Molecular formula of water is H2O
Thus, one atom of 'O' combines with 2 atoms of 'H' for form 1 molecule of H2O
Here, atomic weight of O = 16 g/mol
and, molecular weight of H2O = 18 g/mol
Now,1 mole of O (16 g/mol) ≡ 1 mole of water (18 g/mol)
∴ 2.5 mole of O (40 g/mol) ≡ 2.5 moles of water (45 g/mol)
Answer: 45 grams of H2O are produced when 2.50 moles of oxygen are used