Elemental sulfur occurs as octatomie molecules, #S_8#. What mass of fluorine gas is needed to react completely with 28.6 g of sulfur to form sulfar hexafluoride?
We need (i) a stoichiometric equation:
And (ii) the molar equivalence of sulfur and fluorine
Just a note on the molecularity of sulfur, of course I could have treated it as