Hydrochloric acid reacts with magnesium to produce hydrogen gas and magnesium chloride. Reacting magnesium with excess hydrochloric acid produces 1204 mL of hydrogen gas that is collected over water. How many grams of hydrogen gas are produced at 25.0 °C and 1.00 atm? The vapor pressure of water at 25.0 °C is 23.8 mm Hg.