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Standard enthalpy of formation needed for EDTA metal complexes

  1. Aug 12, 2014 #1

    I am trying to solve the chemical equilibria in a kraft mill bleach plant to predict mineral scale deposits. I am using the van't Hoff equation to account for temperature dependence of the formation constants, but I need the enthalpy of reaction for all equilibria and I am missing some data.

    What I am missing is data for EDTA complexes with Na+ and K+. I have the std enthalpy of formation for EDTA, Na+ and K+ but in order to get the enthalpy of reaction I also need EDTA-Na and EDTA-K.

    Does anyone know where I can find these values?

    Kind regards

  2. jcsd
  3. Aug 12, 2014 #2


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    Staff: Mentor

    Formation constants for EDTANa and EDTAK are quite small from what I remember - are you sure they play any important role in the system?
  4. Aug 12, 2014 #3
    I just automatically included all the ions of significant concentration. But you are right, the formation constants of Na and K are very low in comparison to other metals such as Ca and Mg - and they can probably be neglected. I'll try this and see how it works out.

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