3/
Gọi mol $K$: x
$Zn$: y
$K+2HCl \to KCl+1/2H_{2}$
x x
$Zn+2HCl \to ZnCl_{2}+H_{2}$
y y
$39x+65y=16,9$
$74,5x+136y=34,65$
⇒$\left \{ {{x=0,1} \atop {y=0,2}} \right.$
$\%mK=\frac{0,1.39}{16,9}.100=23,08\%$
$\%mZn=100-23,08=76,92\%$
4/
Gọi số mol $Fe$: x
$Zn$:y
$Fe+2HCl \to FeCl_{2}+H_{2}$
x x x
$Zn+2HCl \to ZnCl_{2}+H_{2}$
y y y
$nH_{2}=\frac{4,48}{22,4}=0,2$
$nHCl=2nH_{2}=0,2.2=0,4$
$mddHCl=\frac{0,4.36,5}{10\%}=146g$
$127x+136y=26,75$
$x+y=0,2$
⇒$\left \{ {{x=0,05} \atop {y=0,15}} \right.$
$mhh=mFe+mZn=0,05.56+0,15.65=12,55g$
