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Weight %

  1. Oct 4, 2006 #1
    the equation is CaCl2 + 2AgNO3 --> AgCl Ca(NO2)2
    my mix is CaCl2 and other stuff that does not react with AgNO3.
    0.2918 g of mix gives 0.4462g of AgCl, what is the percent of CaCl2 in the mix?
    Molar masses are CaCL2 110.98g/mol and AgCl 143.32 g/mol.
    I am not sure if this is how to do it, however...
    moles of the AgCl is 0.4462/143.32 = 0.003113 mol

    moles of CaCl2 is 0.4462-0.2918 = 0.1544 grams of CaCl2, then 0.1544/110.98 = 0.001391 mols of CaCl2

    i don't know if that's right so far, or where to go from there. i know i need to use the ratios somewhere but ack!
    please help.
  2. jcsd
  3. Oct 4, 2006 #2
    the equation is CaCl2 + 2AgNO3 --> AgCl Ca(NO2)2

    Is this plus the calcium nitrite or a raised dot meaning its part of one unit?
    (AgCl Ca(NO2)2)?
  4. Oct 4, 2006 #3
    sorry, there should be a plus.

    CaCl2 + 2AgNO3 --> AgCl + Ca(NO2)2

    thanks for pointing it out!
  5. Oct 4, 2006 #4


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    Staff: Mentor

    Assuming you have correctly calculated that


    answer should be slightly over 50%...

    Trick is, 0.1544 is wrong. No idea what you are trying to find subtracting masses of different compounds. This is simple stoichiometric problem, easily solved using ratios (or dimensional analysis).
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