What is the empirical formula for a substance that contains 24.59% phosphorus and 75.41% fluorine by mass?

In order to obtain the empirical formula, first divide each element by its molar mass which can be found in the periodic table. The answer in the first step would be the number of moles of each element. Then divide each element with the lowest number of moles obtained in the first step in this case Phosphorus had the lowest number of moles. Then round it up to the nearest whole number. The empirical formula then is Phosphorus pentafluoride or PF5.