Answer to Question #234604 in General Chemistry for Puppy

Question

A student begins preparing the Fe2+ stock solution by weighing 0.1756 g of (NH4)2Fe(SO4)2∙6H2O. The
solid is dissolved in a small amount of deionized water then transferred to a 250 mL volumetric flask.
The solution is brought to a volume of 250.0 mL with deionized water and mixed. The molar mass of
(NH4)2Fe(SO4)2∙6H2O is 392.15 g/mol.
a. Calculate the molarity of (NH4)2Fe(SO4)2∙6H2O in this stock solution.
b. Calculate the molarity of Fe2+ in this stock solution.
c. Calculate the concentration of Fe2+ in the stock solution in units of g/L.
d. Calculate the concentration of Fe2+ in the stock solution in units of μg/dL.

Answer 1

Molar mass of (NH4)2Fe(SO4)2∙6H2O.  = 394.2 g/mol

0.1756/394.2 = 0.00045 mol

0.00045/0.25 = 0.0018g/mol