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.
Answer:
The correct answer to this question is C
Explanation:
Kindly checkout the attached pic. It contains all your required questions.
You can tell if each side of the equation has the same molar mass.
The method of separating mixtures by means of their differences in the chemical properties of the components is less convenient because these methods requires reactions therefore needs energy, increasing the costs for the process.