No doubt you’ve got some important exams coming up. With that in mind, here’s three simple tactics you can use during exams.
1. Draw partial charges
If you get complete brain-lock during a question, try drawing out the partial charges. Ask yourself what the most electronegative atoms in the molecule are.
The most electronegative atoms (e.g. oxygen, nitrogen, chlorine) are generally going to have partial negative charges on them, while carbons that they’re bonded to will have partial positive charges. This will help in identifying potential nucleophiles and electrophiles. And since opposite charges attract, this can help you figure out where the any reactions might occur – a handy thing to know when you’re stuck.
2. Draw in hidden hydrogens and lone pairs.
Remember that we often – for reasons of laziness – won’t draw in the “hidden” hydrogens and lone pairs that are present on atoms. If a problem is giving you a hard time, draw them in. This especially goes for mechanism questions and synthesis questions, since you’ll really want to be able to see everything that’s going on. Sometimes just a little clue like you’ve lost (or gained) a hydrogen on a certain atom can be the crucial piece of information that moves you forward.
3. Number your carbons.
It’s hard enough to understand what reaction you’re looking at and how it might work. What really hurts is getting the answer right, but losing grades because you skipped drawing in an atom or two. If you number your carbons, you’ll greatly decrease the chances of making simple mistakes like this. Even after all these years, I still make little mistakes. The difference is that I know how easy they are to make that I’m 10 times more paranoid about making them than normal people are.
The other nice thing about this technique is that it’s a little brainless. You can do it – and it’s useful – while actively thinking about how to do the problem.
What are some of your best organic chemistry study tips? Share them in the comments below!
James
One of mine is that if the exam format is changed up for any reason (personal example: your final is multiple-choice but you’ve been taking free-response midterms all semester), take a practice exam in the new style prior to the exam, so you feel confident when you walk in and don’t freeze up.
Another is to bring your model kit, if it’s allowed. Even if you think you won’t use it, you never know. There could be a tricky stereochemistry problem and then the model kits become life savers.
A classmate of mine suggested a third, though you may need to ask your proctor beforehand: If you know you can’t write on the exam, plan ahead what you will do to keep track of your work. She brings in write-on transparencies with markers and white-board erasers so that she can write over the top of the exam and not make silly mistakes in transferring the problem to a separate sheet of paper.
Great tips Heather – thanks! I’d never thought of bringing transparencies before!