Đáp án:
Giải thích các bước giải:
3)
$2K+2HCl-->2KCl+H2$
x---------------x(mol)
$Zn+2HCl-->ZnCl2+H2$
y--------------y(mol)
Ta có hpt
$39x+65y=16,9$
$74,5x+136y=34,65$
=>$x=0,1,y=0,2$
=>%$mK=0,1.39/16,9.100$%$=23,08$%
=>%$mZn=100-23,08=76,92$%
4)
$Fe+2HCl-->FeCl2+H2$
$Zn+2HCl-->ZnCl2+H2$
$nH2=4,48/22,4=0,2(mol)$
=>$mH2=0,2.2=0,4(g)$
$nHCl=2nH2=0,4(mol)$
->$mHCl=0,4.36,5=14,6(g)$
=>$x=m ddHCl=14,6.100/10=146(g)$
$m=m KL=m Muố+mH2-mHCl=0,4+25,75-14,6=11,55(g)$