Question

How do we find the molar mass of Co(NO 3) 2 . 6 H2O ?

Answer 1

Let's start,

Molar mass of Cobalt : 58.93 g/mol.
Molar mass of Nitrogen: 14 g/mol.
Molar mass of Oxygen: 16 g/mol.
Molar mass of Hydrogen: 1.0 g/mol.

So molar mass of (NO3)2 will be
[14+(16 x 3)] x 2 = 124 g/mol.

And molar mass of Anhydrous Co(NO3)2 will be
58.93 + 124= 182.93 g/mol

Similarly, molar mass of H2O is 18 g/mol.
Therefore molar mass of hexahydrates will be 18 x 6= 108 g/mol.

And molar mass of Co(NO3)2 .6H2O is 182.93+ 108= 290.93 g/mo