CTHH của nhôm Nitrat là Al(NO3)3
M(Al(NO3)3)= M(Al)+ 3.M(N)+3.3.M(O)= 27+3.14+9.16=213(g/mol)
\(\%mAl=\frac{27}{213}.100\approx12,676\%\\ \%mN=\frac{3.14}{213}.100\approx19,718\%\\ \rightarrow\%mO\approx100\%-\left(12,676\%+19,718\%\right)\approx67,606\%\)