you see liquid start to condense at the top of the condenser, add an ice bath under the receiving flask.

12. Once the temperature begins to climb, start making a table of temperature vs. time until you have collected approximately 10 mL of distillate.

13. Note the time when the first drop of distillate falls into the receiving flask.

14. Once you have ~10 mL of distillate (you will have to do your best to guess this volume,

    based on the size of the receiving flask), turn off the heat and allow the system to cool.

15. DO NOT DISTILL TO DRYNESS.

16. Using a graduated cylinder, carefully measure the volume of distillate.

17. Once everything is sufficiently cool, carefully disassemble the apparatus, record all

    observations, and clean the glassware.

18. Perform boiling point analysis of the starting mixture (set aside in #5 above) and the final

    distillate you collected according to the semi-microscale procedure provided in the Boiling Point Analysis document on Blackboard. Use two small or medium test tubes as the vessels for the liquids you’re testing. (Do not worry about the various thermometercorrections discussed in the Boiling Point document.)

19. Record your results in your lab notebook.
20. All solutions can be disposed of down the sink.

Come up with at least two aspects of the protocol that are NOT Green.

Answer 1

1. All solutions can be disposed of down the sink. this step is not green since the harmful chemicals are dumped in the sink which will eventually harm the environment and living organisms.

2.Turn on the heating mantle to something mid-range (5-6) and check to be sure it starts to heat up.This step is not energy efficient since heat in form of fire is used instead using some other alternatives such as microwave heating which is both energy efficient and less time consuming.