Professor Deifel is easily one of the most caring professors at UCLA. He takes the time to learn each of his students' names, and he makes himself available even late during the night to help students. He is not only passionate about chemistry, but he is passionate about making sure that all of his students succeed. In terms of grading, Deifel made it very easy to earn an "A." Half of your grade is determined by homework (based on completion, not homework) and attending discussions. The other half is based on the final and two midterms, which are pretty reasonable in difficulty. Overall, I'd 100% recommend taking this class with Deifel!

Diefel is exceptionally enthusiastic and it is apparent that he is passionate about what he teaches and genuinely cares for all of the students. He's pretty humorous, which made his lectures engaging and enjoyable. I found the materials covered in this class to be pretty tough, but this has more to do with the nature of the subject, and Diefel does his best to make the best out of the experience. 50% of the grade comes from homework and attendance, and while the homework on the Owl can be convoluted and not always relevant, it is easy to get 100% on them. His midterms are fair and he always hold a review session before each. Overall, his class was one of the most enjoyable that I have taken in a long time and I would definitely recommend and gladly take again.

One of the best professors I've ever had. Very knowledgable in chemistry and has genuine care for all his students. Midterms are fair (not too hard, not too easy), and if you are ever struggling with a concept, Professor Deifel holds office hours throughout the week and is very responsive. He does an excellent job preparing students for the next class in the Chem 20 series. Would 100% recommend taking his class.

Professor Deifel makes chemistry at 8:00 AM not only bearable but actually enjoyable. Homework and participation account for like 50% of your grade, both of which are easy to get full credit on. The midterms are fair and he gives a detailed review session telling you exactly what to expect. He is always willing to hold office hours and is incredibly responsive to messages. Overall, you can tell that Professor Deifel is quite devoted to the field of chemistry and his students, making his Chem 20A worth taking.

Very engaging lectures and a great teacher. Has helpful reviews before the tests and lots of office hours for extra help. Cares about students learning and provides many resources. I don’t like chemistry much but found this to be one of my favorite classes.

I took 20L with him Summer 2025 (maybe I'll transfer this review once he gets a 20L page), and it's safe to say that Deifel is quite literally one of the most caring and loveable professors I've had here. He's funny, overshares (in my opinion, a charm) about his life, and genuinely engages with his students. I've never met a professor who cares so much about his students' success. Yes, he challenges us, but fairly. He has literally 10+ office hours a week, which I HIGHLY recommend taking advantage of, because you get to know him well and get to understand his personality and course content.

Since our class was small, Deifel was also our lab section lead as well (as opposed to a TA), and those were so memorable and fun, despite labs being stressful.

However, more about the class, it's a fair class with not too much work, given that 20L is a gen chem lab. He often does things his own way, which can sometimes be confusing, but just communicate with him, and he'll understand. He is also super chill, so I would try not to stress much during this class, especially if you put in the work to succeed. This is not a class you can slack off in, but definitely a class that is manageable if you are taking multiple classes (during summer).

One thing about this class I loved: it was so collaborative! I genuinely felt like working with the students in the class, as Deifel fostered that community. I never felt more supported by peers, especially when I was confused about lab write ups.

Anyways, just take this class with Deifel if you can! Or any class with Deifel, to be honest. Deifel Deifel Deifel!

Deifel is a very helpful guy, holds lot of office hours and is always open to questions from text. Lectures are engaging and Deifel is overall a very nice and helpful professor for what is a class that has difficult material.

He's a very fun professor, he has so many office hours and is free whenever to help students. He's very passionate not just about the subject but also about his students and gets to know almost every one on a more personal level!

Dr. Deifel is a godsend. I cannot express how useful his lectures are, the clarity of his lessons makes chemistry easier to understand. The nature of this class makes it challenging in itself, however, Deifel will hold you by the hand throughout the quarter and answer questions if you show up to office hours. Homework and participation are worth essentially 50% of your grade. Plus, the exams are relatively difficult but straightforward, so you will get a good score if you study. Definitely take this class if you can.

The lectures are important, but it takes personal devotion to truly know the material.

You don’t have to read the textbook to get an A, but you will need to spend some independent time learning in some form (Organic Chemistry Tutor FTW)

Deifel is really funny, and he really keeps the class engaged. Although it is my hardest class this quarter, I always look forward to coming to class.

His review sessions before tests are a godsend. If he didn’t do those, succeeding before tests would be a lot harder for me. The tests are hard, but he puts his best effort into being a highly valuable resource to you. Thank you Deifel!