22: Experiment Solubility of a Slightly Soluble Electrolyte Jacob Roll 5/10/07 Wednesday Yaofang Zhang
PURPOSE For this experiment, the objective was to determine the solubility of the slightly soluble electrolyte Cu(IO3)2, copper(II) iodide, and also calculate the solubility product constant for the equilibrium. Before doing that, though, the molarity and volume of Na2S2O3 is needed to find the number of moles of S2O32- by doing the standardization of Na2S2O3. In Chemistry 103 lecture, thermodynamics and the molar solubility of certain solutions has been studied extensively, and is used in determining the spontaneity of a reaction. Two titrations were completed during this experiment using a buret to accurately record the volume of Na2S2O3. PROCEDURE The procedure followed for this experiment can be found in the lab manual: Sprague, Alexander, Padolik, Steffel, Experiments Laboratory for First Year Chemistry, 5th ed. pp. 22-2 to 22-3. Part A of the experiment was omitted because the solution had already been saturated. RESULTS The results for this experiment can be found on the report sheet included in this packet. DISCUSSION The results from this experiment are very satisfying. Though only two trials were needed in Part C, three trials had to be performed in Part B due to an error causing the first two trials to be very different, this may have been caused by an error in reading the volume on the buret, or by titrating the solution too much or too less. Besides that one
small error, the results for the next two trials in Part B were within 1% of each other, thus satisfying the objective. The two trials in Part C were very close and did not have any error in the calculations. QUESTIONS 1a)
1b)
1c)
2)