Chemistry 11:  Lab 4D was handed in at the start of today's class.  We had a discussion about dilutions and I showed how to make a 2X dilution, as well as a 5X and a 10X dilution.  We tried one calculation to determine the final concentration when water is added to a solution.  We read pages 99 - 102, then completed 78 - 82, 86 and 88.   We spent time finishing the practice test, which is due on Friday.  Moles Unit Test (Unit 5) on Monday.   In the second half everyone was given a unique solution to make using a concentrated stock solution.