It's a lot of work, but it's really not that hard to understand. I aced my chemistry classes in college. The only reason my classmates didn't do the same is because they didn't review study along with studying current topics, and they didn't do enough sample problems either. The problem is it's a lot of work, not that it's hard. I think the main problem in chemistry classes is trying to jam too much material into one semester when not everyone has enough fortitude (or time) to spend on a single class. Professors themselves are often overcome with how much they are expected to cover in a single semester, often rushing though material in a way that can't be considered a learning process. I have had multiple professors tell me to keep studying after classes are over to make sure I am ready for the next class. I even study for classes before the term starts by finding the syllabus for the class ahead of time.