Question

Question #98436

Answer 1

Oxygen Atom `~~ 16`
Oxygen Gas (that we inhale) `~~32`

Explanation:

This question is quite confusing considering that we tend to refer to oxygen (the element with symbol O) and to the oxygen (the gas we inhale `O_2`) using the same term.

Since oxygen the element consist only of 1 atom of Oxygen, then we will use the atomic weight of oxygen for this mass (`mass_O ~~ 16`). However since oxygen rarely exists as purely a single atom, we say that the molar mass of oxygen is 32 or `mass_(O_2) = 32 g/(mol)`.

Now when computing for empirical formula sample problems, use `16 g/(mol)` since it corresponds to the mass of 1 atom of oxygen. Just remember to multiply the value to the subscript of Oxygen when you need to determine the molar masses of the compounds you need to compute for.