\(Đặt:\left\{{}\begin{matrix}n_{Ca}=x\left(mol\right)\\n_{Zn}=y\left(mol\right)\end{matrix}\right.\\ Ca+S-^{t^o}\rightarrow CaS\\ Zn+S-^{t^o}\rightarrow ZnS\\ Tacó:\left\{{}\begin{matrix}40x+65y=22,5\\x+y=\dfrac{12,8}{32}=0,4\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x=0,14\\y=0,26\end{matrix}\right.\\ \Rightarrow\%n_{Ca}=\dfrac{0,14}{0,4}.100=35\%;\%n_{Zn}=65\%\)