Chem 201 Archive – Alan Shusterman

Category: Labs

  • Day 0, 2019 – the things you need to do BEFORE your first class

    Welcome back to Reed. We have an exciting organic chemistry curriculum planned for the 2019-20 editions of Chem 201 and 202, and we will get off to a flying start so here goes…

    Reed’s first week of classes is short because Monday is Labor Day. This means that two Chem 201 sessions, the Monday afternoon lecture and the Monday evening lab lecture, cannot meet. And because the course schedule ties the Monday and Tuesday lectures together, the Tuesday, Sept. 3, morning lecture is cancelled too. Our first days (Day 1) of lecture will be Wednesday, Sept. 4, and Thursday, Sept. 5. Your attendance at your scheduled lecture section on Day 1 is absolutely required.

    The Labor Day holiday does not impact the lab schedule. Our first (Week 1) lab sessions will meet Tuesday-Friday, Sept. 3-6. Check the schedule for your lab day (Tu/W sections meet 1:10-5 pm, Th/F sections meet 12:30-4:20 pm) and show up in Rm. 209 at the scheduled time or maybe a few minutes earlier.

    What will you be doing in lecture and lab? What do you need to do before class and lab so that you are prepared? These are excellent questions and the following instructions will guide you. Note: the following instructions have already been sent to all registered 201 students by email. Read, review, act as your situation requires.

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  • Models for Learning about Electrostatic Potential Maps

    The models you need can be downloaded here:

  • Ethanol IR models

    Click on the link to download a Spartan EDF2/6-31G** model of ethanol monomer and ethanol dimer. The models have been combined in a single file (a ‘list’ model) and they already contain calculated IR spectra, so do not replace them with SSPD models.

    Note: the IR frequencies in these models are unscaled and do not reproduce experimental values.

  • Lab Grades

    Nearly all of the lab reports have been graded so you can expect to see graded lab reports turning up in your inbox over the next week or so.

    The lab reports contain three grades: notebook, lab work, report. 99+% of the lab work grades were satisfactory, but this was not the case for notebook and report grades.

    Because unsatisfactory grades on notebooks/reports were fairly frequent, and because it is natural to assume the worst concerning such grades, I want to clear up any concerns that you might have about unsatisfactory marks.

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  • Preparing for EsCENTial Oil lab – weeks 2 & 3

    This lab experiment lasts 3 weeks. Students finished varying amounts of lab work during the first week so planning the remaining work is a little complicated. I’ve written up a two-page set of instructions to guide you. Please read this well ahead of your lab day and prepare accordingly.

  • How to interpret your IR spectrum

    There seems to be a little confusion about how to interpret your experimental IR spectra and how to use Spartan’s calculated spectrum. I hope the following will help clarify things a little (I recall that I had to interpret about 30-40 IR spectra as a student over a couple of years before this began to feel routine):

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  • Combination Coupling in Salicylic Acid 1H NMR

    The reading of Exp’t 4 (salicylic acid) lab reports informed me that many 201 students struggled with the complexities of the proton NMR spectrum. The NMR of salicylic acid is complicated, no doubt about it, but it can be understood and it provides a great introduction to the types of coupling patterns seen in organic compounds.

    Here are two readings that I strongly recommend:

    1. Combination Coupling Patterns in Salicylic Acid’s 1H NMR Spectrum (by me)
    2. Sorrell, “13.4 Spin Couplings in More Complex Systems” (p. 420)

    Sorrell’s treatment is excellent, but it might help to read my essay first because it explains a spectrum about which you have already thought a great deal.

  • Delete Peak = No-No in NMR

    An NMR spectrum provides important data on what’s in the NMR sample. Students are taught to look for certain contaminants – TMS, CHCl3, H2O – as a matter of routine. As many know, however, removing the last traces of chromatography solvent, unreacted starting material, and so on, can be a difficult chore so some Japanese science students have apparently hit on an elegant solution: using the ‘Delete Peak’ option in the JEOL NMR software to remove unwanted peaks. Needless to say, the editors of the journals that had published these spectra, and the students’ research mentors (once they were informed about the spectra) were not amused (“Cleaning up the record,” C&ENews, April 21, 2014, p. 32-3).

    ‘Silent’ alteration of data (by ‘silent’ I mean that the alteration was not reported to a referee or a reader), even if it involves removing ‘unimportant’ peaks, or peaks due to impurities, is nothing less than scientific fraud. If you have questions about how to process your data, or what data and data processing procedures to report, always bring your questions to your research supervisor, the journal editor, and colleagues in the field. Scientists, and more often, science students, tend to keep such questions to themselves because they think they will lose their colleagues’ respect by asking a “stupid question.” In fact, the sure-fire way to lose this respect is to engage in fraudulent practices.

  • NMR & IR slides from lab lecture

    A few of you were unable to attend last night’s lab lecture. Here are slides from the lab lecture (bonus prize: GC data for a ‘standard’ mixture of isopentyl alcohol and isopentyl acetate):

  • Oct 10 lab lecture slides – distillation

    You can download a copy of tonight’s lecture here.