PTHH: Fe + 2HCl -> FeCl2 + H2
----------0,1----------------0,1----------
PTHH: FeCl2 + 2NaOH -> Fe(OH)2 +2 NaCl
-----------0,1-------------------------0,1-------------
PTHH: 4Fe(OH)2 + O2 + 2H2O -> 4Fe(OH)3
-------------0,1---------------------------------0,1---
PTHH: 2Fe(OH)3 -to-> Fe2O3 + 3H2O
------------0,1-----------------0,05-------
nFe2O3 = m/M = 8/160 = 0,05 (mol)
Từ PTHH => nFe = 0,1 (mol)
=> mFe = n.M = 56.0,1 = 5,6 (g)
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