Heres the thing, Barr is a professor people love to hate. Now would I say this out loud? No, no I wouldn't. But everyone else on here made him seem like the worse guy and teacher they'd ever met. Maybe its because I'm an engineering major and have delt with FAR worse but this man is so generous in his grading LMAO. For reference, winter quarter was the worst quarter I have ever experienced mentally. I was lacking in ALL of my classes and failed the first midterm. I watched all his lectures in 4 weeks, crammed, and I got a 60 on the final and like a 65 on the last midterm. I STILL GOT A B. I failed every quiz except for one. For the first midterm, I made up like all my answers on the test, EVERYTHING. Like not a single thing I put made sense or was correct and I got a 60 percent... This man grades so easy and gives so much partial credit and extra credit. In summary, do I personally like the man or the class, nope. But is his class super forgiving and generously graded YES! So don't be scared to take this class, I think Barr has read his horrible reviews from years prior and got his shit together.

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 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

i think after the horrible tests in winter 2021, he toned them down. granted they were still hard but it was mostly doable.

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.

Yeah... no

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

Ok this professor. WHERE DO I EVEN START. I definitely learned a lot, and I'm glad I did because I had Kavner before Barr and it was the worst, however, Barr was really engaging. You come into the tests thinking they're so hard and look back and see how easy it was. I averaged like mid 80s which was "Some flavor of an A". The quizzes tbh are harder than the exams. The first exam was super easy, it's just EXTREMELY easy to overthink simple things. Also, the TA's grade very generously. Like VERY generously. I literally got points for putting down something completely wrong (Literally said x=1) and got partial credit for an extra credit problem. Don't be worried, you'll be fine, Barr has definitely gotten better. He's like the Corbin of Chemistry but easier. Everyone loves to hate him but he really wants us to do well. His office hours are 1.5 hours but often extends it an extra hour just to go over problem sets, etc. Like its very clear that he cares about us. You dont need an A on every exam to pass, an 80+ will get you some type of A in the class (according to him), so don't stress. And no, you don't need to know anything from 20A to do well. You also don't need to read the textbook. I lived off of problem sets, and office hours. Looking at my grade, you'd think to not listen to me, but I make stupid mistakes on exams and it costs me so many points, I also happened to fail the first quiz (one incorrect answer messed up the rest of the parts). I think I was around an 87, when an 87.5 was an A- and an A was an 89, so not too far off, tbh I think if I wouldve gotten 2-3 more questions right on any exam I probably would've gotten an A but oh well. TLDR: You'll be fine. DONT fall behind and go to office hours. You'll survive.

I have never felt so miserable in a class.

Winter Quarter included the worst day of my life (and that's only ever going to be topped by my loved ones dying) and while I'm not giving Barr that much power over me, this class certainly didn't make that day or the aftermath of it any easier.

Honestly I would just recommend reading the Gatekeep, Gaslight, Girlboss review because it summarizes my feelings so well in a succinct and somewhat polite manner. My main take away from my quarter in hell with one Kristopher K Barr is that this man either enjoys torturing young adults, is straight up delusional about his own teaching skills, is secretly a Disney animatronic sent to kill us all, or all of the above. Sadly Barr is currently the only option for Chem 20B, which I sincerely hope changes in the future. All I can say is good luck, make sure to take care of yourself, and be prepared to suffer.

Barr's course is tough. He expects a tremendous amount of time and effort that not all students have. Aside from that, his tests and quizzes are extremely hard to study for since, for the most part, they focus on one concept. So, you either studied the right material or you didn't-- it's a gamble. He has three quizzes, two midterms, and a final-- one of the midterms being mid week 9. A huge portion of both midterm two and the final were concepts we literally just learned, leading me back to his high expectations outside the classroom. He uploads problem sets weekly but provides no answer key, forcing you to attend one of his not-so-helpful office hours. What does help a lot if his scaling. He scales all quizzes and midterms, so, if you get a 50 on all of his work you're guaranteed a C. Don't let him trick you though, his tests are rough.

Honestly this class was tough but worth the struggle. The class has asynchronous lecture videos and problem solving sessions during actual class and discussion time. Quantum is inherently difficult but Professor Barr, Pujan (TA), and the LA's were always available to help us answer any questions we had during class, outside of class, and office hours.