Calcium hydride, CaH2, reacts with water to form hydrogen gas: CaH21s2 + 2 H2O1l2¡Ca1OH221aq2 + 2 H21g2 This reaction is sometimes used to inflate life rafts, weather balloons, and the like, when a simple, compact means of generating H2 is desired. How many grams of CaH2 are needed to generate 145 L of H2 gas if the pressure of H2 is 110 kPa at 21 °C?