Giải thích các bước giải:
\[\begin{array}{l} \qquad {\kern 1pt} 2KMn{O_4}\xrightarrow{t^\circ}{K_2}Mn{O_4} + Mn{O_2} + {O_2}\\ {\rm{mol}}{\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} \;\;\;0,4{\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} \leftarrow \qquad {\kern 1pt} \qquad {\kern 1pt} \qquad {\kern 1pt} \qquad {\kern 1pt} \;\;0,2\\ \qquad {\kern 1pt} 3Fe + 2{O_2}\xrightarrow{t^\circ}F{e_3}{O_4}\\ {\rm{mol}}\qquad {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} 0,2{\mkern 1mu} {\kern 1pt} {\mkern 1mu} {\kern 1pt} \leftarrow \;\; 0,1\\ {n_{F{e_3}{O_4}}} = \frac{{23,2}}{{232}} = 0,1\;{\rm{mol}} \end{array}\]
Theo PTHH: \[\begin{array}{l}
{n_{KMn{O_4}}} = 0,4\;{\rm{mol}}\\
\Rightarrow {m_{KMn{O_4}}} = 158 \cdot 0,4 =63,2\;{\rm{gam}}
\end{array}\]
