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EDTA – An Introduction. CHM 103 Sinex. EDTA is e thylene d iamine t etra a cetic aicd. Six binding sites 4 H on carboxylic acid groups (H’s are removed, so –COO - ) 2 lone pairs of electrons on nitrogens. EDTA Chime structure.
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EDTA – An Introduction CHM 103 Sinex
EDTA is ethylenediaminetetraacetic aicd Six binding sites 4 H on carboxylic acid groups (H’s are removed, so –COO-) 2 lone pairs of electrons on nitrogens EDTA Chime structure For more information on EDTA – see the MOTM for March 2004.
Fe+3 + EDTA-4 FeEDTA-1 1:1 metal ion to EDTA metal ion with octahedral geometry
chemistry • Ca+2 with EDTA – 1:1 • at equivalence point: moles Ca = moles EDTA • so to find moles: moles = M x VL • standard calcium solution from CaCO3 CaCO3(s) + 2HCl(aq) CaCl2(aq) + CO2(g) + H2O • indicator – MgIn- HIn-2 wine red sky blue After Ca+2 reacts with EDTA, EDTA complexes Mg+2 from indicator.
Tracking the metal ion - EDTA titration indicator
If a student masses out 0.5251 g calcium carbonate, dissolves it in HCl, and then places it into a 500.0 mL volumetric flask, what is the molarity of the calcium ion? 0.5251 g x 1 mole/100g = 5.251 x 10-3 moles Ca+2 5.251 x 10-3 moles Ca+2/0.5000L = 0.1050 M answer If 25.00 mL of the Ca+2 solution above requires 18.93 mL of EDTA to titrate, what is the molarity of the EDTA? MCa x VCa = MEDTA x VEDTA hint