a) nZn=6,5:65=0,1(mol)
pt: Zn + 2HCl -> ZnCl2 + H2 (1)
theo pt có: nH2=nZn=0,1(mol)
-> VH2=0,1.22,4=2,24(l)
b) Đổi: 100ml=0,1(l)
theo pt (1) có: nHCl=2nH2=2.0,1=0,2(mol)
->CM=nddHCl/VddHCl=0,2:0,1=2(M)
c) pt: H2(k) + CuO(r) -to-> Cu(r) +H2O(l)
theo pt ta có: nH2=nCuO=0,1(mol)
-> mCuO=0,1.80=8(g)