Câu 1 :
$n_{ZnO}=8,1/81=0,1mol$
$PTHH : ZnO+H_2\to Zn+H_2O$
a/Theo pt :
$n_{Zn}=n_{ZnO}=0,1mol$
$⇒m_{Zn}=0,1.65=6,5g$
b/Theo pt :
$n_{H_2}=n_{ZnO}=0,1mol$
$⇒V_{H_2}=0,1.22,4=2,24l$
Câu 2 :
$n_{H_2}=3,36/22,4=0,15mol$
$2H_2+O_2\overset{t^o}\to 2H_2O$
Theo pt :
$n_{O_2}=1/2.n_{H_2}=1/2.0,15=0,075mol$
$⇒V=V_{O_2}=0,075.22,4=1,68l$
Câu 3 :
$m_{NaOH}=50.20\%=10g$