Survival Kit for Premeds: Organic Chemistry Lab

Photo Credit: Copyright 2013 Coral von Zumwalt

While organic chemistry class itself is daunting on its own, the lab portion is flat-out terrifying. It requires knowledge from organic chemistry as well as general chemistry, which most people in the class took at least a year ago. I heard how difficult the class is and I kind of tried to prepare for it by reviewing some old chemistry material, but I felt overwhelmed with the amount of information and didn’t really know what to focus on. So this is my attempt to give you guys an advice on how to endure through one of the toughest lower-division science courses here at UCLA. I specifically took the CHEM 30BL course last quarter, and I will be basing my advice on that class.

1. Reviewing general chemistry concepts

The class requires you to know some key concepts from general chemistry that is readily used in the laboratory. By knowing some general concepts, you can better understand what is going on and learn how to make adjustments to reactions when things don’t turn out as expected. Some of the key concepts you should know are solubility (what determines whether compounds are soluble in water or organic solvent?), polarity (what makes a compound polar?), acid-base chemistry (Arrhenius and Bronsted-Lowery; what does it mean for a molecule to be acidic/basic?), and equilibrium constant (calculations involving molarities of products and reactants; pKa values/meaning). Polarity seems to be the hardest for people to really understand, and it was definitely the hardest for me on the final. Knowing these concepts inside-and-out will greatly benefit you throughout the quarter.

2. Organic chemistry knowledge

While the lab obviously does not cover all reactions learned in organic chemistry classes, it does cover some of the most simple reactions. The reactions themselves are not what makes the class so challenging. So do not stress over having to know all of the mechanisms for the reactions. But the reactions that my class covered were acid-catalyzed dehydration, phase transfer catalysis, various oxidation reactions, Diels-Alder, Grignards, and Fischer esterification. What is most important while doing the experiments is that you understand the reasoning and logic behind each step of the experiment. Why are you using that particular solvent? What will the sodium carbohydrate do to the crude product mixture? Which layer is the organic layer? Why do we reflux the mixture? What does this color change indicate?

For data analysis, you will need to know how to interpret basic IR, H-NMR, C-NMR, UV-Vis Spec, and polarimetry. Also, make sure to review and understand how TLC (thin-layer chromatography) works. Understand what determines the Rf value (retardation factor). This will be covered in lab as well as in the final.

3. Prepping for final

The score breakdown for my particular class (CHEM 30BL) consisted of weekly online quizzes, in-lab quizzes, pre/post lab reports, in-lab assignments (not every week), lab notebook, and a final. So there is no midterm and the only test you get is the final. Start studying for the final EARLY and you’ll be glad you did by the time finals week rolls around. I recommend getting started in week 5 or 6, so that you’ll have time to go through the practice tests as each test takes a pretty long time to go through. For 30BL, you are provided with a booklet of past finals. Use it! Know it inside-and-out. If you don’t understand something, visit his office hours! The instructor is very generous about giving up his time and has office hours everyday. Go in there and befriend him. He’ll help you out.
As for what to study for the final, I would focus mainly on the reader and the practice tests. Make sure you know all of the experiments that were done in the lab (including the questions listed in the back of each experiment!), and go through all of the practice tests and try to understand the reasoning and general concepts. The final consists of a experiment/mechanism section, TLC section, polarity section, lab technique section, IR spectra, and structure identification (given: molecular formula, IR, H-NMR, C-NMR/dept).

Overall, just stay on top of the material. Read over the experiment thoroughly before attending lab, visit office hours often, and study hard throughout the quarter. It may be intimidating at first to visit his office hours, but I swear he’s a nice guy! He makes an effort to learn the names of people who show up during office hours, and he calls you by your name by like the third time you come in!

It is definitely a challenging course, but hopefully you will come out of the class saturated with applicable chemistry knowledge.

Good luck! And contact me if you have any questions.