J.R. S. answered 02/26/18
Tutor
5.0
(110)
Ph.D. University Professor with 10+ years Tutoring Experience
Using a molar mass of 284.05 g/mole for Fe(NH4)2(SO4)2●6H2O
moles of Fe(NH4)2(SO4)2●6H2O = 0.1201 g x 1 mole/284.05 = 4.23x010-4 moles
moles of Fe = 4.23x01-4 moles since there is 1 mole of Fe per mole of Fe(NH4)2(SO4)2●6H2O
If I understand correctly, this was in 100 ml and then 2 ml diluted to 50 ml. If that is the case, then ...
4.23x10-4 mole/100 ml x 2 ml = 8.46x10-6 moles
8.46x10-6 moles/0.05 L = 1.69x10-4 mole/L = 1.69x10-4 M = 0.000169 M