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Homework Help: Chemistry Moles, Molecular Weight

  1. Sep 20, 2008 #1
    1. The problem statement, all variables and given/known data

    I did an experiment and found the weight of CaC(2)O(4)H(2)0 to be 31.4966 subtracted by the weight of a crucible which is 31.2612.

    I put this for my weight of CaC204H20 (as I can't think of any other weight that it would be requested). I followed the next question calculating molecular weight. 146.112. After that I calculated the moles of CaC204H20 to be 1.6 x 10^-3 (not sure on this).

    I now need the moles of Ca(2+ charge). There are 27.42% Ca(2+) mass percentage of it.

    I don't know what to do from there. Same goes for the concentration of Ca(2+)

    2. Relevant equations

    3. The attempt at a solution

    If I had to guess, I would say the moles of Ca2+ are 0.2742 times 146.112, but I am not sure.

    Concentration, I have no clue. I have been looking through my online notes on this for hours now. Thanks for any help.
  2. jcsd
  3. Sep 20, 2008 #2


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    2017 Award

    Your calculation of the moles of CaC2O4*H2O is correct. According to the formula of the compound, how many moles of Ca2+ does one mole of the compound contain?
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