empirical formula is the simplest ratio of whole numbers of components making up a compound
When iron reacts with sulfur it forms a compound containing both Fe and S.
during a reaction due to law of conservation of mass ,masses of reactants is equal to the masses of the products.
Since number of moles = mass/ molar mass
and both mass and molar mass is constant the number of moles of Fe and S too remain constant.
number of Fe moles reacted = 2.62 g / 56 g/mol = 0.0468 mol
number of S moles reacted = 1.50 g / 32 g/mol = 0.0469 mol
the molar ratio of Fe : S = 0.0468:0.0469
its almost similar to 1:1
this means that ratio of Fe to S is 1:1 in the compound
therefore empirical formula = FeS