[Solubility Product Constant]
Experiment 11

Molly McCabe
4/18/2013

Data Tables:
Part 1 and Part 2 Experimental Data:
Standard Calculated volume of copper sulfate in standards Absorbance values Blank 0.0 mL 0.0
1 1.25 mL 0.094
2 3.75 mL 0.065
3 2.50 mL 0.099
4 3.50 mL 0.129
5 5.00 mL 0.187
Collected Data Test tube 1 Test tube 2 Test tube 3 Test tube 4 Test Tube 5 Initial volume (mL) 0.05 0.10 0.0 0.0 0.0
Final volume (mL)  24.25 22.10 25.0 23.70 19.90 Total volume (mL)  24.20 22.0 25.0 23.70 19.90
Molarity S2O3 0.02519 M 0.02519 M 0.02519 M 0.02519 M 0.02519 M [IO3] 0.0254 M 0.0231 M 0.0285 M 0.0249 M 0.0209 M [Cu2+] 1.66 x 102 M 1.61 x 102 M 1.76 x 102 M 2.38 x 102 M 3.58 x 102 M Ksp 1.07 x 105 8.59 x 106 1.43 x 105 1.48 x 105 7.48 x 104
Class Data
Group Trial 1 (Ksp) Trial 2 Trial 3 Trial 4 Trial 5 Molly and Brooke 1.07 x 105 8.59 x 106 1.43 x 105 1.48 x 105 7.48 x 104 Casey and Marissa 4.60 x 106 8.00 x 106 9.24 x 106 2.66 x 105 1.59 x 105 Giang and Kristen 1.11 x 105 1.32 x 105 1.56 x 105 1.37 x 105 1.81 x 105 Alicia and Dan 6.01 x 106 5.75 x 106 1.92 x 106 1.12 x 105 1.48 x 105
Calculated Data
Group Average Ksp Standard Deviation Percent Error
Molly and Brooke 1.59 x 104 ± 3.29 x 104 113471.4% Casey and Marissa 1.30 x 105 ± 8.80 x 106 9185.7% Giang and Kristen 1.43 x 105 ± 2.64 x 106 10114.3% Alicia and Dan 7.94 x 106 ± 5.06 x 106 5571.4%
Uncertainties:
10 mL volumetric flask ± 0.02
25 mL volumetric flask ± 0.03
1 mL volumetric pipet ± 0.006
5 mL volumetric pipet ± 0.01
4 mL volumetric pipet ± 0.015
3 mL volumetric pipet ± 0.010
50 mL graduated cylinder ± 0.25
Buret ± 0.05
Colorimeter ± 0.0001
Analytical balance ± 0.0001
Sample Calculations:
1. Standard solutions: M1V1 = M2V2
* Test tubes 1 and 2: 25 mL
* Test tubes 35: 10 mL
* M)(25 mL) = x(0.200 M), x = 1.25 mL
2. Total volume: final – initial = total
25 mL – 0.0 mL = 25 mL
3. [IO3]: mol S2O31 LL of S2O31 mol I32 mol S2O31 mol IO33 mol I31 0.004 L = [IO3]
0.02519 mol S2O31 L0.022 L S2O31 mol I32 mol S2O31 mol IO33 mol I31 0.004 L = 0.0254 M
4. [Cu2+]: * use y = mx + b equation from graph: Abs = m[Cu2+] + b * Plug in Abs. values: [Cu2+] = Abs. bm
[Cu2+] = 0.0940.013534.850 = 1.66 x 102 M
5. Ksp = [Cu2+][IO3]
[1.66 x 102][0.0254] = 1.07 x 105
6. Average Ksp: (Ksp trial 1 + Ksp trial 2 + Ksp trial 3 + Ksp trial 4 + Ksp trial 5) / 5 = Avg. * 105 + 8.59 x 106 + 1.43 x 105 + 1.48 x 105 + 7.48 x 104) / 5 = 1.59 x 104
7. Standard Deviation: Xavg. Xn2n1
(1.59x1041.07x105)2+(1.59x1048.59x106)2+(1.59x1041.43x105)2+(1.59x1041.48x105)2+(1.59x1047.48x104)2(4) 8. Percent Error: acceptedtheoretical accepted x 100
1.4x107(1.59x104)(1.4x107) x 100= 113471.4%
Discussion:
The objective of this experiment was to measure the solubilityproduct constant of a soluble salt. The solubilityproduct constant, represented as Ksp, states that for equilibrium to exist between a solid substance and its solution, the solution must be saturated and in contact with an undissolved solid. Ksp is therefore measuring the solubility of the solid that has relatively low solubility. The higher the solubilityproduct constant, the more soluble the solid present in solution. To measure the Ksp values, colorimetry and titration techniques were used.
The experiment was divided into two parts; part 1 involved using the colorimeter to find the concentration of the Cu2+ and part 2 used titration to find the concentration of IO3. When both concentrations were found,...