Here's why:
* Oxygen's Atomic Mass: The atomic mass of one oxygen atom is approximately 16 atomic mass units (amu).
* Oxygen Molecule: An oxygen molecule (O₂) is made up of two oxygen atoms.
* Molar Mass: The molar mass of a substance is the mass of one mole of that substance. Since one mole contains 6.022 x 10²³ particles (Avogadro's number), the molar mass is numerically equal to the atomic or molecular mass, but expressed in grams per mole (g/mol).
Therefore:
* Molecular mass of O₂ = 16 amu/atom * 2 atoms = 32 amu
* Molar mass of O₂ = 32 g/mol
