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Bruno
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Posts: 1
Joined: Tue Jul 05, 2022 9:13 am

I am struggling a lot with analytical chemistry and i really need help to solve this question.

A Cr3+ solution was prepared by dissolving 0.2525g of CrCl3.6H2O salt in 250 mL of 0.01 mol L-1 HCl. From this stock solution, a solution was prepared by diluting 21.3 mL of the stock solution in 50 mL of 0.01 mol L-1 HCl, adding a mass of EDTA sodium salt (Na2C10H12O8N2. 2H2O) necessary to the formation of the complex (calculate!). The solution was then heated to boiling temperature, changing colorless to violet, generating the Cr-EDTA complex. Thus: what is the concentration of free Cr3+ in solution, at equilibrium, after complexing with EDTA? Calculate the fraction of each of them. Then write the Cr3+ balance with each of these EDTA species present. Why was it necessary to warm up? The maximum absorption of the complex in the visible spectrum region occurs at 542nm. Calculate the energy per mole at this wavelength. Also calculate the electrostatic parameter of Cr3+, K of the EDTA-Cr complex = 2.51x10^23.
ChenBeier
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Location: Berlin, Germany