wtf is this, why do we have to derive the formula for the probability of a molecule having a certain speed in the second chem class here? its harder calculus than 31A/B

TL;DR: He is not excellent, but definitely not that bad. 7/10.
My friends and I agreed that he is a sociopath, but that's not necessarily a bad thing. If you are fine with a professor with "I don't care" written on his face, you will find him a fairly good lecturer. His class is really engaging and as opposed to what most comments say, he never makes fun of the students' mistakes. He does not require a textbook because he writes a 500-page-long class note and keeps updating it.
The first two weeks are difficult but after that, it's mostly AP chemistry content. The homework is constantly hard, but if you frequently visit your TA (thank you Rupert!), you can get most points out of it. Even if you don't, the homework does not take many points anyway.
His exams are much easier than the homework and practice problems from discussion sessions and they are curved. There's no reason to blame the exam as hard since the average for homework is over 90% of the total.
And I think he looks like Eminem, which my friends don't agree.

The average for the first midterm was a 38%... enough said

Prof Bouchard is misunderstood by the student, I'd suppose. Even though the course materials are hard, Bouchard gives fairly clear lecture about these course materials. His lecture notes posted online are very thorough. The test is very hard, but if you work through lecture notes and the problem sets posted, you will be fine. Also, prof Bouchard is really helpful and really willing to help students during his office hours, and especially outside OH. He would simply tell you to just come by his office, and he will help you with your problems. Good professor overall. But if you simply don't like Chem 20B materials, you can find other easier professors.

The past reviews of Bouchard are no longer valid. He’s not the greatest professor, but he’s much much better than previous reviews would have you believe. I wanted to avoid his class at all costs when looking at reviews, but was surprised when he was actually a pretty good lecturer, his grading and tests were much friendlier than reviews would lead you to believe and the work load wasn’t too crazy. I don’t know what the other professors are like, but if you end up taking Bouchard it’s not bad.

Based on previous reviews, I strongly believe that Professor Bouchard changed his teaching style/class format between 2017 and 2018. Various aspects of the class that are brought up in previous reviews were simply not present when I took this course (Winter 2019).

Teaching general chemistry/physics/etc. courses is substantially different from teaching upper-division coursework, and while I wouldn't necessarily say that professors are "justified" in being somewhat harsher in the first case, I have encountered this myself several times. Bouchard is an exception to this; his passion for chemistry is immediately evident from the first lecture, and he is eager to impart this knowledge to his students through multiple avenues.

Bouchard has a gift for explaining not only the fundamental principles of chemistry, but also their mathematical basis; the textbook for this course consisted entirely of his own lecture notes, compiled over several years and edited by certain students. This was, if anything, substantially clearer than the "official" Oxtoby textbook, inasmuch as he took the time to meticulously derive every formula/equation/law used in the topics that we covered.

I regularly attended his office hours during the course whenever I was able; although only a few students did so, it was well worth it, as it became surprisingly easy to have multi-hour chats about science/mathematics/life in general. I learned several concepts there that I was then able to apply in further courses, making these opportunities of great use to me.

Bouchard is committed to the success of his students, and will take every opportunity to clarify/explain any concept that is requested. He does so in a way which encourages questions, rather than discouraging them as certain other professors do; this is extremely conducive to generating a healthy learning environment, in my opinion.

Overall, I would very much recommend Professor Bouchard for this course; while it is certainly more in-depth than other professors, it is well worth the extra effort due to its immense payoff in future courses.

Bouchard treats his Chem 20B lecture the same as Chem 20BH. Every single lecture is filled with incomprehensible derivations of the most complicated equations. And he expects you to remember how to do these page long derivations. The only way to solve his homework problems are to guess randomly for the multiple choice and spend hours doing each of the numerical responses. I have never had a class where I felt so stupid and frustrated trying to get through the homework. His tests are very challenging and thus curved heavily. I wish I could say that I learned a ton from his class but honestly I didn't do anything except meaningless derivations. Bouchard is a pretty nice guy and clearly a genius but his teaching style makes this class an absolute NO. Pick any other teacher and save yourself from this hell.

The only class I've had that's miserable enough to warrant a review, and Bouchard just makes it worse.

He’s the greatest Professor I’ve taken in UCLA ever. I don’t understand why someone’s saying that he requires us to read the textbook—

This man single-handedly ruined my GPA.