Ta có:
\(n_{Fe}=\frac{25,25}{56}=0,45\left(mol\right)\)
\(3Fe+2O_{2\rightarrow}Fe_3O_4\)
0,45___0,3______
\(\Rightarrow V_{O2}=0,3.22,4=6,72\left(l\right)\)
\(2KClO_3\rightarrow2KCl+3O_2\)
\(n_{KClO3}=0,2\left(mol\right)\)
\(\Rightarrow m_{KClO3}=0,2.122,5=24,5\left(g\right)\)