Do not do it. Not worth it. If you can take the honor chem class, do it but do not take him at any cost. He does not explain well, he reads from presentations that are not clear at all. He does not explain how to solve things. I stopped watching his lectures from the 3rd day and had to stick with youtube (I was not motivated to read the book but others did so I can't judge) so basically, I had to self-learn everything. The first midterm was awful and the second was better. The final was so bad. I cannot talk for all people but I had little background in chem so I was below average in the class. However, I did slack off at the end so I believe that If you worked your best you will be able to do well somehow.

Avoid Prof. Felker and let me tell you why:
1. His lectures are very conceptual
2. He never goes over homework or tells you how to apply all the formulas and theories into problems.
3. The wording of some problems on the tests is unconventional and designed to trick you as if he intentionally wants you to get a bad grade. The problems themselves are not hard but it takes forever to understand what it is saying. I understand that chemistry is supposed to be hard but getting a bad grade just bc of the unusual wording is not quite acceptable.
4. The online learning program he requires has a bunch of typos. I hate the feeling when I get stuck on a problem for a long time and start to doubt my intelligence and then find out that it's just that the answer key is wrong.

But there are two things about Felker that I have to defend. I see people complaining that there is a lot of math involved in his hw problems. I hate math too but hey it is a college level chemistry and it is supposed to have this much math. I don't think Felker should be blamed for this one. Also people say that his lectures are boring. Again it is college level chemistry so the lectures are supposed to be boring (physics lectures can be interesting but I've never seen a prof who can make their chem lectures not boring).

Try to avoid taking his 20A. But if you really have to, make sure that you took AP chem in high school. 4 or 5 on the AP chem definitely helps you understand his stuff better and makes your life less miserable.

Avoid Felker at all costs. I have no clue how I got an A- in this class since I did not learn anything from Felker himself. Honestly, not watching the lectures and teaching yourself through the book and any other method of learning about chemistry was much more helpful. The lectures consisted of him reading his notes that had almost nothing to do with what you were tested on. Office hours and TA sections were equally as vague to the point where some of the LAs for the class were confused about the material. Take literally any other professor.

I had to take this professor because there was no other option. I knew going into the course it would be a struggle. Add covid and the fact that the class is remote and you have straight up hell. First off his lectures, they were all recorded so I had to find the time to watch them. They were messy, confusing and SOOO long. Eventually I realized they did not help me at all and stopped watching them. After the first midterm I realized OWL was my best friend. Just redo the problems over and over again because some of them would pop up on the exams. I basically learned all I could from the problems and youtube. Going into the first midterm I felt like I was prepared because I had watched every lecture, done all the OWL problems at least 3 times and watched a lot of youtube videos. I did average (and average was very very low for my lecture.) So going forward I ditched the lectures and just focused on OWL. I got covid right before the second midterm (I was hit really hard) and was basically begging him in a email if I could have extra time because I couldn't even get out of bed or move and he responded with. "If you don't take it you will only have the midterm and final as your grade." This scared me so bad that I just sucked it up and took it with a 103 fever, chill and all else that comes with covid. I felt so distant and unheard. I get it college professors aren't going to hold your hand when you feel bad and have a million other students to consider too, but like WE ARE GOING THROUGH A PANDEMIC. The final was brutal. There were things we had never seen and never learned. I had spent so much time studying for literally nothing. This class was just awful, but join the Group Me and try to find support cause I guarantee everyone else is struggling too.

