a)
\(3Fe+2O_2\rightarrow Fe_3O_4\)
b)
\(n_{Fe3O4}=\frac{23,2}{232}=0,1\left(mol\right)\)
\(\rightarrow n_{Fe}=0,1.3=0,3\left(mol\right)\)
\(m_{Fe}=0,3.56=16,8\left(g\right)\)
c)
\(n_{O2}=0,1.2=0,2\left(mol\right)\)
\(\rightarrow V_{O2}=0,2.22,4=4,48\left(l\right)\)