Question

What is the formula mass of the iodine molecule?

Answer 1

Iodine is a diatomic molecule, and we work out the mass of $I_2$.
Explanation:
The atomic mass of iodine is $126.9\cdot g\cdot mo{l}^{-1}$, and thus its formula mass is $253.8\cdot g\cdot mo{l}^{-1}$, as we know that formula mass: $126.9\times 2=253.8g/mol$