Question

cho hh A gồm rượu etylic và axit axetic . cho 21,1 g A pư vs K dư thu đc 4,48l khí . tính phần trăm khối lượng hh A

Answer 1

Gọi \(\left\{{}\begin{matrix}n_{C2H5OH}:x\left(mol\right)\\n_{CH3COOH}:y\left(mol\right)\end{matrix}\right.\)

Ta có:

\(n_{H2}=\frac{4,48}{22,4}=0,2\left(mol\right)\)

\(2C_2H_5OH+2K\rightarrow C_2H_5OK+H_2\)

\(2CH_3COOH+2K\rightarrow2CH_3COOK+H_2\)

Giải hệ PT:

\(\left\{{}\begin{matrix}4x+100y=21,1\\0,5x+0,5y=0,2\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,35\\y=0,05\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%m_{C2H5OH}=\frac{0,35.46}{21,1}.100\%=76,3\%\\\%m_{CH3COOH}=100\%-76,3\%=23,7\%\end{matrix}\right.\)