I'm guessing if you're reading these reviews, you don't have much of a choice.
- Lectures: I didn't really bother to watch any of the lectures because a good amount of people said they aren't really worth it. However, I had a very solid background in chemistry going into this class, and did well in AP Chemistry, so that prior knowledge helped me. I heard that he goes further in depth about the conceptual ideas of the course, but the tests don't really have many in depth questions of the concepts. I taught myself and relied on outside sources (the Organic Chemistry tutor is amazing) as well as the textbook (sometimes) to teach me a lot of the topics I didn't already know.
- Assignments: In my opinion, the assignments are doable and the workload isn't as bad as it could possibly be. The weekly assignments you have to turn in are graded off completion. We also have to do OWL, which is essentially end of the chapter questions. These questions were the main resource I used to prep for his tests, because they actually teach you how to do the math and apply the concepts. Sometimes he even pulls questions from the OWL assignments for the midterm, so I would make sure you thoroughly understand how to do them.
- Tests: I thought the midterms were alright, but he only gives you an hour. He did this to try and prevent cheating but lots of people barely had time to finish. There were only 4 questions, sometimes with a few parts (like a to b or c), but if you screwed up one question, it dropped your grade significantly. The final was insanely long in my opinion, and a bit more challenging.
- Other stuff/suggestions: Felker isn't super approachable, he didn't help us meet others in our class, definitely join/make a group me (that gc taught me more than Felker), there's a curve at the end of the class (but doesn't help much).

To those who plan on having Professor Felker for Chem 20A,
If you can, try avoid taking Felker. Although he is certainly not the worst professor ever, his lectures can get technical and somewhat difficult to understand. But, as long as you try to understand the gist of what he's saying (just don't try to understand all the details, just learn the big ideas), then you'll do fine.
Here, I will list why you might want to avoid taking this class:

1) His notes are either typed paragraph-form essays (and trust me, it's hard to take concise notes when there are too much information) or (in later times) sloppy cursive illegible handwritten notes (he used this in the last three weeks, when that information was going to be the primary focus for the 35% final), and 70% of his talking is just directly from the notes, so you might as well think of his lectures as a monotonic audio-version of his terrible notes. Just do yourself a favor and take notes from the notes/textbooks instead. He has no originality in clarifying the concepts, with his monotonic that would almost make one fall asleep in 30 minutes, and talks to you as if you are some graduate student who knows almost everything about chemistry (hello, this is GENERAL chemistry, not specialized chem!). If you took AP Chemistry, then you would have some advantage because some content will be a little familiar; otherwise, it will be a true struggle...team up with knowledgeable people on GroupMe and you will get through ok :)

2) Only the first three weeks is review basic chemistry from high school and the first midterm is based on that, so you better get the best score you can...because after that is quantum chemistry, and it is so complicated (and the professor explains it very confusingly) that after that, almost nothing made sense to me. You will spend 3~4 weeks learning this nightmarish topic so be prepared. Everything from here was terrible; quantum chem was too complicated, organic chemistry involved too many names/types to memorize, and transition metal compounds was the epitome of the terribleness of Chem 20A.

3) You’d think that since the COREQUISITE for this class is Math 31A (AKA Introductory Calculus), so the math discussed in lecture should be fair and easy, right? Wrong! This professor mentioned so many math concepts that I have never seen before, including partial derivatives (Math 32A), multiple integration (Math 32B), complicated differential equations (Math 33B) that the lecture notes became confusing and incomprehensible. The only lucky thing is that the tests themselves have no calculus involved, but still!

Here's the good news: The only lucky thing is that the tests are curved in relative terms, so it will help you compared to absolute percentages (unless your class is really smart for some weird reason). FYI, most of the tests had 80% averages, and the professor said that the average overall grade for the class will earn a B.

I am very sorry if my ranting was very long, but hopefully this gives you a better picture of this class. The only reason why I scored an A- (if you care) was because I took AP Chemistry, listened to the boring lectures (even though I hated it), and studied past exams and OWL problems (PLEASE do this, it will really help you in the long run). I sincerely wish you the best of luck and prosperity despite the most brutal experience as a freshman.
Note: I re-edited this review because I eventually realized Felker was considerably better than the professor I had for Chem 20B: Professor Barr. He was way worse than Felker (see his reviews)...

