1- CaCo3

Ca = 40   C = 12  O = 16

Ca = 40 x 1 = 40

C=   12 x 1 = 12

O = 16 x 3 = 48

40 + 12 + 48 = 100 g/mol

2-Mg3(PO4)2

3 x 24 + 2 x 31 + 8 X16 = 262 g/mol

3-Cr (OH)3

Fe (OH)3 = 56 + 3 * (16 + 1) = 107 g/mol

4-  NaNO3

Na= 23g

N= 14g

O3= 16x3

MM=  23+ 14 + 48

MM= 85g

5- Mn3 [Fe (CN)6]2

Ca₃[Fe(CN)₆]₂ =

40 x 3 + 56 x 2 + 12 x 12 + 14 x 12 = 544 u

6- H4SiO4

H = 1

S = 32

I= 127

O = 16  

4 x 1 + 32 + 127 + 4x16 = 227  g/mol.