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Homework Help: Stoichiometry problem

  1. Jul 2, 2011 #1
    1. The problem statement, all variables and given/known data
    How many grams of potassium di chromate (K2Cr2O7) are present in 1 lit of its N/10 solution in acid medium?


    2. Relevant equations

    gram eq = NV = g/E = xg/M

    3. The attempt at a solution

    gram eq = NV = 0.1 * 1 = 0.1

    g = gram eq * mol wt / valence factor (The valence factor I have taken as 14 because there are 7 oxygen atoms in potassium dichromate, which means in acidic solution there would be 14 H+ atoms)

    0.1 * 294 / 14 = 2.1

    How to proceed beyond this? The answer is one of the four:4.9, 49, 0.49, 3.9.
     
  2. jcsd
  3. Jul 2, 2011 #2
    OK, got it.

    gram eq = no. of grams / Equ. wt

    E = mol. wt/val factor = 294.2 / 6 = 49

    g.e * E = 4.9.

    Is this the answer?
     
  4. Jul 2, 2011 #3

    Borek

    User Avatar

    Staff: Mentor

    Looks OK to me.
     
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