Chromite ore, one of the few sources for pure chromium metal, is a mixture of predominantly Fe and Cr oxides. A 7.10 g sample of chromite was mixed with sodium carbonate and heated in a high O2 environment to produce sodium chromate and insoluble iron oxide.
These were separated by dissolving the sodium chromate in water and filtering out the iron oxide. The chromate ions were then recovered by adding Al(NO3)3 to produce a stable aluminum chromate, Al2(CrO4)3, precipitate, which was filtered, dried, and weighed.
If 5.82 g of precipitate was produced, what is the mass percent of chromium oxide, Cr2O3, in the original sample of chromite ore?
(please use gravimetric factor formula, and steps explaining in detail.)
n = stoichiometric number of moles of analyte or known.
