a)
\(n_{KMnO_4\left(bđ\right)}=\frac{126,4}{158}=0,8\left(mol\right)\)
\(n_{KMnO_4\left(pư\right)}=\frac{0,8.80}{100}=0,64\left(mol\right)\)
PTHH: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\uparrow\)
________0,64---------->0,32-------->0,32---->0,32_____(mol)
=> \(m_{K_2MnO_4}=0,32.197=63,04\left(g\right)\)
b) \(m_{MnO_2}=0,32.87=27,84\left(g\right)\)
c) \(V_{O_2}=0,32.22,4=7,168\left(l\right)\)
d) \(m_{rắn}=m_{KMnO_4}\) (không pư) + \(m_{MnO_2}+m_{K_2MnO_4}\)
= \(158\left(0,8-0,64\right)+27,84+63,04\)
= 116,16 (g)