Gọi x,y lần lượt là số mol Fe, Al trong hh (x,y >0)

PTHH: Fe + H2SO4 -> FeSO4 + H2

x________x__________x_____x(mol)

2Al + 3 H2SO4 -> Al2(SO4)3 + 3 H2

y____1,5y_________0,5y___1,5y(mol)

b) Ta có hpt:

\(\left\{{}\begin{matrix}56x+27x=11\\x+1,5y=\dfrac{8,96}{22,4}=0,4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,1=nFe\\y=0,2=nAl\end{matrix}\right.\)

=>mFe=0,1.56=5,6(g) ; mAl=0,2.27=5,4(g)

c) nH2SO4(tổng)=nH2=0,4(mol)

=> mH2SO4(tổng)=0,4.98=39,2(g)

=>mddH2SO4=(39,2.100)/24,5=160(g)

$Fe + H_2SO_4 \to FeSO_4 + H_2$
$n_{Fe} = n_{H_2} = \dfrac{3360}{1000.22,4} = 0,15(mol)$
$n_{SO_2} = \dfrac{4480}{22,4.1000} = 0,2(mol)$
Bảo toàn electron : 

$3n_{Fe} + 2n_{Cu} = 2n_{SO_2}$

Suy ra: $0,15.3 + 2n_{Cu} = 0,2.2 \Rightarrow n_{Cu} = -0,025<0$

(Sai đề)

a/nH2= 0,1(mol)

Fe + H2SO4 -> FeSO4 + H2

0,1_________________0,1(mol)

=> mFe=0,1.56=5,6(g)

=> %mFe= (5,6/12).100\(\approx\) 46,667%

=> %mCu \(\approx\) 100% - 46,667% \(\approx\) 53,333%

b) mCu= 12-5,6=6,4(g) -> nCu= 0,1(mol)

Cu + 2 H2SO4(đ) -to-> CuSO4 + SO2 + 2 H2O

0,1___0,2__________________0,1(mol)

V=V(SO2,đktc)=0,1.22,4=2,24(l)

mH2SO4(p.ứ)=0,2.98=19,6(g)

=> mH2SO4(bđ)= 19,6 x 100/90 \(\approx21,778\left(g\right)\)

=> mddH2SO4 \(\approx\) (21,778 x 100)/98\(\approx22,222\left(g\right)\)

a, Ta có: 27n_Al + 56n_Fe = 0,83 (1)

PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

Theo PT: \(n_{H_2}=\dfrac{3}{2}n_{Al}+n_{Fe}=\dfrac{0,56}{22,4}=0,025\left(mol\right)\left(2\right)\)

Từ (1) và (2) \(\Rightarrow n_{Al}=n_{Fe}=0,01\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,01.27}{0,83}.100\%\approx32,53\%\\\%m_{Fe}\approx67,47\%\end{matrix}\right.\)

b, n_H2SO4 = n_H2 = 0,025 (mol)

\(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,025.98}{20\%}=12,25\left(g\right)\)

a.

 \(m_{Ag}=m_{k.tan}=8,7\left(g\right)\\ m_{Zn,Mg}=20-8,7=11,3\left(g\right)\\ \left\{{}\begin{matrix}n_{Zn}=a\left(mol\right)\\n_{Mg}=b\left(mol\right)\end{matrix}\right.\left(a,b>0\right)\\Zn+H_2SO_4\rightarrow ZnSO_4+H_2\\ Mg+H_2SO_4\rightarrow MgSO_4+H_2\\ \rightarrow\left\{{}\begin{matrix}65a+24b=11,3\\a+b=0,3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,2\end{matrix}\right.\)

\(\left\{{}\begin{matrix}\%m_{Ag}=\dfrac{8,7}{20}.100=43,5\%\\\%m_{Mg}=\dfrac{24.0,2}{20}.100=24\%\\\%m_{Zn}=\dfrac{0,1.65}{20}.100=32,5\%\end{matrix}\right.\)

b. 

\(n_{H_2SO_4\left(tổng\right)}=a+b=0,3\left(mol\right)\\ V_{ddH_2SO_4\left(tổng\right)}=\dfrac{0,3}{0,5}=0,6\left(lít\right)=600\left(ml\right)\)