Professor Felker...was a handful. His lectures are slow and ridiculously unclear, talking to his students as if each one has a PHD in quantum mechanics along with all of his lecture slides displaying the information in one giant cursive handwritten paragraph. A paragraph. In middle school the one thing they teach you about presentation making and displays is short and sweet- bullet points and clarity are essential, but Professor Felker must have been absent that week of 6th grade, for every presentation he gave consisted of dense paragraphs of his chicken scratch. However, Felker's fatal flaw was his testing- absolutely brutal. Professor Felker would spend the majority of his lectures going over strictly conceptual components of the material and then test you on all of the math that he failed to cover. Tests often had averages of a C/D and overall grades depended on his subjective curve that only applied at the end of the quarter- so the entire time you had little to no idea how you were doing in the class. The program that he uses for the textbook and homework, OWL, was incredibly dense and begrudgingly long, but worst of all, sometimes just plain wrong! And if the textbook is wrong, the professor clueless, and the TA's are unhelpful, your success in the course is pretty much left to fate. Overall, avoid Felker at all costs, it is surprising and a little bit concerning that this man is still teaching at such a renown school. If you have any other choice for a professor- take them now and don't look back- but if by default you end up getting stuck with Felker, well...Good luck Charlie.

I took this class online during Covid. It is solely based on one midterm (35%) and one final (65%), which is ridiculous. The notes he provides are very sloppy and handwritten in cursive. He has things scribbled out and arrows pointing to where things should be written. He just reads off his lecture notes but he jumps around when talking so it's hard to figure out what he's saying. He assigns about 20-35 HW problems per chapter but they are not graded and are not too helpful when it comes to preparing for the test. His tests are ridiculously hard and nothing like the HW problems. His office hours aren't of much help as he just explains everything the same way he does in the recorded lectures. Class averages on tests are around 50-60% and he seems to be proud of that as all he does is brag about that and tell us that we need to be prepared because the tests are "hard."

Honestly, while people give this dude shit but he wasn't as bad as they say he was. Ok,
so this is the structure: his lectures are boring but oftentimes really helpful, midterm 1 is hard but somehow midterm 2 was easier (the class average shows this), and the final was somewhat challenging, the OWL questions are way too buggy and wrong too often so be sure to check that the method they use is right all the time, discussions can be skipped and just need your work to bee uploaded on grade scope. The TAs are very disorganized in this class and still can't decide on what the right answers are so be sure to use the regrade request constantly on grade scope. He is accommodating because I remember that people weren't able to submit their papers due to technical issues and he did allow retries. But be ready for some dull lectures that are being read off slides and some horrible grading attempts. This class was conducted in a pandemic and I can genuinely say it taught me a lot, but I can never understand what I'm supposed to do with this knowledge because there was no application-based learning. Btw you need these fundamental concepts for upper div chem only so get credits for this class if you can and if you are sure you arent taking these upper div classes.

I want to say that the grading of this class makes up for the professors teaching. That is not to say that Felker is a bad teacher, going to zoom office-hours he seemed to be pretty helpful with answering questions as long as you were extremely specific about what you were asking. Still, his zoom lectures were incredibly confusing, and his handwritten notes made me feel like I was taking a cryptology class.

Going on to the material of the class, it is nothing like AP-Chemistry. I would say that AP Chemistry makes up for 15-20% of the course itself; however, the course goes into the math behind the wavefunctions of the spdf orbitals. Although, regarding the math, you will not need to derive or understand the complex math that brought you the wavefunction, but you need to understand what the variables of the wavefunction mean and the relationships that entail.

Finally, and most importantly, to do well in this class, never miss a homework assignment and study the shit out of the OWL Questions. Although Felker is a difficult Lecturer, the fact that he uses OWL Questions for midterms made this class a little bit easier. Study the shit out of the OWL Questions and end of Chapter Questions, and you will be fine. For the Final, there are not any questions that you can study that would mimic the questions that are on the Final. Use OWL and EOC Questions to study solving methods, but make sure you understand the material that supports those equations and solving methods. Other than that, go to your TAs for Final review as they will probably be more useful than Felker's office hours.

Overall this class is challenging, but it can be manageable. Try not to slack off in the beginning otherwise you will be struggling to clutch it up in the end.