What is the molecular mass of oxygen? 

32

The correct answer is option 2. 32. 

The molecular mass of oxygen (\(O_2\)) can be calculated by adding the atomic masses of its constituent atoms.

The atomic mass of oxygen (O) is approximately 16.00 atomic mass units (amu).

Since oxygen exists as a diatomic molecule (\(O_2\)), we need to multiply the atomic mass of oxygen by 2:

\[ \text{Molecular mass of } O_2 = 2 \times 16.00 \text{ amu} = 32.00 \text{ amu} \]

Therefore, the molecular mass of oxygen (\(O_2\)) is 32.00 atomic mass units.