From a weighed portion of 1.200 g of a sample containing potassium chromate (K2Cr2O7), a solution was prepared in a volumetric flask with a capacity of 100.0 ml. An excess of lead nitrate solution (Pb(NO3)2) was added to 25.00 ml of the resulting solution. The resulting precipitate of lead chromate (PbCrO4) was filtered, washed, transferred to a solution, and treated with 10.00 ml of a 0.1000 M EDTA solution. The EDTA residue was titrated with 8.00 ml of a 0.05109M solution of zinc sulfate (ZnSO4). Calculate the mass fraction of chromate ions (CrO42-) in the sample.

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