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?

1 Answer
Sep 23, 2016

Answer:

Approx. #100*g#.

Explanation:

We need (i) a stoichiometric equation:

#S(s) + 3F_2(g) rarr SF_6(g)#.

And (ii) the molar equivalence of sulfur and fluorine #=#

#(28.6*g)/(32.06*g*mol^-1)# #=# #0.892*mol#.

And thus #0.892xx3xx38.00*g*mol^-1# #~=# #100*g# fluorine gas are required.

Just a note on the molecularity of sulfur, of course I could have treated it as #S_8# as you did. The arithmetic is a bit easier if I give the equation as written above: 3 equiv of fluorine gas react with 1 equiv of sulfur. Note that fluorine, like all the other elemental gases (SAVE FOR THE NOBLE GASES), is binuclear, i.e. a diatomic molecule.