A sample of zinc metal is allowed to react completely with an excess of hydrochloric acid. The hydrogen gas produced is collected over water at 25.0 o C. 7.80 L of the gas was collected at a total pressure of 0.980 atm. The vapor pressure of water at 25 o C is 23.8 mm Hg. a. Write the balanced chemical equation. b. Calculate the mass (in grams) of zinc metal that was consumed in the reaction.