Đáp án:
a. mHgO=55,25-20=35,25 g
nHgO=$\frac{35,25}{217}$ =0,15 mol
HgO+H2->Hg+H2O(1)
(1)->nH2=nHgO=0,15 mol
VH2=0,15.22,4=3,36 l
%MgO=$\frac{20}{55,25}$.100=36,19%
%HgO=100%-36,19%=63,81%
(1)->nHg=nHgO=0,15 mol
mHg=0,15.201=30,15 g
b. Zn+HCl->ZnCl2+H2(2)
(2)->nZn=nH2=0,15 mol
mZn=0,15.65=9,75 g