Chem 201 Archive – Alan Shusterman

Category: Homework

  • 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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  • Where do I put my CH3 groups in a condensed formula?

    I’ve been getting a lot of office visits and emails over the same homework problem. Folks say, “I typed CH3CH2CH(CH3)CH(CH3)CH3” or “I typed CH3(CH3)CHCH…” or “I typed CH3CH(CH3)CH…” and it was marked incorrect. =(

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  • Challenge/Conference Problems or HW/Book Problems

    I have (and will) post some extra “challenge” problems from time to time. Let me explain their purpose so that you can work these problems into your schedule in an appropriate way.

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  • Fall Break fun: complete Sapling survey, win prizes

    Sapling sent this announcement to me today:

    Sapling Learning is committed to providing the most effective online homework and the best support in higher education. We need feedback from you and your students to make sure that we are aware of where we can improve. As a token of appreciation for your time and feedback, each instructor who completes the survey will receive a $5 Starbucks gift card. As an incentive for students, we will be giving away an Apple iPad mini to 3 students randomly selected from those who complete the survey. The student survey must be completed and submitted by November 8, 2013 to be entered to win. Student winners will be announced on November 15, 2013.

    Please share this link with your students: https://www.surveymonkey.com/s/studentfall2013

    We thank you and your students in advance for taking 10 minutes to complete our survey.

  • Challenge Problems + Molecular Modeling Questions = Answers

    I promised that I would post answers to the challenge problems in the learning activities and I have also received requests for 'answers' to the molecular modeling activity (#2). Here are some answers and comments.

    Keep in mind: many of the questions in the learning activities are designed to help you build concepts. They are not "problems" in the usual sense and they don't reflect the kinds of problems that might appear on exams. Your book's end-of-chapter problems offer a much better idea of what you can expect exam-wise.

    Learning Activity #3 – Answers to Selected Questions & Challenge Problems

    Learning Activity #4 – Answers to Selected Questions & Challenge Problems

    Molecular Modeling #2 – Answers to Selected Questions

  • Hg-free Exams? Not quite

    Homework assignment #6 contained an important announcement, but many students who worked on the homework either ignored the announcement or didn’t fully understand it (and many students may not have even seen the announcement given the small number of completed assignments that were turned in).

    Here’s the announcement quoted in its entirety and verbatim:

    Reagent Alert: I will not cover, and I am not going to test you on, the chemistry of Hg(OAc)2 + H2O, then NaBH4, but Loudon uses this reagent extensively in practice problems. Every time you run into this reagent, simply substitute another reagent in its place: H2O + cat. H2SO4.

    And here’s what I saw on HW #6:

    • occasionally replacement of the entire oxymercuration-reduction reagent with H2O + cat. H2SO4 (correct behavior)
    • more often, replacement of parts of the oxymercuration-reduction reagent with H2O + cat. H2SO4. This is incorrect. Do not draw hybrid reagents like “H2O + cat. H2SO4 then NaBH4”. In fact, do not resort to oxymercuration-reduction in this class at all.

    But that’s not all. This reagent-alert does not mean that you should never draw Hg-containing reagents. The activity for class #33 – Alkyne addition reactions: hydrohalogenation and hydration describes the use of salts containing Hg+2 as a method for promoting hydration of alkynes.

    Bottom-line: draw H2O + cat. H2SO4 to hydrate alkenes (Markovnikov) and draw H2O + Hg+2 + H2SO4 to hydrate alkynes (Markovnikov).

  • Advice on working with models

    Problem-solving
    and working with molecular models are fundamentally different activities. It’s
    natural to feel some urgency when you practice solving problems, and the more
    you practice solving a certain kind of problem, the easier and faster it should
    get.

    This is not a useful way to approach the molecular modeling questions on homework assignments. The models that
    you build contain a lot of information, some of it useful, some of it
    not. You should take your time to
    look the models over from different angles, juxtapose what you see against what you have learned
    elsewhere, and develop some mental pictures that inform your understanding of
    chemical phenomena. The goal is not to learn a new problem-solving skill, but to create another dimension for thinking about chemistry. If you don’t feel like you have the time to do this, save
    the models for another day.

  • Last Semester's Paperwork

    I spent a good chunk of winter break buried in paperwork. The stack of final exams, lab reports, and late homework assignments was almost 10 inches thick, but I eventually got through it.

    Now I want it to go away, all of it. Well, not just go away (I could have dumped it in the recycling if I just wanted to make it go away), but actually get it back into your hands where it might do some good.

    Please stop by Kathy Kennedy’s office, room 303, and collect your papers before next Friday, January 29. Thanks.

  • The Paper Trail

    I will try to keep you up-to-date by email, but here is where things stand:

    HW #1-7 – everything that I have ever received has been read and returned. If you don’t have your assignment, check the box outside my door. If it isn’t there …

    HW #8 – I am currently reading these and adding them to the papers outside my door. I expect to finish them before I leave work today, but I can’t promise that.

    Exam #1-3 – everything that I have ever received has been graded and returned. If you don’t have your exam, check with Kathy Kennedy, Rm. 303.

    Lab reports – I have returned all lab reports except for the isopentyl acetate (banana oil) and acetylferrocene. I will begin returning some of the isopentyl acetate reports today and that will continue through the weekend. I hope to have them all read by Sunday afternoon, but we will see … You will not be allowed to revise either the isopentyl acetate or acetylferrocene reports. What’s done is done.

  • Exam #3 results

    I posted answer keys for Homework #7 and for Exam #3 over
    the weekend. I have also finished grading Exam #3 and I tried to hand back as
    many exams as I could during class today. If you didn't receive your exam, stop by
    Kathy Kennedy's office (Rm. 303) to pick it up. I am still reading homework assignments (and
    lab reports) so more paper will come your way on Wednesday. (more…)