Question

Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% oxygen by mass

Answer 1

Fe=69.9/55.8=1.25/1.25=1×2=2
O=30.1/16=1.88/1.25=1.5×2=3
here 55.8 and 16 are their atomic masses so empirical formula is Fe2O3..