Answer
$SeBr_{4}$
Work Step by Step
Convert the mass of each constituent element into moles by dividing by its molar mass:
$1.443g\ Se\times\frac{1mol}{78.971g}=0.01827mol\ Se$
$5.841g\ Br\times\frac{1mol}{79.904g}=0.07310mol\ Br$
Formulas have whole number subscripts so divide all the amounts by the smallest and round if the number is really close. Then multiply by whatever factor makes them all a whole number or very close to a whole number.
$\frac{0.01827mol\ Se}{0.01827}=1$
$\frac{0.0731mol\ Br}{0.01827}=4$
So the empirical formula for this compound is:
$SeBr_{4}$
