Under certain circumstances, carbon dioxide, CO2(g), can be made to react with hydrogen gas, H2(g), to produce methane, CH4(g), and water vapor, H2O(g):CO2(g)+4H2(g)→CH4(g)+2H2O(g)
Question: How many moles of hydrogen gas would be needed to react with excess carbon dioxide to produce 88.1 moles of water vapor?
(please provide working out and the answer in mol)