Mastering Chem Ch 13d(13.5, 13.6) Tutorials, #3

[Zellmer, Robert]

There's no problem with the question or the credit given.  The problem
lies in the explanation given in the problem when it discusses the
van't Hoff factor, "i".  It defines "i" a little differently than seen in the
book.  That's not the problem.  The problem is the associated paragraph.
It states "However, complete dissociation of electrolytes does not always
occur. The extent of dissociation is expressed by the van't Hoff factor, i:"

This is incorrect.  When an ionic compound dissolves, what ever amount
that does dissolves dissociates completely.  What occurs is ion pairs can
form, the hydrated ions attract each other and act as a single particle.
These are not molecules and don't stay together permanently.  The ions
are constantly forming ion pairs and ion pairs are constantly separating.
Then the ions go off and form an ion pair with another ion (of opposite
charge of course) and some ions stay as independent ions.  An equilibrium
occurs in which the number of ion pairs is constant, while the identity of
the individual ions in the ion pairs is always changing.  The number of
ion pairs which form depends on the concentration of solute and the
charges on the ions and their sizes.  See theCloser Look box about the
van't Hoff factor in Section 13.5.

Dr. Zellmer
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osu.edu/pipermail/cbc-chem1220/attachments/20230202/ce092680/attachment-0001.html>