Em tham khảo nha :
\(\begin{array}{l}
1)\\
{m_{than}} = 5kg = 5000g\\
{m_C} = \dfrac{{5000 \times 90}}{{100}} = 4500g\\
C + {O_2} \xrightarrow{t^0} C{O_2}\\
{n_C} = \dfrac{m}{M} = \dfrac{{4500}}{{12}} = 375mol\\
{n_{{O_2}}} = {n_C} = 375mol\\
{V_{{O_2}}} = n \times 22,4 = 375 \times 22,4 = 8400l\\
{V_{kk}} = 5{V_{{O_2}}} = 5 \times 8400 = 42000l\\
2)\\
{n_{{O_2}}} = \dfrac{m}{M} = \dfrac{{3,2}}{{32}} = 0,1mol\\
{n_{C{O_2}}} = \dfrac{m}{M} = \dfrac{{8,8}}{{44}} = 0,2mol\\
{M_X} = \dfrac{m}{n} = \dfrac{{3,2 + 8,8}}{{0,1 + 0,2}} = 40g/mol
\end{array}\)
