Question

Iron II reacs with 1,20 phenanthroline (phen) to form a stable complex ion under acidic conditions:Fe^+2 + 3 Phen---------?Fe(phen)3^+2The complex absorbs in the visible portion of the spectrum with wavelength max=510 nm. An ore sample containing 3.147% iron with mass of 1.0637 g was digested and diluted to a final volume of 1.00 L. The absorbance of this solution was measured at 510 nm using a 1.000 cm cuvette and had a value of A=0.6891 abs. An unknown sample with mass .2130 g was digested with the identical procedure and produced an abs of A=.2186 abs. Determine the percent iron in the unknown sample