Answer:
To determine the number of moles of oxygen consumed to produce 68.1g of water, we need to know the amount of hydrogen in the water. Since water has two hydrogen atoms and one oxygen atom, the molar mass of water is 18.015 g/mol.
Using the molar mass of water, we can calculate the number of moles of water produced:
68.1 g ÷ 18.015 g/mol = 3.78 mol
Since there are two hydrogen atoms in each molecule of water, there must be twice as many moles of hydrogen as there are moles of water:
3.78 mol × 2 = 7.56 mol of hydrogen
Finally, we can use the balanced chemical equation for the reaction of hydrogen and oxygen to form water to determine the number of moles of oxygen consumed:
2H2 + O2 -> 2H2O
For every 1 mole of oxygen consumed, 2 moles of water are produced. Therefore, the number of moles of oxygen consumed is:
7.56 mol H2O ÷ 2 = 3.78 mol O2
So, 3.78 moles of oxygen would be consumed to produce 68.1g of water.