Memorandum

To:       CHM 1045 Recitation Instructors
          Dillhyon, Martin, Callihan, Guile

From:     Robley Light

Date:     February 5, 1996

Re:       Recitation 5, week of February 5


     Attached is a key to the quizzes in both sections, in case you
have students attending from both.  

     The only new thing is calculating molarity and using molarity
to calculate moles, and calculating change in molarity on dilution. 
Then apply this calculation to a stoichiometry calculation.  I
suggest you might do a simple limiting reagent problem involving
mixing a given volume of HCl solution of known molarity with a
given volume of NaOH of known molarity, figuring out the limiting
and excess reagent, and calculating the amount of sodium chloride
produced and the amount of excess reagent left.  (I haven't gotten
to the problem of diprotic acids.  I may mention it Wednesday, but
I won't give a problem like that on the test as it may be unduly
confusing to them at this point.)

     I have pointed out that M means mol/L or mmol/mL, and one can
use either in problems.

     Copies of last falls tests were sent to the students by email
(purposively to stimulate their use of the internet).  We are
giving the test a week later this spring, so note that page one of
test 2 from last term is fair game. 

     I did not give out keys, but expect the students to try to
work the tests on their own, then get with their groups to argue
who is right.  However, it is fair game if they ask questions in
recitation about the old tests.

     So there is a lot to do.  Go over the quiz, touch on molarity,
review limiting reagents using solutions in the calculation, and
review anything else they ask about.

     Again, I'd like each of you to schedule at least one help
session.  Let me know when, so I can send out email (you can email
the students as well) and announce in class on Wednesday.