2Mg + O2 → 2MgO (1)
4Al + 3O2 → 2Al2O3 (2)
Gọi \(x,y\) lần lượt là số mol của Mg và Al
Ta có: \(\left\{{}\begin{matrix}24x+27y=15,6\\40x+51y=28,4\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,2\left(mol\right)\\y=0,4\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow m_{Mg}=0,2\times24=4,8\left(g\right)\)
\(\Rightarrow\%m_{Mg}=\dfrac{4,8}{15,6}\times100\%=30,77\%\)
\(m_{Al}=0,4\times27=10,8\left(g\right)\)
\(\Rightarrow\%m_{Al}=\dfrac{10,8}{15,6}\times100\%=69,23\%\)
Theo PT1: \(n_{O_2}=\dfrac{1}{2}n_{Mg}=\dfrac{1}{2}\times0,2=0,1\left(mol\right)\)
Theo PT2: \(n_{O_2}=\dfrac{3}{4}n_{Al}=\dfrac{3}{4}\times0,4=0,3\left(mol\right)\)
\(\Rightarrow\Sigma n_{O_2}=0,1+0,3=0,4\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,4\times22,4=8,96\left(l\right)\)