1) \(2KClO3-->2KCl+3O2\)
\(n_{KClO3}=\frac{12,25}{122,5}=0,1\left(mol\right)\)
\(n_{O2}=\frac{3}{2}n_{KClO3}=0,15\left(mol\right)\)
\(V_{02}=0,15.22,4=5,6\left(l\right)\)
2) \(2KClO3-->2KCl+3O2\)
\(n_{O2}=\frac{48}{32}=1,5\left(mol\right)\)
\(n_{KClO3}=\frac{2}{3}n_{O2}=1\left(mol\right)\)
\(m_{KClO3}=1.122,5=122,5\left(g\right)\)
3) \(2KMnO4-->K2MnO4+MnO2+O2\)
\(n_{O2}=\frac{2,8}{22,4}=0,125\left(mol\right)\)
\(n_{KMnO4}=2n_{O2}=0,25\left(mol\right)\)
\(m_{MnO4}=0,25.158=39,5\left(g\right)\)