Class admin Turn in revision exercise #2 Pick up and fill out TA evaluation forms Pink = Adrienne White = Khadine

Oxygen uptake by Co(salen) Notes on part 2 of lab: Bring stopwatch Depending on yields, may carry out project as a group

Last week: prepared Co(salen) Co(salen) can bind oxygen, just like the biological heme molecule easy hard versus

Oxygen binding depends on Co environment Mercury view In crystals: Solvated: Co(salen) exists with Co in a 4, 5, or 6 coordinate site Solvated Co(salen) will bind O2 when it is 5 or 6 coordinate

Experimental apparatus Which way will the water move? How many SF’s to report?

Graphing data What is our: dependent variable independent variable Which one belongs on which axis? How do we best extrapolate to infinite time?

Revision exercise #2 Goal: submit an improved version of your lab 6 (MIMT) report Take your report to the University Writing Center for feedback in paper and electronic form [computers available there] You can skip the “Questions” section in your re-write – please focus on the report text (Title, Introduction, Data Analysis, Discussion) Turn in your original and revised lab reports to me, with UWC comments if they are available Due date: Class period on April 30th (two weeks from today) Note: no other lab report is due that week Hours for University Writing Center: Mon-Wed: 10 AM – 10 PM Thur: 10 AM – 7 PM Sun: 2 PM – 7 PM Web site: http://writingprogram.hfa.umass.edu/writingcenter/writingcenter.asp Located in the Learning Commons of the WE DuBois Library

Writing exercise Experimental assignment Communication error My intent: spend extra time revising the writing (conciseness, organization, flow, transitions, paragraph divisions, grammar, readability, style) Student interpretation: GRAMMAR Grading – positive points Will reward effort Will reward accomplishment

Evaluation of writing in course How useful were the lectures on writing Extremely Very Reasonably Somewhat Not at all How useful were the TA comments on writing on the lab reports How useful were the instructor comments on lab report 5 How useful were the UWC comments on writing the lab reports Comments for improvement on the writing aspects of Chem242

NA exercise 25 pts / problem -10 if SF errors -5 unit errors 25 pts for group work (consistency in answers) Positive points only. (Divide points by 10, score will be added to lab 8 grade)

Experimental Recrystallization Anaerobic environment Solvent temperature – entropic arguments Evaporation – effect on purity? Solvent choice (high relative solubility for impurities) Recrystallization should be done relatively slowly Anaerobic environment vacuum pump / fill cycles

Coordination of metals in inorganic compounds Coordination Number “dentate”