Bài 1 :
$n_{Zn}=26/65=0,4mol$
$PTHH :$
$Zn+2HCl\to ZnCl_2+H_2↑$
a.Theo pt :
$n_{HCl}=2.n_{Zn}=2.0,4=0,8mol$
$⇒m_{HCl}=0,8.36,5=29,2g$
$⇒m_{dd\ HCl}=\dfrac{29,2}{7,3\%}=400g$
b/Theo pt :
$n_{H_2}=n_{Zn}=0,4mol$
$⇒V_{H_2}=0,4.22,4=8,96l$
Bài 2 :
$m_{H_2SO_4}=490.5\%=24,5g$
$⇒n_{H_2SO_4}=24,5/98=0,25mol$
$2Al+3H_2SO_4\to Al_2(SO_4)_3+3H_2↑$
a.Theo pt :
$n_{Al_2(SO_4)_3}=1/3.n_{H_2SO_4}=\dfrac{1}{12}mol$
$⇒m_{Al_2(SO_4)_3}=\dfrac{1}{12}.342=28,5g$
b.Theo pt :
$n_{H_2}=n_{H_2SO_4}=0,25mol$
$⇒V_{H_2}=0,25.22,4=5,6l$