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1.) Determine the mass of ferrous ammonium sulfate hexahydrate, Fe(NH4)2(SO4)2 (

ID: 633209 • Letter: 1

Question

1.) Determine the mass of ferrous ammonium sulfate hexahydrate, Fe(NH4)2(SO4)2 (times) 6 H2O, required to make 250.00 mL of a 1.20 X 10^-3 M solution of Fe^+2. The molar mass of the hydrated salt is 392.13 g/mole. PLEASE SHOW YOUR WORK FOR ALL THE QUESTIONS.

2.) What is the purpose of adding the hydroxylamine to your iron solutions?

3.) Balance the following equation in acidic solution: NH2OH(aq) + Fe^+3 (aq) ------> N2(g) + Fe^+2(aq)

a.) Oxidation half-reaction:

b.) Reduction half-reaction:

c.) overall balanced reaction:

4.) For the chemical equation given in problem #3 identify the oxidizing and reducing agents.

a.) Oxidizing agent = _____________          b.) Reducing agent = ________________

Explanation / Answer


mmol of salt solution =250*0.0012 =0.3 mmol = mmol of hydrated salt.

molecular mass of hydrated salt =392.13 g/mol


massof ferrous ammonium sulfate hexahydrate =moles *molecular mass

=392.13*0.3 =117.639 g


Hydroxylamine acts as an reducing agent in reduction of NH2OH to N2.


balanced reaction : 2NH2OH(aq) + Fe^+3 (aq) ------> N2(g) + Fe^+2(aq) +2H2O + 2H+


reduction half :Fe^+3 (aq) + 1e- - -----> Fe^+2(aq)

oxidation half : 2NH2OH(aq) - 2e- ------> N2(g)

overall reaction : 2Fe^+3 (aq) +2NH2OH(aq)- - -----> 2 Fe^+2(aq) +N2(g)


reduing agent =NH2OH

oxidising agent =Fe3+