Notez inmultirile cu * si fractiile cu /
Zn + H2SO4-> ZnSO4 + H2
MZn =65
1 mol Zn = 65 g
MZnSO4 = 65 + 32 + 4*16 = 161
1 mol Zn = 161 g
MH2=2*1=2
1 mol H = 2 g
In 13 g Zn avem x g ZnSO4 si y g H2
In 65 g Zn avem 161g ZnSO4 si 2g H2
13/65=x/161=>x=13*161/65 =32.2 g ZnSO4
13/65=y/2=>y=13*2/65 =0.4 g H2