MU, Chemistry 8160 - Organic Spectroscopy - Fall 2010
NUMBER OF TESTS TAKEN: 13 enrolled E4Q1 E4Q2 E4Q3 E4Q4 E4Q5 E4 Assig. COURSE Max. Poss. 15.0 15.0 20.0 20.0 30.0 100.0 200.0 100.0% Average 11.2 6.5 18.4 12.2 60.4 182.4 75.6% Std. Dev. 3.0 5.3 2.3 5.7 13.9 12.6 6.8% Minimum 6.0 0.0 12.0 0.0 2.0 42.5 156.6 63.6% Maximum 15.0 15.0 20.0 20.0 23.0 86.3 196.6 87.7% Q1 went very well, Q3 went much better than expected, Q2 and Q5 went so-so, and Q4 was quite a bust. Q4 was not counted and your final grade is your percentage based on Q1 - Q3 & Q5. Q4 was not counted because the average of those students who worked Q4 was below the acceptable threshold of 50%. The averages of Q2 and Q5 are above 50% considering the students who worked the problems. Regarding Q2: Most got the C-signals of ethyl acetoacetate correctly assigned and that was nice to see. There was some confusion about the minor component (one of the two a priori possible enols). Regarding Q5: We dealt with several pyridines in Assignment A10 and I had hoped that would make nicotinic acid a fair question. To do this right one must know that OH groups can be all the way down to 2500 1/cm in aromatic acids! Whether the acid is in the 2- or 3-position is a little hard, but it is easy to exclude the acid in the 4-position. Q4 looks very complicated. The trick is not to start with the analysis of the spectra until after you decided what to look for!! You are half way there once you understand that the CH is a chiral center and that its chem. shift and coupling are key. The CH must be coupled to NH in all isomers and it is coupled to only one CH2 in two isomers. The rest is chem. shift considerations. The average for Exam #4 is 60.4%; a little lower than expected but acceptable considering the comprehensive nature of the final. The course average was determined as described in the syllabus (your 10 best assignments for a maximum of 200 points, 3 tests @ 100 points max. each, the final counts twice). The course average is 75.4% and that is quite perfect from my perspective. The average deviation for the course is 7% and that also is very much in the desired range. Twelve students are above 65%, one is at 64% and close to 65%, and no "C" grades are given. "A" for average or better (8) and "B" otherwise (5).