$n_{CO_2}=\dfrac{13,2}{44}=0,3(mol)$
$\to n_C=n_{CO_2}=0,3(mol)$
$\to \%m_C=\dfrac{0,3.12.100}{4,56}=78,95\%$
$n_{H_2O}=\dfrac{3,16}{18}=0,1756(mol)$
$\to n_H=2n_{H_2O}=0,3512(mol)$
$\to \%m_H=\dfrac{0,3512.1.100}{4,56}=7,7\%$
Nung $4,56g$ $A$ thu $\dfrac{4,56.0,67}{5,58}=0,5475l$ $N_2$
$\to n_{N}=2n_{N_2}=0,049(mol)$
$\to \%m_N=\dfrac{0,049.14.100}{4,56}=15\%$$
$\to \%m_O=-1,65\%$ (bạn xem lại đề)