I'm on the quarter system, so our summer quarters were 10 weeks in length just as our other quarters are. For organic chemistry, 2 labs a week = 2 lab reports. For quantitative analysis, 1 lab a week = 1 lab report, same for physics. It just depends on how many days you have lab.
I heard that it's really hard for those on the semester system to adjust to the quarter system's short schedule, so good luck!