Ch 13 - notes and chapter coverage - clarification

[Zellmer, Robert]

Someone asked about what we covered in ch 13  so far and
what you're responsible for, particularly from section 13.1.

We completed sections 13.1-13.4 and started 13.5 last week.
We will complete ch 13 this coming Tue and start ch 14.

Look at the "Notes" link for details about what we aren't covering
in the various sections.  In section 13.1 you essentially need to
cover the subsection about "The Effect of Intermolecular Forces
on Soln. Formation", Figures 13.2 and 13.3 and the end of this
section about solubility due to reactions and hydrates (and Fig 13.6).

In the first half of the notes, pages 1-29, I skipped pages 21-29.
Those pages correspond to the material in section 13.1 which
we are largely skipping.  I did discuss a few things from this
section you should know (pages 14-20).   I mentioned entropy
in lecture, explained what it was and how it helps solutions form
but we'll cover it in more detail in ch 19.  We talked about how
intermolecular att. forces affect solution formation (also discussed
in section 13.3 in the book).  I discussed energetics of solution
formation in some detail for an ideal solution formation (H_soln = 0).
I mentioned endothermic and exothermic solution formation but
we didn't discuss this in detail.  In class I referred to the third
step as H_solvation (solute and solvent interactions).  The newer
editions of the book (12th-14th) refer to this step as H_mix.

I would suggest you read all of section 13.1 because it can help
with some other things in subsequent sections.  However, I won't
ask direct questions from the parts of 13.1 I've stated as not
being covered on the next midterm.

Finally, in section 13.1 the book discusses solution formation due
to chemical reactions.  I may have mentioned this but it is different
than the solution process we are normally referring, considered a
physical process rather than a chemical process.  Diamonds don't
dissolve in just about any solvent.  However, they will dissolve in
nitric acid because the nitric acid oxidizes the carbon and the
product is what dissolves.  When you allow the solvent (H2O in
this case) to evaporate you aren't getting the diamond back.
This is similar to a metal dissolving in acid.  That process is due to
a chemical reaction between the metal and the acid to generally
produce a soluble ionic compound.  Again, when the solvent
evaporates you don't get the metal but instead you get the ionic
compound.  This is all discussed in the last part of section 13.1.

Dr. Zellmer
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