Calculate the volume of hydrogen gas that can be collected over water at 30.0°C at a 745.0 torr when 2000.0 g iron is reacted with excess hydrochloric acid according to the The vapor pressure of water at 30 C is 31.8 torr. 2 Fe(s) + 6 HCI(aq)-→ 2 FeC13(aq) + 3H2(g)