How many moles of hydrogen gas would be needed to react with excess carbon dioxide to produce 76.6 moles of water vapor

Answer 1

If at high temperature and pressure, you can get the following reaction:

4H₂ + CO₂ → CH₄ + 2H₂O ... balanced equation

Using the mol ratio of H₂ to H₂O of 4 mols : 2 mols, we can find the mols of H₂ needed to produce 76.6 mols of H₂O as follows:

76.6 mols H₂O x 4 mols H₂ / 2 mols H₂O = 153 mols H₂ needed (3 sig. figs.)