1.     Sulfate can be determined indirectly by precipitating Ba SO₄ with excess Ba²⁺ and titrating the excess with EDTA.  A
        0.3260g sample containing sulfate is dissolved, and precipitated by adding 25.00mL of 0.03150 M BaCl₂.  After
        removal of the  Ba SO₄ by filtration, the excess Ba²⁺ was titrated with 26.38mL of 0.01822M EDTA.  Calculate the
        percentage of SO₄ in the sample.
 

2.    Calculate the value of pZn in the following solutions all at pH = 9.0, with a concentration of free NH₃ being 0.10M.
            a.    50mL of 0.010M Zn²⁺  +  20mL of 0.020M EDTA
            b.    50mL of 0.015M Zn²⁺  +  30mL of 0.025M EDTA
            c.    50mL of 0.025M Zn²⁺  +  50mL of 0.050M EDTA

3.    a.    Write autoprotolysis constant expressions for the following liquids:
                H₂O                1 x 10^-14
                C₂H₅OH         8 x 10^-20
                H₂SO₄            1.4 x 10^-4
                CH₃OH           2 x 10^-17
                NH₃                1 x 10^-33
                HCOOH         6 x 10^-7

        b.  Calculate pCation for each of the above solvents.
 
 

4.    In anhydrous methanol, the dissociation constant for acetic acid is 3.0  x  10^-10.  Calculate -logCH₃OH₂⁺ for a solution
        that is:
                a.    0.200M in acetic acid
                b.    0.100M in acetic acid and 0.200M in sodium acetate
                c.    0.200M in sodium acetate
 

5.     A 24 hour urine specimen was diluted to 2.000l.  After being buffered to pH 10, a 10.00mL aliquot was titrated with
        26.81mL of 0.003474M EDTA.  The calcium in a second 10.00mL aliquot was isolated as CaC₂O₄(s), redissolvedin
        acid, and titrated with 11.63mL of EDTA solution.  Assuming that 15 to 300mg of magnesium and 50 to 400mg of
        calcium per day are normal, did this specimen fall within these ranges?
 

6.    Calculate the conditional formation constants for EDTA complexes of the following:
        Mn²⁺  at:        a.  pH = 6.15            b.  pH = 8.43            c.  pH = 10.05
        Sr²⁺  at:          a.  pH= 7.6               b. pH = 9.45             c. pH = 11.1
 

7.    Create a graph that shows the influence of pH on the titration of 0.0100M Ca²⁺ with 0.0100M EDTA.
            Use pH = 6, 8, 10, 12
 

8.    Identify the oxidizing agent, reducing agent, and calculate the cell potential in the following reaction:

            Ce⁴⁺   +   Fe²⁺   <-->  Ce³⁺  +    Fe³⁺

        What type of cell would this be?
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This document was last modified on 12-Dec-00.