$n_{Zn}=16,25/65=0,25mol$
$a/2Zn+O_2→2ZnO$
b/Theo pt :
$n_{O_2}=1/2.n_{Zn}=1/2.0,25=0,125mol$
$⇒V_{O_2}=0,125.22,4=2,8l$
c/Theo pt :
$n_{ZnO}=n_{Zn}=0,25mol$
$⇒m_{ZnO}=0,25.81=20,25g$
$d/2KClO_3 \overset{t^o}\to 2KCl + 3O2$
Theo pt :
$n_{KClO_3}=2/3.n_{O_2}= 2/3.0,125= 1/12 mol$
$⇒ m_{KClO_3}=1/12.122,5= 10,2g$