\(n_{Al_2O_3}=\dfrac{4,08}{102}=0,04\left(mol\right)\\ n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
PTHH: 4Al + 3O2 --to--> 2Al2O3
0,08<----------------0,04
\(\rightarrow H=\dfrac{0,08}{0,1}.100\%=80\%\)
\(n_{Al_2O_3}=\dfrac{4,08}{102}=0,04\left(mol\right)\\
n_{Al}=\dfrac{2.7}{27}=0,1\left(mol\right)\\
pthh:4Al+2O_2\underrightarrow{t^o}2Al_2O_3\)
0,1 0,05
=> \(H\%=\dfrac{0,04}{0,05}.100\%=80\%\)