\(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)

\(m_{H_2SO_4}=\dfrac{10.196}{100}=19,6\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{19,6}{98}=0,2\left(mol\right)\)

PTHH:_______\(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\uparrow\)

Theo PT:mol:___1..........1..................1.............1

Theo ĐB:mol:___0,1.......0,2...............................

\(\Rightarrow H_2SO_4\)dư,Zn pứ hết

Theo PT: \(n_{H_2SO_4pư}=n_{ZnSO_4}=n_{Zn}=0,1\left(mol\right)\)

\(\Rightarrow n_{H_2SO_4dư}=0,2-0,1=0,1\left(mol\right)\)

\(\Rightarrow m_{H_2SO_4}=0,1.98=9,8;m_{ZnSO_4}=0,1.161=16,1\left(g\right)\)

\(\Rightarrow C\%_{H_2SO_4}=\dfrac{9,8}{196+6,5}.100\%\approx4,84\%\)

\(\Rightarrow C\%_{ZnSO_4}=\dfrac{16,1}{196+6,5}.100\%\approx7,95\%\)

\(n_{CuO}=\dfrac{3,2}{80}=0,04\left(mol\right)\)

\(n_{H_2SO_4}=\dfrac{100.20\%}{98}=0,204\left(mol\right)\)

PTHH:

\(CuO+H_2SO_4\rightarrow CuSO_4+H_2O\)

0,04      0,04           0,04    

\(\dfrac{0,04}{1}< \dfrac{0,204}{1}\) --> H2SO4 dư

\(C\%_{CuSO_4}=\dfrac{0,04.160}{3,2+100}.100\%=6,2\%\)

\(C\%_{H_2SO_4\left(dư\right)}=\dfrac{0,2.98}{3,2+100}.100\%=19\%\)

Câu 1:

CuO + H₂SO₄ → CuSO₄ + H₂O

\(n_{CuO}=\frac{3,2}{80}=0,04\left(mol\right)\)

\(m_{H_2SO_4}=200\times9,8\%=19,6\left(g\right)\)

\(\Rightarrow n_{H_2SO_4}=\frac{19,6}{98}=0,2\left(mol\right)\)

Theo PT: \(n_{CuO}=n_{H_2SO_4}\)

Theo bài: \(n_{CuO}=\frac{1}{5}n_{H_2SO_4}\)

Vì \(\frac{1}{5}< 1\) ⇒ H₂SO₄ dư

Dung dịch sau pư gồm: H₂SO₄ dư và CuSO₄

Ta có: \(m_{dd}saupư=3,2+200=203,2\left(g\right)\)

Theo Pt: \(n_{H_2SO_4}pư=n_{CuO}=0,04\left(mol\right)\)

\(\Rightarrow n_{H_2SO_4}dư=0,2-0,04=0,16\left(mol\right)\)

\(\Rightarrow m_{H_2SO_4}dư=0,16\times98=15,68\left(g\right)\)

\(\Rightarrow C\%_{H_2SO_4}dư=\frac{15,68}{203,2}\times100\%=7,72\%\)

Theo Pt: \(n_{CuSO_4}=n_{CuO}=0,04\left(mol\right)\)

\(\Rightarrow m_{CuSO_4}=0,04\times160=6,4\left(g\right)\)

\(\Rightarrow C\%_{CuSO_4}=\frac{6,4}{203,2}\times100\%=3,15\%\)

Câu 2:

ZnO + H₂SO₄ → ZnSO₄ + H₂O

\(n_{ZnO}=\frac{8,1}{81}=0,1\left(mol\right)\)

\(m_{H_2SO_4}=200\times24,5\%=49\left(g\right)\)

\(\Rightarrow n_{H_2SO_4}=\frac{49}{98}=0,5\left(mol\right)\)

Theo Pt: \(n_{ZnO}=n_{H_2SO_4}\)

Theo bài: \(n_{ZnO}=\frac{1}{5}n_{H_2SO_4}\)

Vì \(\frac{1}{5}< 1\) ⇒ H₂SO₄ dư

Dung dịch sau pư gồm: H₂SO₄ dư và ZnSO₄

Ta có: \(m_{dd}saupư=8,1+200=208,1\left(g\right)\)

Theo PT: \(n_{H_2SO_4}pư=n_{ZnO}=0,1\left(mol\right)\)

\(\Rightarrow n_{H_2SO_4}dư=0,5-0,1=0,4\left(mol\right)\)

\(\Rightarrow m_{H_2SO_4}=0,4\times98=39,2\left(g\right)\)

\(\Rightarrow C\%_{H_2SO_4}=\frac{39,2}{208,1}\times100\%=18,84\%\)

Theo pT: \(n_{ZnSO_4}=n_{ZnO}=0,1\left(mol\right)\)

\(\Rightarrow m_{ZnSO_4}=0,1\times161=16,1\left(g\right)\)

\(\Rightarrow C\%_{ZnSO_4}=\frac{16,1}{208,1}\times100\%=7,74\%\)

\(a)Zn+H_2SO_4\rightarrow ZnSO_4+H_2\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\\ b)Đặt:n_{Zn}=x\left(mol\right);n_{Fe}=y\left(mol\right)\\ Tacó:\left\{{}\begin{matrix}65x+56y=12,1\\x+y=0,2\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x=0,1\\y=0,1\end{matrix}\right.\\ \Rightarrow m_{Fe}=0,1.56=5,6\left(g\right);m_{Zn}=0,1.65=6,5\left(g\right)\\ c)n_{H_2SO_4}=n_{H_2}=0,2\left(mol\right)\\ \Rightarrow C\%_{H_2SO_{\text{ 4}}}=\dfrac{0,2.98}{196}.100=10\%\)

\(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)

PTHH: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)

            0,1       0,4

             0,1     0,2

             0        0,2          0,1        0,1

\(a,V_{H_2}=0,1.22,4=2,24\left(l\right)\\ b,m_{dd}=6,5+0,4.36,5+50-0,1.2=70,9\left(g\right)\\ C\%_{ZnCl_2}=\dfrac{0,1.136}{70,9}.100\%=19,18\%\)

$n_{Fe_2O_3} = 0,05(mol)$
$n_{H_2SO_4} = \dfrac{150.20\%}{98} = \dfrac{15}{49}(mol)$

$Fe_2O_3 + 3H_2SO_4 \to Fe_2(SO_4)_3 + 3H_2O$

Ta thấy : 

$n_{Fe_2O_3} : 1 < n_{H_2SO_4} :3$ nên $H_2SO_4$ dư

$m_{dd\ sau\ pư} = 8 + 150 = 158(gam)$

$n_{H_2SO_4\ dư} = \dfrac{15}{49} - 0,05.3 = \dfrac{153}{980}(mol)$

$n_{Fe_2(SO_4)_3} = 0,025(mol)$

$C\%_{H_2SO_4} = \dfrac{   \dfrac{153}{980}.98}{158} .100\% = 9,7\%$

$C\%_{Fe_2(SO_4)_3} = \dfrac{0,025.400}{158}.100\% = 6,3\%$