Chem 201 Archive – Alan Shusterman

Month: August 2012

  • Learning Activity #2 – Corrections

    Some corrections and clarifications for Learning Activity #2 follow. Let me know if you have other suggestions.

    • #DU. A ring and a double-bond both count as 1 DU. Consider some three-carbon compounds. CH3CH2CH3 is propane, the saturated molecule. CH2=CHCH3 is C3H6. This molecule is one H2 short of saturation (1 DU). Cyclopropane, (CH2)3, contains only single bonds in a three-atom ring. Because its molecular formula is C3H6, it is also one H2 short of saturation (1 DU).
    • Model 4. The definition of alkane might be reworded to make it clearer. Let's try alkane = saturated hydrocarbon.
    • Fact 2.3 gives an incomplete definition of branched alkane. A branched alkane must contain at least one methine (CH) group OR one quaternary C.
    • The right-hand structure in Fig. 2.5 is incorrect. Add another CH3 group to the left end of the molecule so that there are 8 C's in the chain.
    • Re-word Q#19 to read, "Circle each group of C in Fig. 2.5 …". The idea is to draw a single circle around each alkyl substituent.
    • Q#20-22 might lead to some confusion (Sorrell will straighten you out). An alkane is a molecule in which all of the C and H bonding patterns are obeyed. An alkyl group contains one C with only three bonds, a rule violation. Thus, methyl is derived from methane. Q#20-21: the suffix that methyl and ethyl share is 'yl', not 'ethyl'. Applying this in Q#22 leads to CH3CH2CH2 = propyl and so on.

    Friday, Aug 31 update. Several students called my attention to an apparent contradiction in Model 6 and Fig. 2.6. The molecule on the left is named 2-ethyl-1,4-dimethylcyclohexane. This name appears to contradict the rule given in Model 6 that states, "C#1 is the ring carbon bonded to the substituent that comes first in the alphabet (prefixes like “di” and “sec-” are ignored)". The rule suggests 'ethyl' is located at C#1, but the name that was provided clearly assigns a methyl to C#1.

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  • William Perkin? Meet Silas Cook!

    Organic chemistry has a long history. This week we took a look at William Perkin, whose "unsuccessful" preparation of quinine spawned an entire industry, and Silas Cook, Reed '99, who recently supervised the first short "total" synthesis of artemisinin.

    A closer look at the following web pages reveals that I reported some dates incorrectly in class: Queen Victoria wore a mauve-colored dress, but not until after the Royal Exhibition of 1851 was just a memory.

    A nice book on the subject of Perkin, mauve, etc., is Mauve: How One Man Invented a Color that Changed the World. You can also learn quite a bit at these links:

    • William Perkin, 1838-1907. The teenager who "dyed" Queen Victoria purple
    • August Wilhelm von Hofmann, 1818-1892. The professor who took on a precocious 15-year-old assistant. Wikipedia also describes him as the first lecturer to make use of molecular models
    • Quinine, an early treatment for malaria obtained from the cinchona tree
    • Artemisinin, a "new" treatment for malaria obtained from sweet wormwood
    • Mauveine, the dye that transformed commoners into royalty
    • Silas Cook (Reed '99), Chemistry Department, U. Indiana. His Reed thesis title was: "The synthesis of 3,5-bis(carboranyloxy)benzaldehyde : the precursor to a novel boronated porphyrin for use in boron neutron-capture therapy"

  • MUST READ: O-Chem Week #1

    Hi, This is Alan Shusterman, your Chem 201 instructor.

    Classes get underway tomorrow and the first o-chem lecture will be in Eliot 314, but o-chem will actually start earlier in the day for some of you. Confusing? Let me tell you exactly what you need to know.

    Lecture this week. There are two lecture sections for Chem 201 this year: MW 3:10-4:30 & TuTh 10:30-11:50. Both meet in E314. The caps have been lifted a bit in order to make room for 82 students (45 in MW F01 and 37 in TuTh F02). Please attend only the section that you have registered for. If you are still trying to add this class, you must come see me and persuade me to sign an ADD form because online registration is closed.

    CLICKERS this week. I plan to use clickers starting on Day 1. Bring your clicker to every lecture. If your clicker needs to a little tender care or a juicier battery, take it to the Bookstore on Monday morning. If you can't find your clicker, you can buy one at the Bookstore.

    >>> LAB THIS WEEK <<< Labs will meet every day this week, starting tomorrow. We have four lab sections for Chem 201 this year: MTuF 1:10-5:00 and Th 12:30-4:20. Lab lecture takes place in Psych 105 for all students on F, 9-9:50. Please attend only the section that the Registrar has placed you in. (Note: the Registrar reassigned several students to new lab sections last Friday nite so your schedule may have changed.) If you were on a waiting list or if you would like to change lab sections, you will need to come see me and persuade me to sign an ADD form. If you absolutely cannot make it to your assigned lab section, then please come to the section that you would like to be in. Here's our tentative lab schedule for this week:

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