a) ZnS
[tex]\frac{mZn}{mS} = \frac{65u}{32u} = \frac{65}{32} = 65 : 32[/tex]
b) Cu2O
[tex]\frac{mCu}{mO} = \frac{64u * 2}{16 u} = \frac{128}{16} = \frac{8}{1} = 8 : 1[/tex]
c) Na2SO
mNa2 = 23u * 2 = 46 u
mS = 32 u
mO = 16 u
46 : 32 : 16 = 23 : 16 : 8
