7.49 The chemical reaction of hydrogen with oxygen produces water. 2 H2(g) + O2(g) -> 2 H2O(g) a. How many moles of O2 are required to react with 2.0 moles of H2 b. How many moles of H2 are needed to react with 5.0 moles of O2? c. How many moles of H2O form when 2.5 moles of O2 reacts?