Friday, September 25, 2009
The grading statistics for CHEM 233 are now posted on the Grades Fall 2009 page. I was hesitant to post these so early in the semester, but I did anyway since there have been several questions regarding lab report scores. Please do not over analyze these stats; currently, they only reflect the scores of the first two lab reports. They are meant to give you an approximate idea of how your scores compare to the rest of the class and how your TA's section average compares with the others. Remember, initially all sections are normalized to a 70% average (for lab reports only), which means that if your TA's lab report average is below 70% every student's lab report average will be raised until the section average is 70%. Likewise, if your TA's average is above 70%, every student's lab report average will be lowered until the section average is 70%. The stats will, of course, become more informational as more scores are added and when the scores of those students who have withdrawn have been removed. If you would like an individual detailed report of your grades, which will include your normalized lab report score, please stop by my office during office hours and I'd be happy to print one out for yo
Tuesday, September 22, 2009
This semester I am making a slight change to the steam distillation experiment (Lab 5). In addition to isolating (S)-(+)-carvone from caraway seeds, you are also going to isolate (R)-(-)-carvone from spearmint leaves. For more details on this modification download the file "steamdist_modification.pdf" on the File Sharing page. You will work in groups of two. One member of the group will isolate (S)-(+)-carvone from caraway seeds, the other will isolate (R)-(-)-carvone from ground up spearmint leaves. The spearmint leaves I purchased are dried. Since I'm not sure how much carvone is present per gram of dried leaves, we may need to increase the starting mass of spearmint leaves. We'll see how the first lab section goes and then modify as necessary. Good luck. It should be a very fragrant lab.