Hỗn hợp $X$ gồm $MgO$ ($x$ mol), $FeO$ ($y$ mol), $Fe_2O_3$ ($z$ mol). Quy đổi $Fe_3O_4=FeO.Fe_2O_3$.
$\Rightarrow 40x+72y+160z=5,92$ $(1)$
Bảo toàn $Mg$: $n_{Mg}=n_{MgO}=x (mol)$
Bảo toàn $Fe$: $n_{Fe}=n_{FeO}+2n_{Fe_2O_3}=y+2z (mol)$
$\Rightarrow 24x+56(y+2z)=4,16$ $(2)$
Sau các phản ứng, $6g$ rắn gồm:
$MgO$: $x$ mol
$Fe_2O_3$: $0,5y+z$ mol
$\Rightarrow 40x+160(0,5y+z)=6$ $(3)$
$(1)(2)(3)\Rightarrow x=y=0,01; z=0,03$
Y gồm $MgCl_2$ ($0,01$ mol), $FeCl_2$ ($0,01$ mol), $FeCl_3$ ($0,06$ mol)
$n_{AgCl}=2n_{MgCl_2}+2n_{FeCl_2}+3n_{FeCl_3}=0,22(mol)$
$n_{Ag}=n_{FeCl_2}=0,01(mol)$
$\to m=0,0.108+0,22.143,5=32,65g$
PTHH và PT ion thu gọn:
$2Mg+O_2\buildrel{{t^o}}\over\to 2MgO$
$3Fe+2O_2\buildrel{{t^o}}\over\to Fe_3O_4$
$4Fe+3O_2\buildrel{{t^o}}\over\to 2Fe_2O_3$
$2Fe+O_2\buildrel{{t^o}}\over\to 2FeO$
$MgO+2HCl\to MgCl_2+H_2O$
$\Rightarrow MgO+2H^+\to Mg^{2+}+H_2O$
$Fe_3O_4+8HCl\to 2FeCl_3+FeCl_2+4H_2O$
$\Rightarrow Fe_3O_4+8H^+\to 2Fe^{3+}+Fe^{2+}+4H_2O$
$Fe_2O_3+6HCl\to 2FeCl_3+3H_2O$
$\Rightarrow Fe_2O_3+6H^+\to 2Fe^{3+}+3H_2O$
$FeO+2HCl\to FeCl_2+H_2O$
$\Rightarrow FeO+2H^+\to Fe^{2+}+H_2O$
$MgCl_2+2NaOH\to Mg(OH)_2+2NaCl$
$\Rightarrow Mg^{2+}+2OH^-\to Mg(OH)_2$
$FeCl_2+2NaOH\to Fe(OH)_2+2NaCl$
$\Rightarrow Fe^{2+}+2OH^-\to Fe(OH)_2$
$FeCl_3+3NaOH\to Fe(OH)_3+3NaCl$
$\Rightarrow Fe^{3+}+3OH^-\to Fe(OH)_3$
$Mg(OH)_2\buildrel{{t^o}}\over\to MgO+H_2O$
$2Fe(OH)_2+0,5O_2\buildrel{{t^o}}\over\to Fe_2O_3+2H_2O$
$2Fe(OH)_3\buildrel{{t^o}}\over\to Fe_2O_3+3H_2O$
$MgCl_2+2AgNO_3\to Mg(NO_3)_2+2AgCl$
$\Rightarrow Ag^++Cl^-\to AgCl$
$FeCl_2+3AgNO_3\to Fe(NO_3)_3+2AgCl+Ag$
$\Rightarrow Fe^{2+}+3Ag^++2Cl^-\to Fe^{3+}+2AgCl+Ag$
$FeCl_3+3AgNO_3\to Fe(NO_3)_3+3AgCl$
$\Rightarrow Ag^++Cl^-\to AgCl$
