How many moles are in 64 grams of oxygen gas?
There are 2 moles of oxygen molecules; there are 4 moles of oxygen atoms.
This is always an issue when we deal with (typically!) diatomic gases. Most inorganic chemists speak of dihydrogen, and dinitrogen, and dihalogen in order to avoid confusion.
We assume standard state conditions, under which regime we deal with
Thus there are