\(a.n_{NaOH}=\dfrac{8}{40}=0,2mol\\ 2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\\ n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,1mol\\ n_{Fe}=\dfrac{11,2}{56}=0,2mol\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ n_{H_2SO_4}=n_{H_2}=n_{Fe}=0,2mol\\ m=m_{H_2SO_4}=\left(0,1+0,2\right).98=29,4g\\ b.V_{H_2}=0,2.24,79=4,958l\)

\(2NaOH\left(0,2\right)+H_2SO_4\left(0,1\right)\rightarrow Na_2SO_4+2H_2O\)

\(Fe\left(0,2\right)+H_2SO_4\left(0,2\right)\rightarrow FeSO_4+H_2\left(0,2\right)\)

\(n_{NaOH}=\dfrac{8}{40}=0,2\left(mol\right)\)

\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

\(\Rightarrow n_{H_2SO_4}=0,1+0,2=0,3\left(mol\right)\)

\(\Rightarrow m_{H_2SO_4}=0,3.98=29,4\left(g\right)\)

b/ Thể tích H₂ là: \(V_{H_2}=0,2.22,4=4,48\left(l\right)\)

a)

\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

PTHH: Fe + H₂SO₄ --> FeSO₄ + H₂

            0,2----------------------->0,2

=> V_H2 = 0,2.22,4 = 4,48 (l)

b) 

PTHH: 2H₂ + O₂ --t^o--> 2H₂O

             0,2-->0,1

PTHH: 2KMnO₄ --t^o--> K₂MnO₄+ MnO₂ + O₂

                  0,2<------------------------------0,1

=> \(m_{KMnO_4}=0,2.158=31,6\left(g\right)\)

c) \(n_{O_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)

PTHH: 3Fe + 2O₂ --t^o--> Fe₃O₄

Xét tỉ lệ: \(\dfrac{0,2}{3}>\dfrac{0,1}{2}\) => Fe dư

a.\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

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

0,2                                      0,2   ( mol )

\(V_{H_2}=0,2.22,4=4,48\left(l\right)\)

b.\(2H_2+O_2\rightarrow\left(t^o\right)2H_2O\)

  0,2       0,1                       ( mol )

\(2KMnO_4\rightarrow\left(t^o\right)K_2MnO_4+MnO_2+O_2\uparrow\)

     0,2                                                        0,1  ( mol )

\(m_{KMnO_4}=0,2.158=31,6\left(g\right)\)

c.\(n_{O_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)

      \(3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\)

Xét: \(\dfrac{0,2}{3}\) > \(\dfrac{0,1}{2}\)                        ( mol )

--> Sắt không cháy hết

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

Ta có: \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}n_{H_2SO_4}=0,15\left(mol\right)=n_{H_2}\\n_{Al_2\left(SO_4\right)_3}=0,05\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{H_2SO_4}=0,15\cdot98=14,7\left(g\right)\\m_{Al_2\left(SO_4\right)_3}=0,05\cdot342=17,1\left(g\right)\\V_{H_2}=0,15\cdot22,4=3,36\left(l\right)\end{matrix}\right.\)

a) \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)

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

______0,1--->0,15-------->0,05------->0,15

=> m_H2SO4 = 0,15.98 = 14,7 (g)

b) V_H2 = 0,15.22,4 = 3,36 (l)

c) m_Al2(SO4)3 = 0,05.342 = 17,1 (g)

a, \(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

\(n_{HCl}=\dfrac{7,3}{36,5}=0,2\left(mol\right)\)

PT: \(Fe+2HCl\rightarrow FeCl_2+H_2\)

Xét tỉ lệ: \(\dfrac{0,2}{1}>\dfrac{0,2}{2}\), ta được Fe dư.

Theo PT: \(n_{Fe\left(pư\right)}=\dfrac{1}{2}n_{HCl}=0,1\left(mol\right)\Rightarrow n_{Fe\left(dư\right)}=0,2-0,1=0,1\left(mol\right)\)

\(\Rightarrow m_{Fe\left(dư\right)}=0,1.56=5,6\left(g\right)\)

b, \(n_{H_2}=\dfrac{1}{2}n_{HCl}=0,1\left(mol\right)\Rightarrow V_{H_2}=0,1.22,4=2,24\left(l\right)\)

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

b, \(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

Theo PT: \(n_{FeSO_4}=n_{Fe}=0,2\left(mol\right)\Rightarrow m_{FeSO_4}=0,2.152=30,4\left(g\right)\)

c, \(n_{H_2}=n_{Fe}=0,2\left(mol\right)\Rightarrow V_{H_2}=0,2.22,4=4,48\left(l\right)\)

d, \(n_{H_2SO_4}=n_{Fe}=0,2\left(mol\right)\Rightarrow C_{M_{H_2SO_4}}=\dfrac{0,2}{0,2}=1\left(M\right)\)

NaOH tác dụng với H2SO4 sao lại có HCl dư ở đây?