Answer:
[tex]182.933~ \text{g mol}^{-1}[/tex]
Explanation:
[tex]\text{Atomic mass of cobalt(Co)} = 58.933~u\\\\\text{Atomic mass of nitrogen(N)}= 14~u\\\\\text{Atomic mass of oxygen(O)}=16~u\\\\\text{Molar mass of}~ \text{Co}\left(\text{NO}_3} \right)_2 = 58.933 + 2(14 +16 \times 3)~ \text{g mol}^{-1}\\\\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~=(58.933 + 124)~ \text{g mol}^{-1}\\\\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~=182.94~ \text{g mol}^{-1}[/tex]
