Archive for the ‘Coursework’ Category

Organic Chemistry Exam Show-and-Tell

Wednesday, November 13th, 2013

ChemBark's Orgo BunnyWhen I was in college, there was a professor who was notorious among the grad students for stopping them to show off his organic chemistry exam questions. Unlucky TAs on their way to the bog would get tied up for what seemed like hours going through drafts of exams in the hallway.

But now I think I know how he felt. There’s a certain degree of satisfaction associated with writing a problem that makes students integrate their knowledge of multiple subjects within a given set of consecutive chapters in whatever textbook you’re using.

Instead of stopping TAs in the hallway at work, I figured I could move the practice into the 21st century by using the blog. I’ll post any gems I’m proud of in this thread. Feel free to share your favorites as well.

To start…

Exam 1, Problem 3-2. (8 points) Draw the most (Brønsted–Lowry) acidic, optically-active isomer of C6H10.

Click here for the answer. The chapters for this exam included acids and bases, isomerism, functional groups, alkanes, and stereochemistry.

BRSM is Coming to America

Tuesday, May 28th, 2013

There’s a chemblog carnival afoot to wish BRSM well on his upcoming postdoc in the U.S. @JessTheChemist is curating the posts on her blog, here. You can check out more info on Twitter with the hashtag #BRSMBlogParty.

BRSM is a synthetic organic chemist with a great blog dedicated to the subject. I know little else about BRSM beyond that he/she is currently based in the UK. (Obviously, I’m not even 100% sure about his/her gender.) That makes answering some of the carnival questions harder, but I’ll give it a shot anyway:

1. What is your message for BRSM?

Best wishes for your upcoming postdoc in the US, wherever it may be and in whatever area of research.

2. What is one postdoc survival tip you would give to BRSM?

Try to be nice to—or at least respectful of—your colleagues. Be especially nice to people like janitors, security guards, secretaries, instrument staff, and administrators. There will be times where you’ll need their help getting out of a bind, and having any of these people as enemies can make your life hell.

3. Do you have a fun story you could share from your postdoc and/or US academic experience?

Well, there was the kitty job interview. There was also the time we (unknowingly) named our high-school science outreach program after a sexual act. Oops.

4. A survival tip for living in the US?

Relative to what you have in the UK, our public transportation is poor. If you are going to live in or near New York City, Boston, or San Francisco, you probably do not want a car—parking stinks. If you are going to live somewhere else, you probably do want a car.

5. What would you like to see on BRSM blog in the future?

Tasteful nude photos.

No, seriously, whatever you want. I would rather you keep blogging about what interests you than burn out blogging about what interests other people. And thanks for posting the Felkin-Ahn slides; I think they make a nice companion to Dave Evans’ Chem 206 notes.

6. Anything else?

Nope. Safe travels!

Jean-Luc Picard Failed Orgo

Monday, April 29th, 2013

Yes, you read that title correctly: Jean-Luc Picard, the greatest starship captain of all-time, failed organic chemistry at Starfleet Academy. In his defense, it was probably less to do with intelligence and more to do with being distracted:

I pulled that video clip so I can show it to my students during our opening lecture. It should go well with the “How to Win Orgo” handout.

Update (5/1): Thanks to a tip in the comments from “bad wolf”, I went and pulled a clip from Star Trek: Generations where it is revealed that one of Picard’s ancestors won the Nobel Prize in Chemistry. It makes his failure in orgo all the more astonishing.

WWWTP? – Markovnikov Edition

Tuesday, April 16th, 2013

Perfectionists take note: even titans of catalysis make embarrassing mistakes with their chemistry. Just look at this little oopsie that was caught by an astute reader in the Midwest.

It seems like there might be a bit of confusion hanging over the chemists developing methods for anti-Markovnikov hydroamination of alkenes at the Center for Enabling New Technologies Through Catalysis (CENTC):

centc_markovnikov_error

Ummm….yeah….that’s not the difference between Markovnikov and anti-Markovnikov addition.

Those of you who’ve taken sophomore organic chemistry will remember that Markovnikov’s rule states that protic functional groups (e.g., H-NR’R’) will typically add to double bonds such that the hydrogen adds to the less substituted carbon (and the other group, e.g., -NR’R’, adds to the more substituted carbon.) What Hartwig and coworkers have drawn as the Markovnikov product is still anti-Markovnikov. The products they’ve drawn might charitably be called conformational isomers, but they’ve failed to note any 3-D structure.

Of course, the true Markovnikov product would place the amine on the same carbon as the R group.

WWWTP? – Nomenclature Edition

Sunday, June 24th, 2012

There is nothing like a trip to my mailbox to bring a nice little blogging hiatus to a crashing halt. While attacking my pile of C&ENs, I caught this ad for TOSOH Organic Chemical Company on page 43 of the 11 June 2012 edition:

I guess the hair net and painter’s mask ensure that—unlike my Orange Chicken at Panda Express—these products arrive free of human hair. Matters of lab attire aside, what actually piqued my interest in the ad were the compounds for sale:

Sigh. That is not how I was taught to name organic compounds. My orgo professor—on the recommendation of IUPAC—told us to start by numbering the longest chain of carbons. Thus, 1-bromo-2-ethylbutane is properly named 3-(bromomethyl)pentane, and 1-bromo-2-ethylhexane should be 3-(bromomethyl)heptane.

Avid readers of ChemBark know that I love trick questions, and structures like the ones above make for great nomenclature practice. Many students will instinctively assume the carbon chain extending from left to right is the longest. When I taught orgo, I had to purchase red pens by the dozen.