REPORT SHEET EXPERIMENT Determination of the27 Solubility-Product Constant for a
ID: 582407 • Letter: R
Question
REPORT SHEET EXPERIMENT Determination of the27 Solubility-Product Constant for a Sparingly Soluble Salt A. Preparation of a Calibration Curve Initial [Cro, -DO z y m olume of 0.0024M K,COs 0.0024 M Kera Total voar nL Absorbance 0H Total volume 2yyll - Molar extinction coefficient for [CrO4 Average molar extinction coefficient Standard deviation (show calculations) B. Determination of the SoRrbility-Product Constant LAg l K of As Cro Absorbance 22 1.3292 -y 2. 3. 377 Copyright O 2015 Pearson Education, Inc.Explanation / Answer
A. Preparation of calibration a curve
molar extinction coefficient
1. (0.5 - 0.096)/(1.2 x 10^-4 - 2.4 x 10^-5) = 4208 M-1.cm-1
2. (0.995 - 0.5)/(2.4 x 10^-4 - 1.2 x 10^-4) = 4125 M-1.cm-1
3. (1.38 - 0.995)/(3.6 x 10^-4 - 2.4 x 10^-4) = 3208 M-1.cm-1
average molar extinction coefficient = 3847 M-1.cm-1
standrd deviation = sq,rt.[(average - individual)^2/3]
= sq.rt.[(130321 + 77284 + 408321)/3] = 453.11 M-1.cm-1
B. Determination of the solubility product constant
1. [Ag+] = 2 x 0.329/3847 = 1.71 x 10^-4 M
[C2O4^2-] = 8.55 x 10^-5 M
Ksp = [Ag+]^2.[C2O4^2-] = 2.50 x 10^-12
2. [Ag+] = 2 x 1.06/3847 = 5.51 x 10^-4 M
[C2O4^2-] = 2.75 x 10^-4 M
Ksp = 8.35 x 10^-11
3. [Ag+] = 2 x 1.1/3847 = 5.72 x 10^-4 M
[C2O4^2-] = 2.86 x 10^-4 M
Ksp = 9.36 x 10^-11
Average Ksp = 1.8 x 10^-10
standard deviation = sq.rt.[(individual-average)^2/3] = 2.2 x 10^-10
5. Qsp = [Ag+]^2/[C2O4^2-]
= (0.004 M x 0.005 L/0.010 L)^2.(0.0024 M x 0.005 L/0.010 L)
= 4.8 x 10^-9
Qsp > Ksp, so precipitation would occur
6. Ksp = 3.5 x 10^-11 (literature)
%error = (1.8 x 10^-10 - 3.5 x 10^-11) x 100/1.8 x 10^-10 = 80.55%
7. Ag2CrO4 is soluble in acidic (HNO3) mediumand it forms soluble AgNO3 and H2CrO4 in solution upon reaction
Ag2CrO4 + 2HNO3 <==> 2AgNO3 + H2CrO4
8. source of error is from incorrec titration value reading.
9. If th solution of KMnO4 was not prepared with accuracy, this would lead to error.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.