Em tham khảo nha:
\(\begin{array}{l}
a)\\
{n_K} = \dfrac{m}{M} = \dfrac{{3,9}}{{39}} = 0,1\,mol\\
{n_{Fe}} = \dfrac{m}{M} = \dfrac{{11,2}}{{56}} = 0,2\,mol\\
{n_{C{O_2}}} = \dfrac{m}{M} = \dfrac{{5,5}}{{44}} = 0,125\,mol\\
{n_{F{e_3}{O_4}}} = \dfrac{m}{M} = \dfrac{{58}}{{232}} = 0,25\,mol\\
b)\\
{n_{C{O_2}}} = \dfrac{V}{{22,4}} = \dfrac{{6,72}}{{22,4}} = 0,3\,mol\\
{n_{S{O_2}}} = \dfrac{V}{{22,4}} = \dfrac{{10,08}}{{22,4}} = 0,45\,mol\\
{n_{{H_2}}} = \dfrac{V}{{22,4}} = \dfrac{{3,36}}{{22,4}} = 0,15\,mol
\end{array}\)
