There’s a lab class that most chem majors at Caltech have to take: Ch4. Nicknames include CH4ever–this is the most popular–and, more recently, Ch4rrible. That’s my favorite, because it’s a little ironic. I do like the class quite a lot, but it can be a lot of work.

It’s not called Ch4ever for nothing. The prelabs take several hours and are required to be extremely thorough. Not only do we need to copy the procedure completely, we also need to make a table of chemicals we use and basic information like molar mass, melting point, and density, as well as amounts we use in lab units and moles.

In Ch4, we do a lot of spectroscopy to characterize our products, so we need to make predictions for every test we’re going to take that week in the prelab.So far we’ve learned out to do infrared spectroscopy (IR) in three different ways (a potassium bromide pellet containing our sample, a salt plate containing our sample, and everyone’s favorite, the diamond-tip ATR, which simply involves scooping a small amount of sample onto the platform and taking the spectrum).We also became quite familiar with nuclear magnetic resonance spectroscopy (NMR), gas chromatophy mass spectroscopy (GCMS), and melting point tests.

Ch4 is nicer than Ch3, the intro chem lab that all Caltech undergrads are required to take, in that we have more freedom in choosing what glassware we want to use. Instead of being allotted a set number of each type of glassware, we’re free to roam around the lab and pop through all of the drawers, taking whatever we please (and whatever works). Erlenmeyer flask or round-bottom flask? Measuring pipette or graduated cylinder (don’t forget the funnel if you don’t want to spill)? Everything is cleaned between lab periods with solvents and arrives sparkling new by the next lab section.All this freedom is designed to help us develop our own style and intuition of working in a lab.

Since most of us are sophomores or older, and have SURFed the summer of our freshman year, we’ve gained a bit more lab intuition since Ch3 and are able to do better experiments. There’s also pretty cool equipment besides all of the spectrometry stuff, such as a rotary evaporator (attach your flask and it evaporates off your solvent for you), a vacuum filter, and a flash chromatography column.

Synthesizing three derivatives of triphenylmethanol on steam bath and hot plate.

Colored crystalline compounds. Note that organic compounds are usually white crystals, however.

We go in twice a week for three hours at a time. The sections are smaller than Ch3, maybe 12 people or so, and we get a lot of one-on-one TA and instructor attention. I may have accidentally set my instructor on fire once during lab (we were extracting a highly flammable reducing agent via syringe under a cold nitrogen atmosphere) but I am definitely learning to be a better chemist.

Till next time,