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.

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.

Barr's class was very strange. He seems like a really nice guy, and it was his first quarter, so I'm pretty confident he'll be a better instructor in future terms. I think he really wants us to love chemistry. His homework problems are very in-depth, his midterms were extremely nuanced and difficult, and his class is structured such that students in office hours have a huge advantage. I didn't really want to commit this much time to chem every week, especially after being told 20B would be easier than 20A and more like AP chem. I was pretty unprepared for the level of material in this class, and I consistently felt like I was lacking a basic understanding of the material, which I needed to succeed. Barr's midterms were insanely difficult. I probably studied 20 hours for them (which is much more than I usually study) and barely passed one of them and didn't pass the other. Barr confidently doesn't curve, and this is pretty frustrating when it seems like at least half the class is failing. But somehow the final helped us all get good grades?? My guess is he ended up curving because I would've had to get like an 86 on the final for an A and I managed one even though my final grade was a 70-something. The final was very reasonable. It reflected the lecture material and was relatively straight-forward. I was very impressed with the lack of trick-questions as opposed to the midterms. However, this does not mean this test was easy. I studied the most I've every studied for tests in this class, which was a bit annoying because of how little the tests reflected the basic understanding of concepts required for the class. Then, there was the homework. There were problem sets every week, which you absolutely cannot do without going to office hours and watching him explain the questions. They're very very difficult, but reflect the midterm difficulty, so to succeed you HAVE TO go to office hours. You really can't get by without it, and the people I know who got As are basically the people who went to office hours. The homework is assigned four times on Friday evenings and due Monday mornings. You have to work in a group (even online), which are assigned in week 2 of discussion. These were really inconvenient if you had different time zones or work shifts and were trying to coordinate over zoom every other weekend. My group was really good though. We're all good friends, so we didn't mind it too much and it helped us succeed. But if you didn't like your group or couldn't make office hours you're kinda fucked. Overall, you'll survive. Do your best on the midterms (16% each), do all the OWLs and surveys and participate in discussion (total 20%), and get >80% on all the homework (will give you full credit, category worth 18%). Then all you have to do is study your ass off for the final (30%), and if you manage to pass it, you'll be guaranteed at least a B. Good luck!

I don't even know where to begin with Professor Barr. At first, I thought he would be a decent Professor, but as time went on that hope vanished overtime before being shattered by the second midterm of his. Thinking further on it, there are three main issues that need to be fixed in this class.

The first encompasses his exams. While there were no problems with the first midterm, the second midterm and final had glaring issues. When I took them, the questions were worded very poorly, and it was hard to determine what I was meant to do. Moreover, the Professor does not answer questions during his exams despite repeatedly saying he would. I recognize that the large class makes it difficult, but it's simply unacceptable to expect students to determine the thought process that he was seeking. Moreover, the Professor conducts a period before each exam where he goes through the questions and "explains" what he's seeking. This period is more than useless and is actively dangerous to listen to. Repeatedly, he would explain that he was looking for something not actually written down, but the answer key that he used to grade would not reflect this.

Secondly, there is no feedback for students. While he does have a grading rubric on Gradescope, which helps somewhat, that's it. He will go over the exam once, and with COVID, I had great difficulty attending live lectures leaving me in the dark. Furthermore, he cuts out portions of his lecture from the recordings, explaining that he wants it as an incentive to attend the lectures. Well, that would be great if it was actually possible for me to do so. Additionally, he has a draconian regrading system that seems like it's meant more to discourage regrades or discussion instead of discovering faults in his grading scheme.

The third and final major fault with this class stems from a fundamental issue of the Professor. No one knew what he wanted us to learn. Discussions comprised a series of practice questions that we would do in groups, the book had some topics, and his lectures would cover the book for the most part, but he would occasionally segue into other topics for 5-10 minutes. Those small tangents appeared on the exams. This was extremely discouraging for me, and my friends and I wondered what was the point of studying, reading the book, or attending discussion if he was going to test on 5-minute topics that we covered once.

All in all, do not take this class if you can avoid it. While Chem 20B might actually be an interesting class with another Professor, this class killed any enjoyment I had of chemistry. I firmly recommend never taking a class with Professor Barr if this is the level of instruction one should expect from his classes. Reading the textbook on your own would both be more entertaining and more helpful that this course was. At least I learnt something from reading it.

Practically disregarded all of my other classes just so I could study chem for hours every day and then still fail both midterms, which had almost zero relevancy to the course material. Often, I can appreciate professors who give "creative" questions on homework or tests, but there's a difference when these questions are just plain vague. I've been to many office hours where even the TAs were struggling through practice problems because each one requires you to make about 10 different unrelated assumptions to solve them. Attending office hours is pretty much a requirement for this class since Barr simply refuses to give answer keys for his insanely hard problem sets (which are not even completed for any credit to begin with). I know a lot of people complained about both of his midterms, so the final was a bit better and somehow I ended up with an A- in the class. I'd still be wary though, as his questions are very inconsistent. Also, he speaks soo much about how much he "empathizes" with us but in reality, does not respond to valid inquires about his grading system, class structure, or difficult tests on campuswire or in emails. Avoid him if you can but if not, best tip is to try your best to get through his problem sets.

