# Calculations for Spectrophotometric Titration

Pages: 1 (267 words) Published: January 24, 2012
Calculations
Standard Copper Solution
6.242 g CuSO45H2O dissolved and diluted to mark in a 250.00 mL Erlenmeyer flask

(6.242 g Cu〖SO〗_4 5H_2 O)((1 mol Cu〖SO〗_4 5H_2 O)/(249.68 g Cu〖SO〗_4 5H_2 O))((1 mol 〖Cu〗^(2+))/(1 mol Cu〖SO〗_4 5H_2 O))= 0.025 mol 〖Cu〗^(2+) ions M of 〖Cu〗^(2+)= (0.025 mol 〖Cu〗^(2+))/(0.250 L)=0.10 M 〖Cu〗^(2+) ions

Standardization of EDTA
25 mL aliquot of standard Cu2+ solution reacts with 14.596 mL of EDTA solution

((0.10 mol 〖Cu〗^(2+))/L)((0.02500 L)/1)((1 mol EDTA)/(1 mol 〖Cu〗^(2+) ))= 0.0025 mol EDTA M of EDTA= (0.0025 mol EDTA)/0.014596L=0.1713 M EDTA

Cu2+ concentration in an unknown Cu(II) solution reported as ppm CuSO45H2O 25.00 mL unknown solution requires 0.1012 mL EDTA solution for a complete reaction

((0.1713 mol EDTA)/L)((0.0001012 L)/1)((1 mol 〖Cu〗^(2+))/(1 mol EDTA))= 0.000017335 mol 〖Cu〗^(2+) 0.000017335 mol 〖Cu〗^(2+) ((1 mol Cu〖SO〗_4 5H_2 O)/(1 mol 〖Cu〗^(2+) ))((249.68 g Cu〖SO〗_4 5H_2 O)/(1 mol Cu〖SO〗_4 5H_2 O))= 0.004328 g Cu〖SO〗_4 5H_2 O

ppm Cu〖SO〗_4 5H_2 O= (mg Cu〖SO〗_4 5H_2 O)/(L solution)=0.004328 g Cu〖SO〗_4 5H_2 O ((1000 mg Cu〖SO〗_4 5H_2 O)/(1.000 g Cu〖SO〗_4 5H_2 O))(1/(0.0250 L solution))=173.12 ppm Cu〖SO〗_4 5H_2 O