Mg + 2HCl → MgCl2 + H2 (1)
MgO + 2HCl → MgCl2 + H2O (2)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
Theo PT1: \(n_{Mg}=n_{H_2}=0,1\left(mol\right)\)
\(\Rightarrow m_{Mg}=0,1\times24=2,4\left(g\right)\)
\(\Rightarrow m_{MgO}=4,4-2,4=2\left(g\right)\)
\(\Rightarrow\%Mg=\dfrac{2,4}{4,4}\times100\%=54,55\%\)
\(\%MgO=\dfrac{2}{4,4}\times100\%=45,45\%\)
Theo PT1: \(n_{HCl}=2n_{Mg}=2\times0,1=0,2\left(mol\right)\)
\(n_{MgO}=\dfrac{2}{40}=0,05\left(mol\right)\)
Theo PT2: \(n_{HCl}=2n_{MgO}=2\times0,05=0,1\left(mol\right)\)
\(\Rightarrow\Sigma n_{HCl}=0,1+0,2=0,3\left(mol\right)\)
\(\Rightarrow V_{HCl}=\dfrac{0,3}{2}=0,15\left(l\right)=150ml\)
