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Homework Help: Hydrate problem

  1. Nov 12, 2007 #1
    hydrate problem :(

    1. The problem statement, all variables and given/known data

    When a hydrate of Na2CO3 . XH2O is heated until all of the water is removed, it loses 54.3 % of its mass. What is the value of X?

    2. Relevant equations

    3. The attempt at a solution
    such a bad attempt...

    Na2CO3=46g + 12g +48g=106g/mol

    106+18=124 x 0.543=67.33g

    I have no idea how to do this can someone please help me out
    Last edited: Nov 12, 2007
  2. jcsd
  3. Nov 12, 2007 #2


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    If 54.3% was water weight, that leaves 45.7% as the anhydride. This is like saying that for each 100 grams of hydrate dried, 54.3 grams was water and 45.7 grams was the anhydride. Can you take it from there?
  4. Nov 12, 2007 #3


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    The next step could be to find the number of moles of Na2CO3 and the number of moles of water; and then directly find mole ratio.
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