The molecular mass of oxygen depends on whether you're referring to atomic oxygen (O) or molecular oxygen (O2).
Atomic Mass of Oxygen (O)
The atomic mass of a single oxygen atom is approximately 15.999 atomic mass units (u).
- Reference: 15.999 u Oxygen / Atomic mass
Molecular Mass of Oxygen Gas (O2)
Oxygen gas exists as a diatomic molecule (O2). Therefore, its molecular mass is calculated by adding the atomic masses of the two oxygen atoms:
Molecular mass of O2 = 2 Atomic mass of O
Molecular mass of O2 = 2 15.999 u
Molecular mass of O2 ≈ 31.998 u
Therefore, the molecular mass of oxygen gas (O2) is approximately 31.998 u.
| Element/Molecule | Molecular Mass (u) |
|---|---|
| Oxygen (O) | 15.999 |
| Oxygen (O2) | 31.998 |
