A steel sample weighing 1.000 g is dissolved in acids andtreated with persulfate and periodate to oxidize Mn toMnO4- and Cr toCr2O7-. The solution is finallydiluted to 100.00 mL in a volumetric flask. An aliquot placed in a1.00-cm cuvette yielded an absorbance of 0.113 at 440 nm and of1.304 at 545 nm. The absorbance for a reagent blank was 0.005 at440 nm and 0.008 at 545 nm. Calculate the percentages (m/m) of Crand Mn in the steel. The molar absorptivity ofCr2O7- is 369M-1cm-1 at 440 nm and 11M-1cm-1 at 545 nm whereas that ofMnO4- is 95 M-1cm-1 at440 nm and 2350 M-1cm-1 at 545 nm. The molarmass of Mn is 54.94 g/mol and that of Cr is 52.00 g/mol.
