\(n_{O_2}=\dfrac{7,437}{24,79}=0,3\left(mol\right)\)
PT: \(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
a, \(n_{Al}=\dfrac{4}{3}n_{O_2}=0,4\left(mol\right)\)
\(\Rightarrow m_{Al}=0,4.27=10,8\left(g\right)\)
b, \(n_{Al_2O_3}=\dfrac{2}{3}n_{O_2}=0,2\left(mol\right)\)
\(\Rightarrow m_{Al_2O_3}=0,2.102=20,4\left(g\right)\)