Có: \(\left\{{}\begin{matrix}n_{CO_2}+n_{CO}=\dfrac{8,96}{22,4}=0,4\\\dfrac{44.n_{CO_2}+28.n_{CO}}{n_{CO_2}+n_{CO}}=20.2=40\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}n_{CO}=0,1\\n_{CO_2}=0,3\Rightarrow n_{CO\left(pư\right)}=0,3\end{matrix}\right.\)
Theo ĐLBTKL: mA + mCO(pư) = mB + mCO2
=> mA = 20,4 + 0,3.44 - 0,3.28 = 25,2(g)