\(2KMnO_4\rightarrow K_2MnO_4+MnO_2+O_2\)
0,1_________0,05______0,05_____0,05
\(n_{KMnO4}=\frac{15,8}{39+55+16.4}=0,1\left(mol\right)\)
\(\Rightarrow m_{K2MnO4}=0,05.\left(39.2+55+16.4\right)=9,58\left(g\right)\)
\(\Rightarrow m_{MnO2}=0,05.\left(55+32\right)=4,35\left(g\right)\)