Another fun lab to do without a formal write-up and just before Xmas break is to distill cherry coke. This is a simulation of the distillation of crude oil in the petroleum unit.
Procedure:
Add cherry coke to distilling flask and boiling chip or glass bead; assemble
apparatus for distilling; heat cherry coke gently, especially at beginning;
detect odor of the ester that gives cherry coke its special smell; bubble
some of the gas given off into limewater as test for carbon dioxide; note
the clear fraction(liquid water) and collect in flask and check its density;
stop distillation at this point so as not to char sugars remaining in flask.
Teacher notes: The sweet smelling ester and carbon dioxide are similar to the more volatile fractions which come off in the distillation of crude oil. The water fraction is a good contrast to the dark liquid left in the flask and points up distillation as means of separating components with different boiling points in a mixture. This lab is simple but gives students a known mixture to work with in the lab.
Questions? Comments??
John R Krikau