Name_______________
Partner______________
Date__________
Chemistry 120 - Experiment #10
Analysis and uses of Potassium Tris(oxalate)ferrate (III)
Data and Results: Please show calculations at the end of this lab
Part I: Determination of the Purity of K3[Fe(ox)3] by titration
Note:
Use approximately 0.16 gram-samples, 4-decimal place accuracy
Molarity of KMnO4 solution _______________________________M
Table 1.
Trial
Mass
(grams)
Buret Readings (mL)
Initial Volume
Final Volume
Volume of KMnO4 to
sample mass ratio
(mL/g)
Volume KMnO4 used
1
2
3
Calculations: Perform the following calculations twice using two titration results that have similar
volume to mass ratio.
Molarity KMnO4 x Titer x 1.0 mol complex
1.2 mol KMnO4
Calculate % purity.
x 491.15 grams/mol = grams K3[Fe(ox)3] •3H2O
% Purity = Sum of the two K3[Fe(ox)3]•3H2O masses calculated x 100%
Sum of two sample masses used
Part II: Use of K3[Fe{ox)3]•3H2O as an actinometer.
Absorbance of the actinometer solution at 512 nm = __________________________
Calculations:
A= εbC [Where ε = 7.0 x 103 M-1 •cm-1) and b = 1.0 cm.
Therefore, C= A/εb = moles of Fe2+ per liter = moles of photons per liter
Now, moles of photons/L x 0.0500L ÷ total # seconds = mol of photons absorbed per second.
Please do calculations on separate page. 1) ratio mg/L 2) avg best two 3) grams of product calc.
4) % purity 5) mole of photon absorbed per sec.
6) Explain why the ratio is 1.0 mol complex : 1.2 mole KMnO4 (give calc or words).