How far should you insert the thermometer into the distillation head?

Which of these funnels would you use in suction filtration?  

The thermometer in a distillation setup should measure the temperature of

At what temperature do you expect the 75 mole percent cyclohexane in water mixture to boil?  

Why does the caffeine transfer from the aqueous phase into the organic phase?

The key difference between simple and fractional distillation is the presence of

The isolated organic layer will be contaminated by water. How would you get rid of excess water?

The boiling point of a compound, determined by distillation, is one of the physical properties that can be used to confirm its identity.

How does methanol-water temperature plot differ from the glycerol-water temperature vs volume plot that you observed during your experiment?  

what is the organic solvent used in your extraction of caffeine ?