What mole ratio would you use to calculate how many mole of oxygen gas would be?

The mole ratio one would need to calculate will be the ratio of grams of O2 are in one mole; that's the atomic mass of oxygen from the periodic table.

Oxygen has an atomic mass of 15.998 (most of the time, rounding to 16 is fine). But remember, oxygen always exists in nature as a diatomic molecule (two atoms covalently bonded together) as O2...so (32 grams O2/1 mole O2)

If you like my answer, please vote me a 'brainliest'; I'm trying to improve my site rank :-)