Errors in Sections 17.1-17.3 - sample and practice exercises, Go Figure, Self-Assessment, etc.

[Zellmer, Robert]

There are some problems with several of the practice exercises that follow the
Sample Exercises in Ch 16.  The following also has corrections for sample
exercises, Go Figure questions and Self-Assessment exercise.

Section 17.2:

Practice Exercise 17.3:

I get pH 4.42.  The answer given is 4.50.

Practice Exercise 17.6:

I get 4.686 which rounds to 6.69.  The answer given is 6.68 so it's just a matter
of incorrect rounding or they rounded in intermediate steps.

Self-Assessment 17.4:

The answer given is 3.81.  It should be 2.81 (I get 2.83 solving a quadratic rather
than using the Henderson-Hasselbalch eqn).

Self-Assessment 17.6:

The answer given is 3.57.  That's the pH of the buffer before any HCl is added.
It should be 3.14 (I get 3.21 solving a quadratic rather than using the HH eqn,
about a 2.2% error).

Section 17.3:

Go Figure 17.9:

The answer given is "Aspirin.  It contains 9 carbon atom".  That doesn't answer the
question.    the answer should be " No, the amount of base needed to reach the
equivalence pt. would be the same".  "The pH would change.  For a strong
monoprotic acid- strong base titration the pH = 7".

Go Figure 17.15:

The answer has HPO3^z-.  It should be HPO3^-2.

Sample Exercise 17.10:

Part (a) gives the molar mass as 94.5 g/mol.  I get 90.9 g/mol.  This is closer to
the actual molar mass of butanoic acid with a molar mass or 88 g/mol, as given
in the answer for Part (c).


Dr. Zellmer











-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osu.edu/pipermail/cbc-chem1220/attachments/20230226/8d97bef9/attachment-0001.html>