Barr emphasizes learning and accompanies that with a lack of teaching. The way he lectures seems somewhat coherent (like content wise it flows) but he barely teaches. Its not that he assumes that you understand hard topics he just states them randomly, pretends to explain, and then talks about how he values education and the "learning process".

If you do well on at least one midterm and mediocre on the final you should do alright in the class but it will be miserable. He doesn't ever post answers and gives lots of problem sets so it easy to get lost and behind. Overall, if you're looking at these reviews, you're probably gonna have to take the class anyway so brace yourself. If you don't understand anything, I promise you are not the only one. Go to your TA's office hours (they give a lot of answers / help) and just ride it out.

This class is hard. avoid. The exams are unnecessarily difficult. prof literally does not give answer keys. He really likes group work. He will call on you in office hours. Honestly, the only way to survive this class is do all your other work and stay on top of the problem sets. Go to ta office hours.

Professor Barr is an excellent teacher, but this was his first time teaching a college class. There were a lot of issues with the class structure, no doubt. But overall, I learned a ton, and I was able to perform very well in the class.

Few things to note:

- You'll have to work hard to do well in this class. Do the problem sets the week they come out. Go to office hours whenever possible to learn how to solve the problem sets (he doesn't give answer keys). Read (or at least skim) the textbook, and do textbook problems before exams. All of these things will pay off tremendously when it comes to exams.

- Exams were very application based for us. We complained heavily about this as they made exams difficult in the time provided, and for our final exam, he changed the exam such that it was not very application based. Made it WAY easier for us. He will likely continue that trend for you all. Should make things pretty nice.

- Try to enjoy this class. Professor Barr has a nice sense of humor and a quirky energy to him (he has an excessive love for Disney, for example). You'll learn a lot of cool stuff. Barr tries to make the applications interesting (and although that made things more difficult for our quarter, it'll likely be better for yours).

- NOTE ABOUT THE GRADING SCALE - THIS IS IMPORTANT! Barr has a very skewed weighing system. Exams end up making up 62% of your final grade (and 6% of the exam grades are group midterm grades - this means you go back and REDO the midterm exam with group members and submit one exam together, which is worth 20% of your total score for that midterm). 38% of your grade is based on gimme easy points (homeworks, OWL assignments, participation / attendance in discussion, completing mandatory surveys on CCLE, etc.).

He ALSO shifted the scaling system such that some type of A (A+, A, A-) is 88%+, B is 75%+, C is 63%+, etc. to work out in your favor. I was able to get an A+ even though I technically got a B on a midterm and As on the other midterm and final.

- He gives 5 points of extra credit on exams just for writing out a statement / signing your name and assigning pages correctly on Gradescope. Helps immensely (midterms are out of 100, so 5 points goes a long way).

Take all of the other reviews here with a grain of salt. Barr is a great guy, and this class will be nice if you put in the necessary effort. Enjoy!

I actually enjoyed the class throughout unlike most people in the class it seems. Barr is a great lecturer, teaches clearly, and cares very much about his students. The midterms were difficult, and the final was easier. The final score can replace one of the midterm scores. Although the tests are hard and the class freaked out, the averages were not bad and with all the other components of the class buffering your grade, it's not bad at all. Your final grade will be fine.

For this class I only rewatched lectures and hw Before tests and that was adequate. So I want to say that If you fully understand the lectures and cam solve the hw problems, you should do great in this class. You won't necessarily do amazing on the tests, but it will be good enough to get a good grade in the class.

I usually never leave reviews however after scrolling down all the comments, I had to do one myself. I agree that he isn’t the best Professor…it’s hard to learn the content the way he lectures and his tests really don’t reflect what he teaches in class. He has inflexible office hours however very important to attend to get the solutions to his extremely confusing problem sets. However I feel y’all are over exaggerating on this class… it’s fuckin UCLA and if you can’t handle this class then you’re going to die in your future courses. Yeah I hate him as a professor but not a bad person. I think he is just really excited to teach and likes to go out and beyond what you are supposed to learn. If you have him in the future, I suggest rewatching his lecture videos that he posts online and really take down every single small detail he says in them b/c he loves to use those small details for his tests. Problem sets help a little, not really but they are still good practice before exams. It was rare that i saw a somewhat similar question on these sets on a test, however maybe like 1 part in one of his long ass FRQs. Instead of just trying to remember content like vocab you have to actually understand what you are doing so when you’re doing stupid problem sets or review questions don’t just write them down, know the underlying topics and things that go with those questions. Overall, would never ever take this course with him again lol but if you have him good luck.