Câu hỏi 22

\(\begin{array}{l}m\,g\,A\left\{ \begin{array}{l}X:Gly - Ala - Val - Gly:x\\Y:Gly - Val - Ala:y\end{array} \right. + KOH\,vua\,du \to 257,36\,g\,cran\\{n_{{H_2}O}} = {n_{peptit}} = x + y\\{n_{NaOH}} = 4x + 3y\\ \Rightarrow \left\{ \begin{array}{l}\frac{x}{y} = \frac{4}{3}\\(302x + 245y) + 56(4x + 3y) = 257,36 + 18(x + y)\,[BTKL]\end{array} \right. \Rightarrow \left\{ \begin{array}{l}x = 0,32\\y = 0,24\end{array} \right.\\ \Rightarrow m = 302x + 245y = 155,44g\end{array}\)

Đáp án A