Đáp án:
75,68%
Giải thích các bước giải:
\(\begin{array}{l}
{m_{hhX}} = 15,05 - 5,55 = 9,5g\\
{M_{hhX}} = \dfrac{{190}}{7} \times 2 = \dfrac{{380}}{7}\,g/mol\\
{n_{hhX}} = \dfrac{{9,5}}{{\dfrac{{380}}{7}}} = 0,175\,mol\\
hh\,X:C{l_2}(a\,mol),{O_2}(b\,mol)\\
\left\{ \begin{array}{l}
71a + 32b = 9,5\\
a + b = 0,175
\end{array} \right.\\
\Rightarrow a = 0,1;b = 0,075\\
hh\,Y:Mg(x\,mol),Al(y\,mol)\\
{m_{hhY}} = 5,55g \Rightarrow 24x + 27y = 5,55(1)\\
BT\,e:\,2{n_{Mg}} + 3{n_{Al}} = 2{n_{C{l_2}}} + 4{n_{{O_2}}}\\
\Leftrightarrow 2x + 3y = 2 \times 0,1 + 4 \times 0,075(2)\\
(1),(2) \Rightarrow x = 0,175;y = 0,05\\
\% {m_{Mg}} = \dfrac{{0,175 \times 24}}{{5,55}} \times 100\% = 75,68\%
\end{array}\)