I came into this course with a love for chemistry from my high school courses, but I had no way of expecting the level of stress I felt in this class. I felt that there were many elements of this course that made it much more stressful than it could have been. Firstly, what bothered me most is that Professor Barr never gave us answer keys for the problem sets he created every week. The only way to get answers was to go to his office hours Monday and Wednesday evening. However, not everyone can attend those sessions, so if you weren't able to attend you were doomed for the course as those problem sets were the only way people can perform well. He refused to record office hours and post them either even though they were the only way to answer his very difficult problem sets. In addition, while his exams were technically an application of what was taught in class, they were a constant stretch. Overall, Professor Barr's course brought me so much unnecessary stress that shouldn't be so prevalent in a general chemistry course. I would not recommend any student to take Chemistry 20B with Barr.

That being said, like someone else said, it feels worse when you're in the thick of it versus when you come out. I feel he was very kind on grading for the final, and he drops the lowest midterm so it often turns out alright in the end. Some tips for succeeding in the class:

1. Don't bother reading the textbook! At most, skim the chapter summaries. They're written so densely and probably won't help you much at all.
2. Start problem sets ASAP and go to as many office hours as possible!! If possible, ask friends to send you office hours notes on days you can't attend because they are quite helpful.
3. Even if you have no idea how to approach a problem, write SOMETHING down as Barr often gives you partial credit for the craziest answers haha

Way too many negative reviews just because people did badly on their tests. Definitely not the fault of the professor, since many of the applied questions were fair and directly connected to concepts discussed in lecture. Overall, Barr doesn't make this class easy, but that isn't necessarily a bad thing. I know I've ended up learning more with a harder class but many of my classmates choose to whine and moan about their struggles instead of rising to the challenge. I hope that these complainers are weeded out of chem/pre-med in the next few quarters so I'm not stuck with them for the rest of college. Overall, Barr is very clear in lectures and there are plenty of resources for learning: problem sets, textbook readings, textbook questions, discussion groups, review sessions, and a ridiculously huge amount of office hours. He's definitely a little goofy but that makes lectures a little fun. His tests are hard but they're certainly possible if you put in the work to understand his questions and definitely pay very close attention in lectures, which can directly tie into test questions. My only complaints are that he doesn't have a 12/24 hour window for tests and that he takes forever to grade stuff. Overall, hard but rewarding class. Don't let the number and the angry, dramatic students skew your perspective.

Honestly, Barr gets a worse rep than I think he deserves, but I do really disagree with the setup of the class.

He clearly genuinely loves teaching and chemistry, and he is always excited and helpful during office hours and after-class-discussion sessions. Doing well in his class takes a lot of work: all of the p-sets and as many extra problems as you can find, and especially reworking test-style qs. The tests are pretty arbitrary, but if you're familiar enough with the content and the style of question you'll get enough partial credit to be fine.

The biggest issue I have is that the pset answers can only be accessed through office hours. While I'm sure this policy increases office hours attendance and prevents students from just looking straight at the answers, it comes at a huge cost for students who have other responsibilities and cannot attend routinely (esp those with jobs, family responsibilities, etc).

I really believe education should be something that is accessible for everyone, and I think prioritizing anti-laziness for a handful of students who would slack off if the answers were posted rather than the access to education for students who are putting in the effort but simply cannot attend is not a great policy.

TLDR: If you have the time and availability to commit to office hours AT LEAST once a week, this class is a great way to push your chemistry knowledge and apply it to unique situations. If you are not in that position, it will be very difficult to get a sufficient education given the setup of this class.

With Barr, the way that he teaches is not like regular chemistry classes. The styles of questions of what people usually have seen in past chemistry classes are not the way he teaches--it's like those deeper insight questions found at the end of the problem sets found in textbooks. The way that I can describe him and the things you learn are very much applied like those fun chemistry videos you see on youtube or social media. He is a very engaging lecturer and has several opportunities for office hours and areas to help you out. However, his teaching methods are questionable when it comes to answer keys. In his logic, he doesn't post answer keys because he wants students to come to office hours to get them and to build communication and speaking the language of chemistry which to some extent is valid but is hard to do on our end esp when it comes to studying near a midterm/final. My advice for this is to communicate with other students and collaborate to make your own answer key by going to his office hours. Although his methods are somewhat questionable in that sense, it's very doable to work around. His midterms and final in the past have been tough but in my experience, these were actually relatively easier than the ones from the year before and much more attainable in the scope of this class in terms of expectations. While these assessments are really tough, he is a very gracious partial credit grader, giving points to things that basically made people pass midterms and finals when we probably barely had any idea what we were doing.

Final advice: going to office hours is a non-negotiable every single week if you want to succeed in this class and that being said the problem sets as well. Practicing previous midterms and finals from years past are a great method in preparing for assessments. Although this class is very tough, it is feasible to succeed but there definitely needs to be work put in past lecture and cram studying.

he curves way too well in the end, 90% ended up with A

He's the best!

Ngl, I think the reviews portray Barr a lot worse than he is, but also I think he's probs the worst prof I've had at UCLA. I despise how he didn't want to give answer keys to problem sets because he wanted students to go to office hours, which makes it hard to ask your question since everyone there wants to ask their questions. However, I think if I tried harder to learn the content I would've done better in the class. I just didn't like Barr that much overall so I didn't give the class that much time. However, I still did decently enough on both midterms and the final to get a B, and I liked the group midterm aspect too so I think that's why I ended up with a B. I think that if you can get over his personality and have a good TA to ask questions to, a good grade is achievable. Also, I had a great LA so shoutout to Tamara for helping me through this trying time.

i switched out of my chemistry major after taking this class

I took this class in Spring 2023, and I would say don't let the negative comments scare you. His class is indeed challenging but fair and manageable. Prof Barr gives little mandatory homework, BUT he posts many problem sets, and if you can do the problem sets, you will do good on the exams. I went into his class pretty scared due to all the negative comments, so I was doing the problem sets and going to some office hours and review sessions, which helped.

If you are going to take it, here's some advice:
-> Nobody (or almost nobody) reads each chapter before the class. I didn't either, but if you go with zero familiarity, you will be lost because the lectures are built on the assumption we have already read the chapter. 30 minutes or more of Khan Academy on the topic the lecture was going to be about will 100% help me to follow along with the lecture.
-> DO THE PROBLEM SETS. You don't have to do them all, but doing some problems here and there is super helpful. He even put really, really similar questions in the second midterm and final from the problem sets.
-> He has ZOOM office hours and solves questions in detail. I tried going to some of them and asking even the dumbest questions since it is on Zoom lol
Other tips :)
-> The TA's office hours were basically to compare answers or solve problems from the problem sets with other students.
-> Also, there were tons of review sessions in the quarter.

Overall, Professor Barr is a nice and kind guy who expects a lot from his students, especially proactivity. But in the same way he expects a lot, he provides many resources, take advantage of them, and GOOD LUCK!! :D

No. Absolutely not. Professor Kristopher K Barr is my worst nightmare that I would rather not wish upon my worst enemy. I feel joyous for those joining UCLA in 2023 for they shall be spared by Barr, while pity envelopes me for the students of his next endeavour.