In Sophomore organic chemistry there are lots of details that professors teach differently, but there will always be key fundamentals that everyone needs to know and understand. Some of these are always taught, but sometimes certain topics are skimmed over or skipped altogether. This is because your professor may think they are either too easy and you should just “get” how to do them, or on the other end of the spectrum your professor may be believe that the subject is too challenging and too many students wouldn’t understand regardless.
No matter the reason your teacher isn’t teaching you this stuff, you still need to get it! That’s right, I may be suggesting here that you learn something your instructor has told you “isn’t on the test.” But regardless of what teach says, you really should understand all of the following topics thoroughly by the end of first semester organic chemistry:
- How to draw Lewis structures and how to effortlessly convert back and forth between Lewis notation and skeletal drawings.
- Hybridization! What are the orbitals that make up a single, double and triple bond? How do p and s orbitals mix to give hybrid orbitals? How much s character is in an sp3, sp2 and sp hybrid orbital? How does this change kinetic reactivity, homolytic and heterolytic bond strength?
- Resonance! The concept as well as many specific examples. You should be drawing resonance structures for virtually any molecule in your sleep by the end of Orgo 1.
- Qualitative Bronsted acid base chemistry! You should know the following:
- Equilibrium favors formation of the weaker acid/base pair.
- How to identify conjugate acids and conjugate bases.
- Curvy arrows for an acid base reaction.
- This is the biggest part and it is very important: Make an effort to understand the important qualitative factors that govern the outcome of Bronsted acid base reactions: Resonance, induction, electronegativity, atomic size and hybrdization
- It would even be beneficial to memorize a few pKa’s, specifically those for simple hydrocarbons, acetic acid, Phenol, water, ammonia, the ammonium ion, the hydronium ion, hydrogen gas and ketones such as acetone.
- Know the common “strong” acids from general chemistry. Sulfuric acid, nitric acid, HBr, HCl and HI are all commonly used. Phosphoric acid is not quite a strong acid, but in organic it acts as one, essentially.
- Know and understand why unstablized carbanions (R3C: minus) are the strongest bases in organic chemistry, and be able to identify the other weaker, but still “strong” bases, Specifically RO minus (alkoxide and hydroxide anions), R2N minus (confusingly called “amides”) and H minus (hydride anions).
In the future I will possibly post some of my own tutorials as well as links to pages I’ve found helpful. Khan Academy has some videos on qualitative acid base chemistry that I think are fantastic.