All of the elements in the periodic table are monoatomic except the 7 elements that are diatomic atoms. These 7 elements are hydrogen, nitrogen, oxygen, chlorine, bromine, iodine and fluorine. Monoatomic substances are those elements that are stable by themselves.
Answer : The number of moles of oxygen needed are, 1.5 moles.
Explanation :
The balanced chemical reaction will be:

Now we have to calculate the moles of oxygen.
From the balanced chemical reaction we conclude that,
As, 6 moles of water vapor produces from 5 moles of oxygen
So, 1.80 moles of water vapor produces from
moles of oxygen
Therefore, the number of moles of oxygen needed are, 1.5 moles.
Key differences between Mass and Weight
The weight may vary, but the mass is constant.
The mass is measured in kilograms (kg), while the weight is measured in newtons (N).
Mass refers to the amount of matter an object has, but the weight refers to the force of gravity acting on an object.
I need a little more context but I believe you are correct