Answer:
1.78 moles
Explanation:
to find moles, use the formula moles=mass/rfm
the rfm is the mass number (the bigger number) on the element's square thingy on the periodic table
the mass number of fluorine is 19
19*2 (because it's diatomic you multiply it by 2) =38
so 67.8/38=1.78421052632
round it to 2 sf= 1.78 moles
