Aluminum reacts with hydrochloric acid to produce aluminum chloride and hydrogen gas. If 927 mL of hydrogen gas is collected by displacement of water at 740.0 mm Hg and 20. °C, what mass of Al was used? The vapor pressure of water is 17.5 mm Hg. (Atomic weights: Al = 26.98, H = 1.008, Cl = 35.45, O = 16.00).