What is the empirical formula of a mineral having the percent composition 28.59 O 24.95 Fe 46.46 Cr.?

O: 28.59 g x 1 mole O/16 g = 1.79 moles OFe: 24.95 g x 1 mole/55.8 g = 0.447 moles Fe

Cr: 46.46 g x 1 mole/52 g = 0.893 moles Cr

Dividing through by 0.447 one gets 4O, 1Fe and 2Cr

Empirical formula = FeCr2O4