3. A sample of limestone weighing 1.2290 g was dissolved in acid. The iron isolated from the sample was reduced and the solution was transferred to a volumetric flask with a capacity of 100 cm3. To titrate 20.00 cm3 of the resulting solution, 10.52 cm3 of potassium dichromate solution with an iron titer of 0.003025 is consumed. What is the mass fraction of iron (III) oxide in the sample.

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