Question

Calculate the molecular mass of $\mathrm{Co}{\left({\mathrm{NO}}_3\right)}_2.6{\mathrm{H}}_2\mathrm{O}$.

Answer 1

1. Molar mass is the sum of the masses of all the individual atoms present in a molecule or compound.
2. Cobalt (II) nitrate hexahydrate has chemical formula is $\mathrm{Co}{\left({\mathrm{NO}}_3\right)}_2.6{\mathrm{H}}_2\mathrm{O}$.
3. The atomic mass of nitrogen N is 14 u.
4. The atomic mass of hydrogen H is 1 u.
5. The atomic mass of oxygen is 16 u.
6. The atomic mass of cobalt is 60 u.

Molar mass of Cobalt (II) nitrate hexahydrate or $\mathrm{Co}{\left({\mathrm{NO}}_3\right)}_2.6{\mathrm{H}}_2\mathrm{O}$ = (Atomic mass of Cobalt) x 1 + (Atomic mass of Nitrogen) x 2 + 12 x (Atomic mass of Oxygen) + (Atomic mass of Hydrogen) x 2

Molar mass of Cobalt (II) nitrate hexahydrate or $\mathrm{Co}{\left({\mathrm{NO}}_3\right)}_2.6{\mathrm{H}}_2\mathrm{O}$= ( 60 x 1 ) + ( 14 x 2 ) + ( 12 x 16 ) + (1 2 x 1 )

= 292 u

The molar mass of Cobalt (II) nitrate hexahydrate or $\mathrm{Co}{\left({\mathrm{NO}}_3\right)}_2.6{\mathrm{H}}_2\mathrm{O}$ is 292 u.