16 mol of oxygen were react with excess hydrogen gas, how many moles of water would be produced

32 moles of water.

Explanation:

The balanced chemical equation for formation of water:

As can be seen from the chemical equation, 2 moles of hydrogen react with 1 mole of oxygen to form 2 moles of water.

As it is given that hydrogen is present in excess, hydrogen is the excess reagent and oxygen is the limiting reagent as it limits the formation of product.

According to stoichiometry:

1 mole of Oxygen gives 2 moles of water

Thus 16 moles of oxygen will give=of water.

32 moles of water will be produced.