Okay... so I'm sure you've already seen a lot of the other reviews... BUT I'll say that most, if not all of those were written before the final exam. Going by what the final looked like, it seems that he's starting to improve based on this criticism so that makes be hopeful for future classes. It kinda hurt to see all these negative things being said about him because he really does seem like a genuinely nice person. As a teacher though, I'd say a fair amount of that criticism is warranted. But of course, this was his very first class ever, and we can't expect him to be perfect right off the bat.

Look, I didn't really have a good time in this class, I'll be honest. But I also don't think getting a class with Barr is a death sentence. He can only improve from here, so I sure hope whoever's reading this in the future will have a better time than I did.

Professor Barr's greatest weakness is his inability to understand that his students are humans.

To me, Barr was much better than I thought he would be. He was generally an understanding guy and gave lots of extra credit on exams -- which honestly weren't that bad in themselves. I was terrified by reviews from his previous class (which was during COVID) citing impossibly difficult exams --- and they were definitely right as we were given a past midterm for practice and all I'll say is I'm so glad I didn't choose to take it then. But since we were in person this quarter and exams weren't open note (we did get a cheat sheet every time though), it seems like Barr adjusted his exams to be easier to reflect that. I did not do any extra studying outside of class other than the day before each exam; I did not do his problem sets, and did not read even one word of the textbook. What I do recommend is going through his learning objectives list and going to his office hours -- especially the ones right before the exams -- because he would often give really important information that will be on the exam that he NEVER mentioned before in class. Another annoying thing about the class is that there are so many random assignments due on random days and as someone who is disorganized it's impossible to not miss one or two. So yeah. Good luck y'all!

tbh his class is hard af but u sure do learn a lot… im a chem major and this class has been making me consider other majors :) if you don’t have a choice and end up taking Barr u seriously need to have an open schedule because office hours is the only time where you can ever get answers to anything and they’re basically extensions of the lectures cuz some of the info covered there is so important. Don’t take this class with a heavy schedule because it will take up the majority of your time. He refuses to curve and the final we just took was god awful. His exams are extremely difficult just like his problem sets are (except without the internet or ur notes) good luck lmfao and do the problem sets and go to office hours and prepare to sacrifice a lot

:(

If there is any other option, take the other option. If you can delay taking this class until another professor besides Barr offers it, do that. If there is another professor, take the class with that other professor. If you're thinking of switching to a different major, and that major just so happens to not require taking Chem20B, this is your sign to switch your major. Please. For your own sake.

The tests are so much more difficult than what he actually prepares you for. Even with excessive amounts of self-teaching and absolute devotion to studying for the tests, the tests kicked my ass. He is a really nice person, he tries so hard to be a good professor, and he really puts in an effort for the class, but he just doesn't give tests that are reasonable for what you learn.

Do not take this class with Barr if you can avoid it. Unfortunately, he was the only 20B professor this quarter, meaning I was stuck with him. I thought that my knowledge from AP chem would be enough for me to get through this class rather easily, and up until the first midterm, his lectures reflected that belief. His lectures make the material seem pretty reasonable; however, his "optional" problem sets (that he doesn't provide answer keys for) and his exams display how surface level the topics covered in his lectures are. He covers the bare minimum during lectures, but then tests you on a much deeper and confusing level. His lectures are also very chaotic, start five to ten minutes late, and are extremely rushed.
The first midterm was pretty confusing, but it was nothing compared to the second midterm (class average was around 60). Barr's exam questions don't test you on your mastery of the topics; they test you on how well you can decipher his bullshit in order to figure out what he is actually saying. His questions are long-winded, convoluted, usually are on things never covered during class, and are only vaguely connected to class material.
Barr also likes to pride himself on having his students interact with him, the TAs, and other students. None of this interaction is voluntary. His homework assignments, two of which are due right before exams, are completed in groups assigned by the TAs, and are significantly easier than any test question, making them time-consuming busy-work. Barr "encourages" his students to do the problem sets and come to his office hours, but it is clear that these things are necessary in order to do well in his class.
In the beginning of the course, he says that he goes over problem sets in his office hours instead of providing answer keys. I only attended a few office hours, but during this time, he rarely completed a full problem set, leaving the other questions unanswered and was unwilling to provide the answers.
Ultimately, this class is too much work and purposely made more difficult by the exams. Barr seems like a really nice person, but is an unorganized and stress-inducing teacher.

Worst Professor ever! In this class you don't need to spend any time on review sessions cuz the exams are just unrelated to the lecture at all. This professor is trolling. Avoid him at all cost even though it seems Chem20B is only taught by this guy.

DISNEY ADULT!!! That right there should say enough but for real I haven't met a single person in this class who likes him. He won't give out answer keys to the practice problems (even the ungraded ones which makes no sense) so in order to get answers for anything which is crucial, you have to sit through hours worth of office hours each week, which is so inconvenient. In addition, he uses exams as an opportunity to try and trick students and test out new things that we have never learned that are so loosely related to the actual topic. Overall, do not take him if you do not absolutely have to.