Step-by-step explanation:
Fe= 55.8 F=18.9
FeF3 = 55.8 + (18.9×3)
= 55.8 + 56.7
= 112.5
Therefore 1 mole of FeF3 = 112.5g
If 1 mole = 112.5, the 15 moles = x
1 mole = 112.5g
x mole = 15g
~cross multiply~
x = 15 ÷ 112.5
x = 0.133 (recurring decimal)
Therefore, there are 0.133 moles in 15g of FeF3