Memorandum

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

From:     Robley Light

Date:     February 12, 1996

Re:       Recitation 6, week of February 12


     Attached is a key to the hour tests in both sections, in case
you have students attending from both, as well as an overhead
showing the grade distribution in each class.  

     Grades were poorer than I had hoped, probably due in part to
the length.  Students who were more than 10 points below the median
should be worried, though.  I doubt that the length made much more
than 5-8 points difference.  Those who are seriously working hard
and had a bad result should not give up, since the final exam can
replace a low test grade.

     You will probably spend a good part of the recitation time
going over the exam.  These are all rather simple, straightforward
problems, and everyone should be clear on how they should have been
worked.

     We started on chapter 5 in class.  I talked a little generally
about the concept of energy, discussed the first law, and I spent
a little time today making the distinction between þE and þH, which
is not something I will test them on.  I did a simple calculation
involving specific heat today and plan to do a couple more on
Wednesday.  Then I want to get into calorimetry as a measurement of
heat change, where there is a subtle difference in that the
calorimeter constant is in J/degree (implied J-degree-1-
calorimeter-1), whereas if one is given a quantity of water in a
calorimeter, then one uses the specific heat in J-deg-1-g-1.

     You might try to do at least one calorimetry problem where þH
of a reaction is measured (such as problems 5.35-5.38), emphasizing
that when þH of a reaction is reported, it is per mole of reactant
(and might require fractional coefficients for other reactants and
products).  If time permits, introduce Hess's Law.