Given the following data, determine the % by mass of Iron (III) (Fe3+) in a samp
ID: 505394 • Letter: G
Question
Given the following data, determine the % by mass of Iron (III) (Fe3+) in a sample of an iron oxalate complex with the general formula Kz[Fex(C2O4)y].wH2O.m(iron oxalate complex) used for stock sample = 0.0100 g
Vtotal (stock sample solution) = 25.00 mL
Valiquot (stock sample solution) = 1.00 mL
Vtotal (diluted sample solution) = 25.00 mL
Cdil(Fe3+) = 1.760 mg/L (from calibration curve)
Enter your answers in the boxes provided to 3 significant figures. Do not enter units.
Step 1: Given a concentration for your diluted sample solution, determine the concentration of Fe3+ in your stock sample solution:
C1 x V1 = C2 x V2
Cstock(Fe3+) = [Cdil(Fe3+) x Vtotal (diluted sample solution)] / Valiquot (stock sample solution)
= ____________ mg/L
Step 2: Determine the mass of Fe3+ in your stock sample solution:
m(mg) = C(mg/L) x V(L)
m(Fe3+) in stock sample solution = Cstock(Fe3+) x [Vtotal (stock sample solution)/1000]
= ________________ mg
Step 3: Determine the percentage mass of Fe3+ in your sample (don’t forget to convert all masses to g or mg)
%m(Fe3+) = [m(Fe3+) / m(iron oxalate complex)] x 100
= ________________ %
Given the following data, determine the % by mass of Iron (III) (Fe3+) in a sample of an iron oxalate complex with the general formula Kz[Fex(C2O4)y].wH2O.
m(iron oxalate complex) used for stock sample = 0.0100 g
Vtotal (stock sample solution) = 25.00 mL
Valiquot (stock sample solution) = 1.00 mL
Vtotal (diluted sample solution) = 25.00 mL
Cdil(Fe3+) = 1.760 mg/L (from calibration curve)
Enter your answers in the boxes provided to 3 significant figures. Do not enter units.
Step 1: Given a concentration for your diluted sample solution, determine the concentration of Fe3+ in your stock sample solution:
C1 x V1 = C2 x V2
Cstock(Fe3+) = [Cdil(Fe3+) x Vtotal (diluted sample solution)] / Valiquot (stock sample solution)
= ____________ mg/L
Step 2: Determine the mass of Fe3+ in your stock sample solution:
m(mg) = C(mg/L) x V(L)
m(Fe3+) in stock sample solution = Cstock(Fe3+) x [Vtotal (stock sample solution)/1000]
= ________________ mg
Step 3: Determine the percentage mass of Fe3+ in your sample (don’t forget to convert all masses to g or mg)
%m(Fe3+) = [m(Fe3+) / m(iron oxalate complex)] x 100
= ________________ %
Given the following data, determine the % by mass of Iron (III) (Fe3+) in a sample of an iron oxalate complex with the general formula Kz[Fex(C2O4)y].wH2O.
m(iron oxalate complex) used for stock sample = 0.0100 g
Vtotal (stock sample solution) = 25.00 mL
Valiquot (stock sample solution) = 1.00 mL
Vtotal (diluted sample solution) = 25.00 mL
Cdil(Fe3+) = 1.760 mg/L (from calibration curve)
Enter your answers in the boxes provided to 3 significant figures. Do not enter units.
Step 1: Given a concentration for your diluted sample solution, determine the concentration of Fe3+ in your stock sample solution:
C1 x V1 = C2 x V2
Cstock(Fe3+) = [Cdil(Fe3+) x Vtotal (diluted sample solution)] / Valiquot (stock sample solution)
= ____________ mg/L
Step 2: Determine the mass of Fe3+ in your stock sample solution:
m(mg) = C(mg/L) x V(L)
m(Fe3+) in stock sample solution = Cstock(Fe3+) x [Vtotal (stock sample solution)/1000]
= ________________ mg
Step 3: Determine the percentage mass of Fe3+ in your sample (don’t forget to convert all masses to g or mg)
%m(Fe3+) = [m(Fe3+) / m(iron oxalate complex)] x 100
= ________________ %
Explanation / Answer
Ans. Iron oxalate (Potassium ferrioxalate), K3[Fe(C2O4)3]·3H2O.
Molar mass of the complex = 1095.02758 g/ mol
#1. [Fe3+] stock = (C2 x V2)/ V1
= [(1.760 mg/ L) x 25.0 mL] / 1.0 mL
= 44.000 mg/ L
#2. Mass of Fe3+ = [Fe3+] stock x VTotal in liters
= (44.000 mg/ L) x (25/ 1000) L ; [1 L = 1000 mL]
= 1.100 mg
= 0.0011 g ; [1 g = 1000 mg]
#3. See the formula of complex, 1 mol complex consists of 1 mol Fe3+. Therefore, number of moles of the complex is equal to the number of mole of Fe3+.
Now,
Moles of Fe3+ = Mass/ Molar mass
= 0.0011g / (55.847 g/ mol) = 1.96966 x 10-5 mol
So, moles of iron oxalate complex = Moles of Fe3+ = 1.96966 x 10-5 mol
Mass of complex = Number of moles x Molar mass
= (1.96966 x 10-5 mol) x (1095.02758 g/ mol)
= 0.021568 g
% Fe3+ = (Mass of Fe3+ / Mass of complex) x 100
= (0.0011 g / 0.021568 g) x 100
= 5.100 %
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