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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: custard_crem on September 04, 2020, 08:33:29 AM

Title: Finding Concentration of [Cu(EDTA)]^2- in Solution
Post by: custard_crem on September 04, 2020, 08:33:29 AM
Hi, I'm tabulating some results from a UV-vis spectrophotometer for university and a little unsure of one of the calculations.

I need to find the concentration (L-1 mol) of [Cu(EDTA)]2-. There were 0.15g of copper (II) acetate monohydrate and 0.4g of ethylenediaminetetraacetic acid dissolved in 0.1L of deionised water.

I've combined the moles/mass/Mr and concentration equations to give [itex]C = \frac {m}{(Mr × V)}[/itex]. My other calculations are fine but was wondering if on this one I would need to combine the masses and Mr both of copper (II) acetate monohydrate and ethylenediaminetetraacetic acid as it would be these two reacting together that would make the [Cu(EDTA)]2- complex? So would the equation for this one be:

C =  __(m(Cu(CO2CH3)2 ·H2O) + m(EDTA))___
      (Mr(Cu(CO2CH3)2 · H2O) + Mr(EDTA)) × V

(for some reason it's not liking my LaTeX code for the above fraction, even though it works on the LaTeX practice box so I hope you understand/ see the fraction)

Or would you just use the m and Mr of Cu(CO2CH3)2 · H2O because it's the limiting reagent?

Thanks
Title: Re: Finding Concentration of [Cu(EDTA)]^2- in Solution
Post by: Borek on September 04, 2020, 02:51:07 PM
Or would you just use the m and Mr of Cu(CO2CH3)2 · H2O because it's the limiting reagent?

Yes.