Beren was very considerate considering whole coronavirus situation and the sudden switch to online learning. The notes that he put on CCLE were very organised and really helped with understanding his lectures, which were also very organised. His exams didn't throw out any curveballs; as long as you studied the material, did practice problems, and understood the concepts, I think you should be fine. For this quarter, all of the exams were take home and we had about 48 hours to complete them, which is definitely more lenient than during normal chem 20B classes, so that might be something to keep in mind but overall I really liked this class, which is saying something since I hated chem in high school :,)

Beren is the goat

First of all, I got a C in CHEM20A with Christian last quarter, so don't let my grade scare you away from the class... I just never understood a thing about chem and had no background in chem. I wasn't expecting a grade any better than a C, and It's honestly a miracle I passed (C- is passing right??). Anyways, Beren is definitely a great teacher, better than the other professors available. Also the best TA is Jesus, and even if he isn't the TA for your discussion, you can always find his discussion and just join them (I did that for both quarters). Hopefully you do better than me!

Overall, if you're looking for a Chem 20B professor, look no further than Christian. This guy is an absolute hero, and I'd highly recommend taking him over any other professor if possible.
Lectures are not necessarily the best, as he spends some time going over derivations, while my TA told me to completely ignore the lecture on titration graphs, since those won't be tested on the exam. However, his lectures are Bruincasted, so make the most of that time as you will.
Discussion is EXTREMELY helpful, and I'd highly recommend attending. The LAs actually force you to do groupwork, and the worksheets help you practice and are quite good at getting you to become good at the concepts and skills that will be tested on.
The grading is 10-25-25-40 (your standard scheme), and it's quite good! If you are lucky with your TA, homework is graded entirely on completion (Christian reaffirms this also), so that's a free 10% of your grade already locked up. Watch out for the first problem set, which is usually disproportionately harder than the others, but that's a deliberate scheme by Christian to get people to come to office hours, where he's one of the best professors you will ever have. This guy is amazing during office hours, and will explain everything so clearly that some people walk out of there looking like they've just achieved Nirvana or something. The midterms are extremely easy (the average for the first was an 86%, while the second one had a much lower average of 71%, so watch out for that), but honestly, in terms of difficulty, as long as you study the topics they warn you to study, you should be able to score quite highly on both of them. The final is also very very straightforward, most people were leaving the lecture room after an hour and 30 minutes (we had 3 hours for the final exam), and this guy also curves the average of the class to a B+, so nothing to dislike here (also doesn't downcurve). Don't worry about being screwed by the curve, the curve is only helpful and will not negatively affect your grade in any way. Excellent dude.

Beren is probably one of the kindest professors I've had at UCLA. He has a really nice grading curve and says he made the median a B+ (which was a heavy boost since our second midterm had a D+ average). The exams actually weren't that bad, I think a lot of people just underestimated the class and didn't study that much for them. In general, he actually tries to make the homework harder than the exams, which is pretty nice. He had office hours 4 days a week and was pretty helpful in them. His lectures were pretty good as well. I think overall everyone loved him, I didn't really meet anyone that didn't like him.

I had a great experience with Christian in Chem 20B. Him, the TA's, and the LA's all worked together well to ensure everyone had a positive experience. He is relatively new to being a professor so he can make a few mistakes. However he has plenty of office hours, is very responsive through email, and is clearly very eager to do the absolute best he can.

I would definitely recommend 20B with him, as the class was not stressful, the homework was very reasonable, tests were fair, and he is working hard to improve your experience. He also is very open minded, and does a great job with showing you how 20B can be applied. If you do have him for the future, here's some tips:

-The first homework (diffusion, etc.) was very hard, but do not get discouraged. It is set up to be hard, and does not reflect the rest of the class. Also, this material is not ever tested.
-Personally, I did not find the textbook useful, just study off the notes and material he makes. He's not out to trick you.
-Go to discussions! Although they are not required, sometimes important things are brought up that aren't in lecture.
-Thermo is the biggest part of the course, really prioritize learning it.
-The class exams were significantly easier than 20L, so don't just study 20B stuff for that.

Beren is a great professor as always. I thought exams were pretty challenging, but TA Jesus' review sessions helped a lot.

I really liked Beren but he was not very understanding when it comes to tests. I messed up one part of a problem on the second midterm and he basically just made the whole question wrong which kinda wrecked my grade. Overall he's a pretty good teacher and is helpful if you go to office hours. Overall, I don't think you'll do any better for Chem.

There are already a ton of positive reviews about this guy here but I'm going to add one more anyways.

I took this class during COVID-19 time and Beren did an amazing job of handling the situation and providing extra help to students via office hours, email, and the class discussion forum/website. For the quarter he reposted all of his lectures for the class from the previous quarter, and I was pleasantly surprised to find that all of his explanations were so thorough and explicit that I rarely found myself in office hours. I took this class with only the background of Chem 20A and a high school honours chem class and had absolutely no problems handling the homework or tests.

This is the guy to go to if you want to enjoy your experience doing chem.

Prof. Beren was pretty good! He was very accommodating with COVID. The homework wasn't too heavy, and the exams were really easy (they were very similar to the homework). On top of that, the tests were open-note, open-book, open-internet, AND collaborative. Attendance to the discussion sections wasn't mandatory, either. Very easy class, very accommodating professor. If you took AP Chemistry and did well, this class will be a breeze for you either way.