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.

Professor Deifel is hands down the best professor I’ve ever had at UCLA. I’ve now taken three classes with him (Chem 20B, 30B, and 30AL) and each time, I’ve come away learning so much and actually enjoying the process. He’s incredibly passionate about chemistry, and it shows in the way he teaches and interacts with students. He makes challenging topics approachable and never makes you feel bad for asking questions.

What stands out most is how much he cares about his students’ success. He’s super approachable during office hours, always happy to re-explain concepts or just chat about chemistry and life. His lectures are engaging and filled with helpful insights that connect the theory to real applications. Plus, the labs are structured in a way that you actually understand what you’re doing rather than just following steps.

Even when things get hectic or disorganized (which is common in any lab course), Deifel is always flexible, understanding, and willing to adjust deadlines to help students. If you ever have the chance to take a class with him, I cannot recommend it enough. He’s truly one of those professors that makes a lasting impact on your education.

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!

Deifel is one of the best teachers I’ve had. It is clear that he genuinely cares about each and every one of his students. He makes himself available for all his students to address any questions or concerns. Deifel is funny, engaging, and made me excited for the 8am wake up (I know it’s crazy). He is incredible 10/10 experience.