I spent basically one day a week to do gen chem and bio hwk, with lots of breaks and my 3 year old distracting me. I also spent 1 evening/wk doing "catch up".
Most of that time was doing lab reports, for me, for some reason getting my data just the way my instructor wanted it took FOREVER, and bio also had some research to it.
Studying for class: my chem instructor had spectacular structure to his course, so if I did the hwk and quizzes the way he wanted, my study time for exams was minimal (less than 5 hrs/exam). For bio, I read the chapter and did the quizzes that came w/ the book (online), total time, maybe 10 hrs/exam.
I skated by, I think, on less time than others because I took orgo before I took chem II and bio II, and a lot of questions/topics already made sense to me because of that. On the other hand, I had to do zillions of problems in organic, and ate, slept and breathed organic, because I hadn't taken bio II and chem II when I took it.