Quiz 4 material

[robert zellmer]

Quiz 4:  Chapter 17 (17.1-17.3)

I apologize.  I forgot to send this.  I did say in class though the quiz 
would
cover up through titrations.  Thanks to one of your fellow students for
reminding me.

*Sections 17.1-17.2: *

Common-ion effect and buffer systems. Know what is meant by a CI effect.
Buffer systems are just a special type of CI problem. You should be able to
recognize when you have a buffer system as compared to a "normal" CI 
problem.
Why? If it's a buffer system you can use the Henderson-Hasselbalch eqn. to
calculate the pH of a solution. Remember, to be a buffer you have to 
have some
of each member of a conjugate acid-base pair of a weak acid or weak base 
(e.g.
HF/F-, NH3/NH4+). To be a good buffer system the ratio of the base 
component
to the acid component (or vice versa) should be between 10 and 0.1. 
Also, the
conc. of each component should be relatively large, usually 0.001 M or 
larger.
This has to do with something called buffer capacity, how much strong 
acid or
base can be neutralized ("absorbed") by the buffer so the pH doesn't change
much.

*Section 17.3: *

Acid-base titrations.

*Homework coverage (you should be able to all problems in the given ranges):

*
For those of you using the 14th edition the quiz covers sections 17.1-17.3
and homework problems 17.1-17.7, 17.13-17.48, 17.83-17.96, 17.110-17.116
*
*For those of you using the 13th edition the quiz covers sections 17.1-17.3
and homework problems 17.1-17.7, 17.13-17.48, 17.83-17.97, 17.110-17.114

For those of you using the 12th edition the quiz covers sections 17.1-17.3,
and homework problems 17.1-17.7, 17.13-17.48, 17.81-17.95, 17.108-17.112

For those of you using the 11th edition the quiz covers sections 17.1-17.3,
and homework problems 17.1-17.7, 17.13-17.46, 17.75-17.90, 17.102-17.106

*For the on-line homework:*

Do ch 17 homework review problem set.  It is due by *8 AM tomorrow*. That
was pointed out in a previous e-mail.  Remember there are the DSM questions
(*due by 11:59 PM tonight, I've extended the due date*). Also, there are the
practice exercise #1 problems and tutorial for Ch 17 (neither of which 
are for credit).

On the quiz, if you need to use an ICE table, you must show the work and 
the
ICE table. When making any assumptions you should show that your 
assumptions
are okay (less than 5% error). If the percent error is greater than 5%, you
need to solve the resulting quadratic equation or use the method of 
successive
approximations (both shown in class and in the notes). You must show this
work. If you don't, you will not get full credit.

There are 5 links concerning acids and bases on my class web page. Go to 
the
"Helpful Tidbits" link and you will find them at the bottom. These came 
about
from answering e-mail questions from students over the years.


Dr. Zellmer
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