I never took Chem until college, but I still escaped with a B and B+ in the 20 series. I had Beren for both classes, and he was excellent. 10/10 would recommend

Go to office hours and if Jesus is your TA, go to his section and his review sessions. Beren cares about his students and wants you to do well. Take him!! He's super sweet, is very passionate about what he teaches and I loved having him for 20A and 20B. Do the discussion worksheets and the homeworks and take notes, as long as you stay on track with that plus a littel studying, you will do great in this class. I only took HP Chem in high school and I was able to well and I know I could've done better but I made stupid mistakes on the midterm and final (which were both very fair).

If you ever can TAKE him for 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.

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.

Beren is a really good teacher and in general a pretty chill guy. I don't think you're gonna do any better for Chem classes. HW closely resembled exams and the exams were pretty reasonable. Only thing I'll say is the second midterm was way harder than the other tests. Don't underestimate it. If you're confused, go to office hours, it's very helpful.

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.

Beren is super friendly and a clear lecturer

First of all, this was the BEST chemistry class I've ever taken. Christian really cares about his students. First day of class he made sure everyone could make at least one of his office hours. He has office hours every day and holds one or two review sessions before each exam. The tests are pretty challenging but they're completely fair.

From what I can remember the grade distribution is about:
85% tests (2 midterms and a final)
15% homework
There are only 5 or 6 homework assignments, which aren't busy work. They're about 6-10 problems that you have about two weeks to do. They're great prep for the test. Office hours are super helpful and I actually showed up to every MWF 8am, so you know the lectures were good.

Overall I genuinely enjoyed this class and got a very conceptual understanding about thermodynamics. I would definitely take a class with him again.

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