Answer:
MgBr₂
Explanation:
Here we need to find the molar proportions of the two elements which will give us the empirical formula of the compound. To do that,we need to determine the number of moles the grams given represent, and then convert them to whole numbers to find their proportions.
Atomic weght Br = 79.904 g/mol mol
⇒ mol Br = 32.0 g/ 79.904 g/mol = 0.40 mol
Atomic weight Mg = 24.305 g/mol
⇒ mol Mg = 4.9 g/24.305 g/mol = 0.20 mol
Their proportions are
0.40 Br ÷ 0.20 Mg = 2 Br ÷ 1 Mg
Empirical formula = MgBr₂