$n_{Al}=5,4/27=0,2mol$
$PTHH :$
$2Al+3H_2SO_4\to Al_2(SO_4)_3+3H_2↑(*)$
$\text{a/Theo pt :}$
$n_{H_2}=3/2.n_{Al}=3/2.0,2=0,3mol$
$⇒V_{H_2}=0,3.22,4=6,72l$
$b/n_{Cu}=6,4/64=0,1mol$
$PTHH :$
$CuO+H_2\overset{t^o}\to Cu+H_2O(1)$
$Fe_2O_3+3H_2\overset{t^o}\to 2Fe+3H_2O(2)$
$\text{Theo pt (1) :}$
$n_{CuO}=n_{Cu}=0,1mol$
$⇒m_{CuO}=0,1.80=8g$
$n_{H_2(1)}=n_{Cu}=0,1mol$
$⇒n_{H_2(2)}=0,3-0,1=0,2mol$
$\text{Theo pt (2) :}$
$n_{Fe_2O_3}=1/3.n_{H_2}=1/3.0,2=\dfrac{0,2}{3}mol$
$⇒m_{Fe_2O_3}=\dfrac{0,2}{3}.160=\dfrac{32}{3}g$
$\text{c/Theo pt (*) :}$
$n_{H_2SO_4}=3/2.n_{Al}=3/2.0,2=0,3mol$
$⇒m_{H_2SO_4}=0,3.98=29,4g$
$⇒m_{ddH_2SO_4}=\dfrac{29,4}{10\%}=294g$
