PTHH: \(2Mg+O_2\underrightarrow{t^o}2MgO\) (1)
\(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\) (2)
a) Gọi số mol của Mg là a (mol) \(\Rightarrow n_{Al}=\dfrac{2}{3}a\left(mol\right)\)
\(\Rightarrow24a+27\cdot\dfrac{2}{3}a=6,3\) \(\Rightarrow a=0,15\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{MgO}=0,15\left(mol\right)\\n_{Al_2O_3}=0,05\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{MgO}=0,15\cdot40=6\left(g\right)\\m_{Al_2O_3}=0,05\cdot102=5,1\left(g\right)\end{matrix}\right.\)
b) Theo các PTHH: \(\left\{{}\begin{matrix}n_{O_2\left(1\right)}=0,075\left(mol\right)\\n_{O_2\left(2\right)}=0,075\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\Sigma n_{O_2}=0,15\left(mol\right)\) \(\Rightarrow V_{O_2}=0,15\cdot22,4=3,36\left(l\right)\)