A compound contains 36.76% FE, 21.11 %S, AND 42.13% O BY MASS. WHAT IS THE EMPIRICAL FORMULA OF THE COMPOUND?

Answer 1

The atomic masses are:
Fe: 55.845 = F; S: 32.065 = S; and O: 15.999 = O.
Let T = 36.76%/F + 21.11%/S + 42.13%/O.

36.76% FE, 21.11% S, and 42.13% O BY MASS <==>
36.76%/FT = 16.67% Fe, 21.11%/ST = 16.67% S, and 42.13%/OT = 66.67% O by Mole <==> 1-portion of Fe, 1-portion of S, and 4-portion of O.

Therefore THE EMPIRICAL FORMULA OF THE COMPOUND is FeSO4.