Em tham khảo nha :
\(\begin{array}{l}
7)\\
a)\\
A\\
2KCl{O_3} \to 2KCl + 3{O_2}\\
{n_{{O_2}}} = \dfrac{{6,72}}{{22,4}} = 0,3mol\\
{n_{KCl{O_3}}} = \dfrac{2}{3}{n_{{O_2}}} = 0,2mol\\
{m_{KCl{O_3}}} = 0,2 \times 122,5 = 24,5g\\
b)\\
B\\
{n_{{O_2}}} = \dfrac{{3,36}}{{22,4}} = 0,15mol\\
{n_{KCl{O_3}}} = \dfrac{2}{3}{n_{{O_2}}} = 0,1mol\\
{m_{KCl{O_3}}} = 0,1 \times 122,5 = 12,25g\\
8)\\
a)\\
A\\
b)\\
A
\end{array}\)