Hey there!:
Number of moles of iron:
Molar mass iron: 55.85 g/mol
0.676 / 55.85 => 0.012 moles of iron
Number of moles of fluorine:
Molar mass fluorine : 19 g/mol
0.460 / 19 => 0.024 moles of fluorine
Number of moles of water:
Molar mass water : 18.02 g/mol
0.870 / 18.02 => 0.048 moles of water
Simplest mol ratio is :
iron ( Fe ) = 0.012 / 0.012 => 1.0 mol
Florine ( F ) = 0.024 / 0.012 => 2.0 moles
Water ( H2O ) = 0.048 / 0.012 => 4 moles
Therefore:
Empirical formula is:
FeF2.4H2O
Hope that helps!
