Em tham khảo nha :
\(\begin{array}{l}
a)\\
4Al + 3{O_2} \xrightarrow{t^0} 2A{l_2}{O_3}\\
{n_{Al}} = \dfrac{{5,4}}{{27}} = 0,2mol\\
{n_{{O_2}}} = \dfrac{3}{4}{n_{Al}} = 0,15mol\\
{V_{{O_2}}} = 0,15 \times 22,4 = 3,36l\\
b)\\
{V_{kk}} = 5{V_{{O_2}}} = 5 \times 3,36 = 16,8l\\
c)\\
2KMn{O_4} \xrightarrow{t^0} {K_2}Mn{O_4} + Mn{O_2} + {O_2}\\
{n_{KMn{O_4}}} = 2{n_{{O_2}}} = 0,3mol\\
{m_{KMn{O_4}}} = 0,3 \times 158 = 47,4g
\end{array}\)