# Elemental sulfur occurs as octatomic molecules, #S_8#. What mass (g) of fluorine gas is needed to react completely with 17.8 grams of sulfur to form sulfur hexafluoride?

##### 1 Answer

Feb 21, 2016

#### Explanation:

**Start with a balanced equation.**

Then determine the molar masses of

**Determine the mass of #"F"_2"# needed to react completely with #"S"_8"# to form #"SF"_6"#.**

- Divide the given mass
#"S"_8"# by its molar mass. - Multiply the mole ratio between
#"F"_2"# and#"S"_8"# from the balanced equation with the moles#"F"_2"# in the numerator:#(24"mol F"_2)/(1"mol S"_8)# - Multiply moles
#"F"_2"# times its molar mass to get grams#"F"_2"# .