2H2O-đp->2H2+O2
..................0,4----0,2
nH2=8,96\22,4=0,4
=>=>VO2=0,2.22,4=4,48l
PTHH: H2O -đp-> H2 + 1/2 O2
0,4___________0,4___0,2(mol)
nH2= 8,96/22,4= 0,4(mol)
=> V(O2,đktc)=0,2.22,4=4,48(l)
b)mH2O= 0,4.18= 7,2(g)
=> V(H2O)= 7,2/1= 7,2(ml)