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Homework Help: Mass percent of Fe

  1. Sep 5, 2013 #1
    An iron ore sample weighing 0.9292g is dissolved in HCl(aq), and the iron is obtained as Fe2+(aq). This solution is then titrated with 30.86mL of 5.027×10−2M K2Cr2O7(aq).


    So how would i go about finding the mass percent of Fe in the ore sample?

    I tried multiplying 30.86ml with the 5.027×10−2M K2Cr2O7(aq) to find the mol of K2Cr2O7 but I have no idea what i am doing with that..Please respond as soon as you can!! thanks
  2. jcsd
  3. Sep 6, 2013 #2
    Can you format things a bit nicer, makes it easier to read.

    Anyway, your equation is 6Fe2+ + 14H+ + Cr2O72- → 6Fe3+ + 2Cr3+ +7H2O

    If you have the amount of dichromate from your titration, what does the balanced equation tell you?
  4. Sep 6, 2013 #3
    The units of molarity are moles/liter. How many liters are there in 30.86 ml? How many moles of dichromate were consumed in the titration? How many moles of iron are oxidized per mole of dichromate titrated? How many moles of iron were in the solution? How many grams of iron were there in the solution?
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