Chemistry 11:  Today I gave back a number of assignments that I marked over the weekend (U5 # 11,12,17; U5 # 15 a-c, and Lab 2E).  We did # 22 (any 8 problems), 24 (any 4 problems), and all of 21 from Unit 5; these are all due Friday.  We prepared Lab 4D for Friday, then we learned how to calculate percent composition by mass.  Due also for Friday is Unit 5 # 44 and 45 (any 10 problems).  We finished off with a quiz on moles skills.