Determination of Solubility Product Constant Ksp
Purpose: To determine the solubility product constant for PbI2 (s).
Procedure: Watch the video, Determination of Solubility Product Constant.
Observations and Data
Write the Ksp equation and expression for PbI2
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A precipitate will form only if the Trial Ksp is _________________ than the Ksp value.
Table 1
Test Tube
Volume of
0.010M
Pb(NO3)3
Volume of
water(mL)
added
Volume of
0.020M KI
(mL)
Volume of
water (mL)
added
Precipitate
or no
precipitate
at room
temperature
Temperature
at which
precipitate
dissolves
(0C)
1
10.0
2
8.0
3
6.0
4
4.0
5
3.0
6
2.0
0.0
2.0
4.0
6.0
7.0
8.0
10.0
8.0
6.0
4.0
3.0
2.0
0.0
2.0
4.0
6.0
7.0
8.0
Questions
1. For each test tube 1-6 calculate the [Pb2+] in the final mixed solution. Use the
appropriate dilution factors; remember that the final volume in each case is the
sum of the volumes of both of the solution, total volume for test tube 1 is 20.0mL.
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2. Calculate the [I-] in the final mixed solution in each test tube.
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3. Calculate the value of the Trial Ksp for each test tube.
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4. Find the range of the values in which the experimental Ksp must lie. (This will be
between test tube 4, 5).
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4. Find the Ksp for each temperature and the solubility. The solubility is the same as
the [Pb2+]. Then make a graph of solubility (moles/litre) against temperature.
Test tube 1
Test tube 2
Temperature
Ksp
Solubility
5. What is the trend in solubility as temperature is increased?
Conclusion
State all your results and observations.
Test tube 3