Explore BrainMass

Explore BrainMass

    iron in sample

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    How many milligrams of iron are in the sample? See attached file for full problem description.

    © BrainMass Inc. brainmass.com October 9, 2019, 7:00 pm ad1c9bdddf


    Solution Preview

    First, we have to do is find the molar mass of ferrous ammonium sulfate hexahydrate in order to determine how much actual Fe is in the standard solution.

    I calculate it as 296.1 g/mol. Check this out yourself.

    Next, we need to find out what percentage the Fe is of the whole compound. Molar mass of Fe is 55.847 g/mol. Therefore,

    (55.847/296.1) x 100% = 18.86%

    Therefore, if we put in 70.2 mg (0.0702 g) of the compound, we have only 18.86% of that as Fe, right? That means we have:

    70.2 mg x 0.1886 = 13.24 mg Fe(II) in the 1 L flask.

    Therefore, the concentration of Fe(II) in that flask is:

    13.24 mg/1000 mL = 0.01324 mg/ml

    Now, we work through the dilutions.

    The 1st standard solution results from taking 1 mL of this stock solution and diluting to 100 mL. That's a 1:100 ...

    Solution Summary

    It finds the mass of iron in sample