Chemical EquilibriaCH302 Random Musings, April 7, 20051. The exam 2 average for the class was about 75%, which, considering the increased number of questionscompared to last year for the same exam (36 questions instead of 30), is quite good. Some of you might notthink this given your performance, but actually the overall testing was what I would expect from a class with thiscapability.2. I have already thrown out two questions. One was the molality question about ranking colligative propertieswhich was mis-programmed in the HW Service. So everyone received credit. The second is the question oneffective molality. It occurred to me that while I taught the individual concepts of molality and distinguishingthe effective concentration of ionic compounds in water, I did not teach then jointly and hence the idea of aneffective molality was not fair for testing. So everyone received credit for that one. I think the rest of thequestions were reasonable. Probably the biggest e-mailed concern was not being able to identify AlCl3 as ionicand PCl3 as a polar molecule. Also, almost everyone misread the vapor pressure calculation, and not seeing thephrase “by weight,” assumed the ratio was a mole fraction. 3. Curving the grades using extra credit. So how do I make it up to you that this was a more challenging examthan last year, and that those students got a higher average score even though there is no way they are better thanyou? I could just give back the points, maybe give everyone ten points to raise the test average to about a 78.But that wouldn’t be fair to the your deep inner psyches that yearn to earn your grades. So instead I will offertwo additional extra credit opportunities, bringing your extra credit point totals to a maximum of 5% of thecourse grade. Furthermore, I will allow these points to be used for any grading scheme in the class. In effect, Iam lowering the cutoffs for everything by exactly half a letter grade. See the table below for the corresponding4. The new grade cutoffs that honors your inner psyches. Here is a handy table to use as your guide for where Iwill draw the cutoffs. Understand this table only applies to those students who turn in five extra creditassignments. If you only turn in three extra credits, you get back 3% of the grading, etc.Dr. Laude’s new grade cutoffs (assuming you turn in all five extra credits.)Exemption scale (700 max) Cumulative scale (1000 max) Final Exam scale (300 max)LettergradeOld cutoff New cutoff(5 EC scores)Old cutoff New cutoff(5 EC scores)OldcutoffNew cutoff(5 EC scores)A 630 595 900 850 270 255B 800 750 240 225C 700 650 210 195D 600 550 180 1655. Didn’t turn in your first extra credits and wish you had? I will be extending the extra credit deadline for thefirst two extra credits for those of you who didn’t get them in. You now will have until April 24 at 11:59 pm toget your first three extra credit (EC 1 was teaching science to a science hater and EC 2 was explaining thethermodynamics of colligative properties.)6. Class schedule through the next few weeks. Note that because I let the material for electrochemistry slideforward, we will be doing the electrochemistry worksheet 9 in help sessions next week. CHEMICAL EQUILIBRIA20 H 4/7 Aqueous Equilibria Chapter 1821 T 4/12 Simple Equilibria: Solubility Chapter 20Worksheet 9:Electrochemistry22 H 4/14 Simple Equilibria: Acid/Base Chapter 18,1923 T 4/19 Simple Equilibria: Acid/Base Chapter 18,19Worksheet 10:Simple Water EquilibriaQuiz 5 Electrochemistry24 H 4/21 Simple Equilibria: Titrations Chapter 18,1925 T 4/26 Complex Equilibria: Acid/Base Chapter 18-20Worksheet 11:Complex Water Equilibria26 H 4/28 Complex Equilibria: Solubility Chapter 18-20 Quiz 6 Water Equilibria27 T 5/3 Review and EvaluationsH 5/5 Exam 3 (lectures 17-26)7. The worksheet for next week will be on electrochemistry. In the peer training sessions this week we will begoing over that sheet again. It will be useful to do that worksheet without the strain of exam 2 hanging over us,and working electrochemistry problems is the only way to really get to know the material.8. Coming to see me. As always I encourage students to come see me for help preparing for the final. As Ihave mentioned, last year over 100 students who were doing poorly in the course came to see me, and a hugenumber of those students went from getting Ds or Fs in the course to getting an A on the final. I have alreadymet with about 40 of you and encourage the rest of you to schedule a time by calling Judy at 471-6176. Iunderstand that my calendar can get clogged and it might not happen right away, but if you see me in the nextcouple of weeks, there is plenty of time to start preparing for and doing really well on the final.9. I’m big on doing. As I told my eldest last night, “son, there are those who do and those who don’t”. Ofcourse he ignored me, but that is his job. On the other hand, I am not your father so you can listen to me when Isay that your education here at UT will be mightily improved if you take the bold step of deciding to engage inan active learning environment. The best such environment, of course, is found in one of the hundreds andhundreds of research labs where people are curing cancer and figuring out how old the universe is. On Friday,April 15, from 11 till 3p.m. right outside this room, about 150 of your undergraduate peers in the College willbe displaying their efforts at scientific research. You should wander through and be amazed that people just likeyou are doing all kinds of science that you are just beginning to fathom right now. Use this as motivation to getstarted yourself—I believe it is the principle reason to go to a large university like UT—surely it isn’t themachine graded exams. For more information on the poster session: http://www.utexas.edu/cons/urp/postersession.php10. Extra credit number 3. Okay, so some of you remain unconvinced that you should spend time staring atposters about science that might make you feel inadequate compared to your peers. Well what if I offered up 10bonus points for coming to the poster session, finding a poster you like, talking to the person standing in frontof it for 5 minutes, and then going home and e-mailing me about your experience. Use the subject heading“interesting poster”, starting off with your name and UTEID, and then taking a few sentences to 1) tell me
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