\(4.a/n_{Al}=\dfrac{5,4}{27}=0,2mol\\ 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

0,2       0,3                  0,1                  0,3

\(V_{H_2}=0,3.24,79=7,437l\\ b/C_{\%H_2SO_4}=\dfrac{0,3.98}{150}\cdot100=19,6\%\\ c/m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2g\)

\(5.a/n_{MgO}=\dfrac{4}{40}=0,1mol\\ MgO+2HCl\rightarrow MgCl_2+H_2O\)

0,1            0,2             0,1              0,1

\(C_{\%HCl}=\dfrac{0,2.36,5}{200}\cdot100=3,65\%\\ b/C_{\%MgCl_2}=\dfrac{0,1.95}{200+4}\cdot100=4,66\%\\ c/NaOH+HCl\rightarrow NaCl+H_2O\\ n_{NaOH}=n_{HCl}=0,2mol\\ V_{NaOH}=\dfrac{0,2}{1}=0,2l=200ml\)

Theo ĐL bao toàn nguyên tố, số mol H2SO4 tham gia phan ứng là:

n(H2SO4) = n(H2) = 2,24/22,4 = 0,1 mol

→ m(H2SO4) = 0,1.98 = 9,8g

Khối lượng dd H2SO4 đa d ng:

m(dd H2SO4) = m9H2SO4)/C% = 9,8/10%  = 98g

Khối lượng dung dich thu được sau pư:

m(dd sau) = m(dd H2SO4) + m(hh KL) - m(H2) = 98 + 3,68 - 0,1.2 = 101,48g

 => Đáp án A

Bài 13: 

a) \(n_{H_2}=\dfrac{5,4}{27}=0,2\left(mol\right)\)

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

            0,2---------------------------->0,3

=> V_H2 = 0,3.24,79 = 7,437 (l)

b)

PTHH: Fe₂O₃ + 3H₂ --t^o--> 2Fe + 3H₂O

                          0,3------->0,2

=> m_Fe = 0,2.56 = 11,2 (g)

a.\(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)

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

 0,2                                              0,3   ( mol )

\(V_{H_2}=0,3.24,79=7,437l\)

b.\(Fe_2O_3+3H_2\rightarrow\left(t^o\right)2Fe+3H_2O\)

                    0,3            0,2                    ( mol )

\(m_{Fe}=0,2.56=11,2g\)

tk

Bài 13: 

a) nH2=5,4/27=0,2(mol)

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

            0,2---------------------------->0,3

=> V_H2 = 0,3.24,79 = 7,437 (l)

b)

PTHH: Fe₂O₃ + 3H₂ --t^o--> 2Fe + 3H₂O

                          0,3------->0,2

=> m_Fe = 0,2.56 = 11,2 (g)

\(4.\\ a/n_{Al}=\dfrac{5,4}{27}=0,2mol\\2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)

\(0,2......0,3............0,1...............0,3\)

\(V_{H_2}=0,3.24,79=7,437l\\ b.C_{\%H_2SO_4}=\dfrac{0,3.98}{150}\cdot100=19,6\%\\ c.m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2g\)

\(7.\\a) n_{H_2SO_4}=\dfrac{100.9,8}{100.98}=0,1mol\\ ZnO+H_2SO_4\rightarrow ZnSO_4+H_2O\\ n_{ZnO}=n_{ZnSO_4}=n_{H_2SO_4}=0,1mol\\ m_{ZnO}=0,1.81=8,1g\\ b)C_{\%ZnSO_4}=\dfrac{0,1.161}{8,1+100}\cdot100=14,8\%\)

\(9.\\ a)n_{H_2}=\dfrac{2,479}{24,79}=0,1mol\\ Mg+2HCl\rightarrow MgCl_2+H_2\)

\(0,1.....0,2.........0,1........0,1\)

\(m_{Mg}=0,1.24=2,4g\\ m_{MgO}=8,4-2,4=6g\\ b)n_{MgO}=\dfrac{6}{40}=0,15mol\\ MgO+2HCl\rightarrow MgCl_2+H_2O\\ n_{HCl}=0,15.2+0,2=0,5mol\\ m_{ddHCl}=\dfrac{0,5.36,5}{3,65}\cdot100=500g\)

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

\(n_{Al}=\dfrac{5,4}{54}=0,1\left(mol\right)\)

Theo PTHH: \(n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Al}=0,05\left(mol\right)\)   

\(\Rightarrow m_{Al_2\left(SO_4\right)_3}=0,05\cdot342=17,1\left(g\right)\)

Hiệu suất phản ứng là:

\(H=\dfrac{17,1}{18}\cdot100\%=95\%\)

b) Theo PTHH: \(n_{H_2}=\dfrac{0,1\cdot3}{2}=0,15\left(mol\right)\)

\(\Rightarrow V_{H_2,dkc}=0,15\cdot24,79=3,7185\left(l\right)\)