Memorandum

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

From:     Robley Light

Date:     March 11, 1996

Re:       Recitation 10, week of March 11


     Hand back tests and go over them.

     New material includes writing Lewis Dot structures,
electronegativity, formal charge and bond energies.  

     I'd suggest you do a couple of simple Lewis structures (CO2,
CH2O), a couple with resonance structures (CO3-2, NO2-1)  and do
some formal charge calculations (the above structures, plus SO3 and
ClO3-1).  Point out that octet rule in 3rd period elements can be
violated in order to reduce formal charge.

     Try to get at least one example in of calculating þH of
reaction from bond energies:

     þH = sum of bonds broken - sum of bonds formed.