Can I just show up to a different tutorial than the one I was assigned to, and still get participation marks?

Depends on the course.
For Chem, yes.

Social sciences.

Generally, because the beginning of the year is the drop and add period, changing tutorials is allowed. Sometimes some are more crowded than others and professors ask students who are willing to move to do so.

Some of my Social Science courses had attendance in tutorials, and others didn't, but if there was room in the tutorial and you asked to switch then it wouldn't be a problem usually

Ok that's good! Thanks, everybody