TN1:

Đặt `n_{MgO}=x(mol);n_{FeO}=y(mol);n_{Fe_2O_3}=z(mol)`

`->40x+72y+160z=13,92(1)`

`520mL=0,52L`

`n_{HCl}=0,52.1=0,52(mol)`

`MgO+2HCl->MgCl_2+H_2O`

`FeO+2HCl->FeCl_2+H_2O`

`Fe_2O_3+6HCl->2FeCl_3+3H_2O`

Theo PT: `n_{HCl}=2x+2y+6z=0,52(2)`

TN2:

Đặt `n_{MgO}=kx(mol);n_{FeO}=ky(mol);n_{Fe_2O_3}=kz(mol)`

`->kx+ky+kz=0,27(3)`

`FeO+H_2`  $\xrightarrow{t^o}$  `Fe+H_2O`

`Fe_2O_3+3H_2`  $\xrightarrow{t^o}$  `2Fe+3H_2O`

Theo PT: `n_{H_2O}=ky+3kz={4,86}/{18}=0,27(4)`

`{(3)}/{(4)}={x+y+z}/{y+3z}={0,27}/{0,27}=1`

`->x+y+z=y+3z`

`->x-2z=0(5)`

`(1)(2)(5)->x=0,08;y=0,06;z=0,04`

`->k={0,27}/{0,08+0,06+0,04}=1,5`

`->` TN2: `n_{MgO}=0,12(mol);n_{FeO}=0,09(mol);n_{Fe_2O_3}=0,06(mol)`

Theo PT: `n_{Fe}=n_{FeO}+2n_{Fe_2O_3}=0,21(mol)`

`->m=0,12.40+0,21.56=16,56(g)`