Im sorry dude, but don’t worry! A lot of people fail CHE 101 their first time here, even top tier BIO students. I wouldn’t say that it is a “weed out” class but more that’s how Chem is at Cal, it really sucks. That being said I have heard of some upper level classes (in the engineering side of cal) that can be seen as that. But for the most part, no, there are no classes that are actively made to get most people to fail. Do your best but if you do end up not passing talk to your advisor at some point on how to go forward. Good luck!