The empirical formula : FeBr₃
Further explanation
A 8.310 g sample of Iron, so mol of Iron(Ar=55.845 g/mol) :
![\tt mol=(mass)/(Ar)\\\\mol=(8.310)/(55.845)\\\\mol=0.149](https://img.qammunity.org/2021/formulas/chemistry/high-school/udopcqjoxs3z05r1ew4vya22njbgjyiwtr.png)
Mass of metal bromide formed : 43.98 g, so mass of Bromine :
![\tt =mass~metal~bromide-mass~Iron\\\\=43.98-8.310\\\\=35.67~g](https://img.qammunity.org/2021/formulas/chemistry/high-school/13nxqdbort0gct5efc9j1s8d2z6man82s4.png)
then mol Bromine (Ar=79,904 g/mol) :
![\tt (35.67)/(79,904)=0.446](https://img.qammunity.org/2021/formulas/chemistry/high-school/4suuxt1ti10xyag66tgrhw602flxzs34nu.png)
mol ratio of Iron and Bromine in the compound :
![\tt 0.149/ 0.446=1/ 3](https://img.qammunity.org/2021/formulas/chemistry/high-school/km5zziunauny6b0uzmbfi9d4o22lccycu4.png)