a,
\(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
b, \(nFe=\dfrac{16,8}{56}=0,3\left(mol\right)\)
\(\Rightarrow nO_2=0,3.\dfrac{2}{3}=0,2\left(mol\right)\)
\(VO_2=0,2.24,79=4,958\left(l\right)\)
c, \(nFe_3O_4=0,1\left(mol\right)\)
\(mFe_3O_4=0,1.232=23,2\left(gam\right)\)