Is the molecular weight of O2 15.999u or 32?

It is 2 x 15.999 = ?

Ohhh just realized what I missed, thank you.

The molecular weight of O2 is actually 32.

To understand why, we need to break down the concept of molecular weight. Molecular weight refers to the sum of the atomic weights (also known as atomic masses) of all the atoms in a molecule.

Looking at the molecular formula of O2, we have two oxygen (O) atoms bonded together. The atomic weight of oxygen is approximately 15.999 u, but that refers to the atomic weight of a single oxygen atom.

To calculate the molecular weight of O2, we simply multiply the atomic weight of oxygen by 2 (since there are two oxygen atoms in the molecule).

Molecular weight of O2 = (atomic weight of oxygen) * 2
= 15.999 u * 2
= 32 u

Therefore, the correct molecular weight of O2 is 32 u.