EXAM IV
CHM 333
Due 12-14 by 3:00pm.
This is not an open book exam, and you must complete this exam
on your own!
You are working in an Environmental Laboratory setting, and are just
beginning your career. You are eager to move up the ladder, and take every
opportunity to show your extensive Quantitative Analysis experience!
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a. You start by looking at an issue of titrating with EDTA. There is some
controversy over the level of interference when you are titrating Mg2+.
Use equation 13-11 on page 327 to compute the titration of 50mL 0.005M
Mg2+, Cd2+, and Fe2+ with 0.005M EDTA
at a fixed pH=10.
b. Now solve the issue of the change in titration with
a change in pH by showing the effect
of pH on the Mg2+
titration at pH= 5, 7, 8, 9, 12.
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a. For the first part of this portion you have two options; 1) You can
find a recent article which employs some type of titration, and explain
the titration scheme of the article, or
2) You can show the titration curve of pyrophosphoric acid (pKa's on pg.
AP30). You will need to define all concentrations (acid and base) and be
sure to use plenty of data points!
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Your bosses are really into rechargeable lightweight batteries, and ask
you to explain the following;
Zn(s) l ZnCl2(aq) ll Cl-(aq) l Cl2(l)
l C(s)
* l refers to a boundary
If the battery delivers a constant current of 1.00 x 103A
for 1.00 h, how many kilograms of Cl2 will be consumed?
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Describe how you might approach an unknown sample that might have arrived
at your lab, create a scenario that uses all of your Quantitative analysis
experience to solve the problem. You may define the analytes and properties
any way that is reasonable, just remember that you are trying to incorporate
all of your experience (including lab) into this scenario.
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This document was last modified on Wednesday, December 09 1998.