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$1/$
$4X+nO_2 \to 2X_2O_n$
$n_{X}=a(mol)$
$n_{X_2O_n}=0,5a(mol)$
$\frac{X.a}{0,5a(X.2+16.n)}=\frac{4,05}{7,65}$
$X=9n$
$n=3; X=27$
$\to Al$
2/$
$Zn+H_2SO_4 \to ZnSO_4+H_2$
$2Al+3H_2SO_4 \to Al_2(SO_4)_3 +3H_2$
$n_{H_2}=0,08(mol)$
$n_{Zn}=a(mol)$
$n_{Al}=b(mol)$
$m_{hh}=65a+27b=3,79(1)$
$n_{H_2}=a+1,5b=0,08(2)$
$(1)(2)$
$a=0,05; b=0,03$
$m_{Zn}=0,05.65=3,25(g)$
$m_{Al}=0,03.27=0,8(g)$