I took this class Winter 2021 which was virtual and I believe his first quarter teaching. I thought he was very nice at first. He seemed very caring and genuine. Turns out that was all fake and his class is tough af.
His lectures aren't that bad but pretty fast paced. He assigns problem sets that are optional. Homework is assigned every few weeks and is a few questions from the last problem sets. The issue I have is that he doesn't give answers to the problem sets, which really made it hard to be motivated to do those problem sets, since you don't know if your answer is right. The class asked him to provide answers and he said he wouldn't because "we wouldn't collaborate with each other" if he provided answers.
The homework also must be done as a group of 3, with all 3 people working together on the same assignment. My group was great and very helpful, but this could definitely be a big problem if one of us was international, or if one person just didn't want to work together.
He said that the test would be easier than the homework many times, but it was much much harder. He made up scenarios that don't exist and asked us questions on those scenarios. I do have to give him credit for designing these problems, but it was super tough. On top of that, he required that we all be on zoom during the midterm (we could have our cameras off thankfully) and he made changes to the midterm while it was happening. But how he did this was by sharing his screen of a google sides where he just wrote a sentence with the change. He didn't announce it or anything, so if you never looked at the zoom, you were just screwed for that question. He also made the midterms a two hour block with no alternate times at all. This screwed over some international students and his solution was to empathize with us and do nothing.
Overall, I would definitely not reccommend this class to anyone. He is super fake, and says "I empathize" about 100 times but doesn't care at all. Maybe he will improve in the future, since he was new, but I would not take Barr if possible.

This guy is crazy!! he's a complete pretentious weirdo. he pretends to be happy-go-lucky and helpful but in truth he DOES NOT CARE. (especially for international students) .This class is so confusing because he made it so. he is all over the place: HW is on diff platforms, surveys etc. his expectations are absolutely unrealistic!! he basically expects you to do the problem sets during week and then discuss your doubts in offcie hours as he does not give u an answer key. and he is stupid enough to think that all 300-400 students will get their doubts solved in office hours.

he rushes over the slides and doesn't let u cross question. (GREAT!) . he doesnt explain the concepts in detail and OMG his questions on the exam are so f***ing vague! dont be surprised if u get some completely new concepts in the paper, something you havent studied at all. I HAD to PNP this class coz i dint want a b+. This guy needs to get his shit together!! ull be very frustrated dont take his class!!

I was told I would get some flavor of an A, but all I ended up receiving was some flavor of trauma. I have no clue why this man never released any of the problem set solutions. All of my learning came from the review sessions that were good for the first couple of weeks but became more confusing as the weeks went on. He expected us to go to office hours to go over the solutions to problem sets, but I was always busy with extracurriculars at those times. If he really cared like he said he does, he would have at the very least recorded the office hours instead of inhibit the success of students who had other time commitments. Also, I think I can speak for most people, but I hate when a professor speaks to his audience like they are elementary students. This man has ruined my childhood Disney memories.

Every lecture 50 minute lecture felt like 2 hours. I would be completely lost in a lecture thinking it must be over soon and still had 35 minutes left. This was my last quarter taking chem and honestly it was a huge relief after the final because I knew I passed and did not have to see this man again. I hope I never have to hear another word from this man. Frick buffers and frick this man and his catfishing syllabus picture. He looked nothing like I thought he would.

If you're debating whether you should take this class, DON'T! If you can take it at a community college and save yourself the pain of not knowing what is going on at all times. Even when you think you got a topic down, he somehow finds a way to show you that you don't because his questions are all stupid and no one wants to take a midterm and have to answer a question about their professor's weird habits. Anyways guys that's a wrap see you guys in therapy F this class.

don't take this class

Prof. Barr seems to care more about his "[sic] pedagogy" than his students' well being. You will hear him throw this word at you about a hundred times throughout the quarter.

Other than that, you can expect an absolute minefield of insignificant assignments scattered on multiple platforms with next to no reminders/announcements:

1. OWLv2 assignments (very basic stuff but you'll probably miss a few)
2. Google Docs discussion assignments (won't miss them if you go to discussions)
3. CCLE surveys (about how good his "pedagogy" is, and you'll probably miss a few)
4. CCLE lecture quizzes (will probably miss them even if you go to lectures)
5. Gradescope group assignments (won't miss them if you have a good group)

... and 4 types of lectures:

1. Normal lectures
2. Discussion sections
3. OH (if you want answers to anything, you must go)
4. Review sessions (same as above: if you don't go, no answer sets)

... of which the latter two are not recorded because of his "pedagogy".

At this point you should see that Prof. Barr's "pedagogy" is extremely unforgiving when it comes to participation. If you do not stay on his track to the exact hour of the day, you will suffer. In other words, if you are distance learning from the other side of the world, or if you prefer to self-study asynchronously, you will suffer.

Either way, your suffering is insignificant, because his "pedagogy" is far more important.

I think part of the problem is that there's so much material to cover for a 10-week course, and the quarter I took it was the prof's first time teaching this class. He expected more from us than we could give, and I feel like a lot of the things he called "optional" (like the problem sets, going to office hours, etc.) were pretty much necessary if you want to do well in this class.

His lectures are mostly well put together and he posted lecture guides on CCLE that we could use to follow along/write on, and he seems passionate about the subject and teaching well. At the same time, it feels like he's a bit out of touch with the experiences/knowledge of undergrad students (I took this class as freshman in second quarter), and his tests felt like they were meant for people who had much more practice/familiarity with the topics than I had. They were tests that required you to apply what you learned, which is somewhat unreasonable in my opinion when we only cover a topic for a week before we have to keep going. The wording for his tests felt ambiguous to me, and sometimes I interpreted his questions in a way that was totally off, and I feel like if he used slightly less technical and "open-ended" language, it would have been so much clearer.

He did take a lot of time to grade our tests (as of writing this, our finals still aren't graded the day before classes start for spring quarter), but I feel like there is very little feedback on our work. There are four homework assignments, but those were group work, and he doesn't post answer keys for his problem sets (which are hard and time consuming, by the way), so you have to go to office hours and ask about each individual question if you want to know if you got the answers right.

TLDR: I feel like Professor Barr is a really nice person and he has the capability to be a great professor, but his expectations for students and what he can achieve in the class need to be reevaluated. His class is stressful (esp his tests) and takes a lot of time and effort, but he's not the worst professor you can have for this class imo, since the material itself is part of what makes this class so hard.

i still havent figured this guy out

Pain. Don't subject yourself to this.

Best professor at ucla. Do not hesitate to take 20B with this Disneyland legend. The man, the myth, the SHAQ DIESEL. Never had a better teacher, friend, or foe better than Dr. Kris Barr. He dances, plays Dungeons and Dragons, and uses Dove conditioner. TAKE THIS CLASS.

"Believe in the future. The world is getting better. There's still plenty of opportunity. A lot of young people think the future is close to them and that everything's been done. But this is not so. There are still plenty of avenues to be explored."
-Dr. KB

if you're taking this class, don't despair! it is a huge learning curve to be successful, but you can make it through. some tips: don't read the entire textbook, scan and look through the summaries at the end of each chapter. do textbook problems and all the problem sets (most helpful!!) also chem tutor on youtube and libretexts are great resources. it does take a lot of time since the course is incredibly fast paced (2-3 chapters a week first half of quarter then it did slow down a bit to 1-2) but honestly the group chat got me through this class so definitely don't be afraid to reach out to people because I guarantee you're all struggling together :)