Câu 9:
\(2M+2HCl\rightarrow2MCl+H_2\uparrow\\ n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\Rightarrow n_M=2.0,1=0,2\left(mol\right)\\ \Rightarrow M_M=\dfrac{7,8}{0,2}=39\left(\dfrac{g}{mol}\right)\\ \Rightarrow M\left(I\right):Kali\left(K=39\right)\)
Bài 10:
\(Mg+2HCl\rightarrow MgCl_2+H_2\\ n_{MgCl_2}=\dfrac{9,5}{95}=0,1\left(mol\right)\\ \Rightarrow n_{Mg}=n_{MgCl_2}=0,1\left(mol\right)\\ \Rightarrow\%m_{Mg}=\dfrac{0,1.24}{13,2}.100\approx18,182\%\\ \Rightarrow\%m_{Ag}\approx100\%-18,182\%=81,818\%\)