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

\(MgO+H_2SO_4\rightarrow MgSO_4+H_2O\)

Ta có: \(n_{H_2}=\dfrac{13,44}{22,4}=0,6\left(mol\right)\)

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

\(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,4.27}{14,8}.100\%\approx72,97\%\\\%m_{MgO}\approx27,03\%\end{matrix}\right.\)

b, Ta có: \(n_{MgO}=\dfrac{14,8-0,4.27}{40}=0,1\left(mol\right)\)

Theo PT: \(n_{H_2SO_4}=n_{H_2}+n_{MgO}=0,7\left(mol\right)\)

\(\Rightarrow m_{H_2SO_4}=0,7.98=68,6\left(g\right)\)

\(\Rightarrow m_{ddH_2SO_4}=\dfrac{68,6}{10\%}=686\left(g\right)\)

c, Theo PT: \(\left\{{}\begin{matrix}n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Al}=0,2\left(mol\right)\\n_{MgSO_4}=n_{MgO}=0,1\left(mol\right)\end{matrix}\right.\)

Ta có: m _{dd sau pư} = 14,8 + 686 - 0,6.2 = 699,6 (g)

\(\Rightarrow\left\{{}\begin{matrix}C\%_{Al_2\left(SO_4\right)_3}=\dfrac{0,2.342}{699,6}.100\%\approx9,78\%\\C\%_{MgSO_4}=\dfrac{0,1.120}{699,6}.100\%\approx1,72\%\end{matrix}\right.\)

làm j ba?

khó thiệt

a, PT: \(Na_2SO_3+2HCl\rightarrow2NaCl+SO_2+H_2O\)

Ta có: \(n_{Na_2SO_3}=\dfrac{12,6}{126}=0,1\left(mol\right)\)

Theo PT: \(n_{SO_2}=n_{Na_2SO_3}=0,1\left(mol\right)\)

\(\Rightarrow V_{SO_2}=0,1.22,4=2,24\left(l\right)\)

b, Theo PT: \(n_{NaCl}=n_{HCl}=2n_{Na_2SO_3}=0,2\left(mol\right)\)

\(\Rightarrow m_{NaCl}=0,2.58,5=11,7\left(g\right)\)

c, \(m_{HCl}=0,2.36,5=7,3\left(g\right)\)

\(\Rightarrow m_{ddHCl}=\dfrac{7,3}{10\%}=73\left(g\right)\)

d, Ta có: m _{dd sau pư} = 12,6 + 73 - 0,1.64 = 79,2 (g)

\(\Rightarrow C\%_{NaCl}=\dfrac{11,7}{79,2}.100\%\approx14,77\%\)

\(BaCl_2+Na_2CO_3\rightarrow NaCl+BaCO_3\downarrow\)

Hiện tượng: xuất hiện kết tủa trắng

\(X+H_2SO_4\rightarrow XSO_4+H_2\)

3,6/M                                 0,15

=>3,6/M=0,15

=>M=24

=>X là Mg