Iron determination.
0.1604 g of a substance is dissolved in 100.0 ml of water. Of this solution 10.00 ml is diluted with water in a volumetric flask of 500 ml. By atomic absorption is found that the final solution contains 4.47 mg iron per liter. Calculate the molar mass of the substance, based on iron analysis.

Question

Iron determination. 
0.1604 g of a substance is dissolved in 100.0 ml of water. Of this solution 10.00 ml is diluted with water in a volumetric flask of 500 ml. By atomic absorption is found that the final solution contains 4.47 mg iron per liter. Calculate the molar mass of the substance, based on iron analysis.

aaronq · Answer

Find the molarity of iron in the original substance (take into account the dilution), use it to find the amount of moles of iron present, then the mass.

Use the percent composition (which is equal to the mass) to find the total molar mass of the compound.

$m_{Fe}=\dfrac{M_{Fe}}{M_T}*0.1604~g$

anonymous · Answer

I don't understand how 4,47 mg can be translated to a concentration of 4,47*10^-3 M?

aaronq · Answer

yeah, thats it.  are you sure it's "$mg$" and not "$\mu g$"?