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Someone asked about what we covered in ch 13 so far and<br>
what you're responsible for, particularly from section 13.1.<br>
<br>
<big><font size="2"><big><big><font size="2"><big>We completed
sections 13.1-13.4 and started 13.5.<br>
We will complete ch 13 this coming Thur and start ch 14.<br>
<br>
</big></font></big>Look at the "Notes" link for details
about what we aren't covering<br>
in the various sections. In section 13.1 you essentially need
to<br>
cover the subsection about "The Effect of Intermolecular
Forces<br>
on Soln. Formation", Figures 13.2 and 13.3 and the end of this<br>
section about solubility due to reactions and hydrates (and
Fig 13.6).<br>
<br>
In the first half of the notes, pages 1-29, I skipped pages
21-29.<br>
Those pages correspond to the material in section 13.1 which<br>
we are largely skipping. I did discuss a few things from this<br>
section you should know (pages 14-20). I mentioned entropy<br>
in lecture, explained what it was and how it helps solutions
form<br>
but we'll cover it in more detail in ch 19. We talked about
how<br>
intermolecular att. forces affect solution formation (also
discussed<br>
in section 13.3 in the book). I discussed energetics of
solution<br>
formation in some detail for an ideal solution formation
(H_soln = 0).<br>
I mentioned endothermic and exothermic solution formation but<br>
we didn't discuss this in detail. In class I referred to the
third<br>
step as H_solvation (solute and solvent interactions). The
newer<br>
editions of the book (12th-14th) refer to this step as H_mix.<br>
<br>
I would suggest you read all of section 13.1 because it can
help<br>
with some other things in subsequent sections. However, I
won't<br>
ask direct questions from the parts of 13.1 I've stated as not<br>
being covered on the next midterm.<br>
<br>
Finally, in section 13.1 the book discusses solution formation
due<br>
to chemical reactions. I did mention this but it is different
than<br>
the solution process we are normally referring to, considered
a<br>
physical process rather than a chemical process. Diamonds
don't<br>
dissolve in just about any solvent. However, they will
dissolve in<br>
nitric acid because the nitric acid oxidizes the carbon and
the<br>
product is what dissolves. When you allow the solvent (H2O in<br>
this case) to evaporate you aren't getting the diamond back.<br>
This is similar to a metal dissolving in acid. That process
is due to<br>
a chemical reaction between the metal and the acid to
generally<br>
produce a soluble ionic compound. Again, when the solvent<br>
evaporates you don't get the metal but instead you get the
ionic<br>
compound. This is all discussed in the last part of section
13.1.<br>
<br>
We will complete 13.5 and 13.6 today. Section 13.6 has been<br>
posted as videos.<br>
<br>
Dr. Zellmer</big></font></big>
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