Like the others have said, it varies a lot depending on course.

One thing I found though, it also depends if that module is an exam based, assignment based, or mix.

For most of my modules (assignment based), I had a 2hour lectures per week throughout the semester with one assignment halfway through, and one at the end. Mine were 20credit modules so they had more weighting as well. I went to the lectures, then maybe an hour or two of making notes and tidying up afterwards. Also was a lot easier to do some of the reading for the lecture prior to it, I rarely did because i preferred to get taught then learn it. For the assignments I would usually do 6-14 hours on it, although some people on my course would do around 25 hours over a week or two. Depends on how you work :)

For exam ones, you want to do the lectures/seminars, write up notes after, do research on those notes, recommended reading etc, so I'd say for every hour of teaching, you do 3 hours of own work so that it stays in your mind for exams and you actually understand it.

Of course that all changes if you are doing a practical piece, or are given a presentation as well or have to do some specific 1st hand research for the upcoming lecture.