Calcium hydride, CaH2, reacts with water to form hydrogen gas. CaH2(s) + 2 H2O(l) Ca(OH)2(aq) + 2 H2(g) This reaction is sometimes used to inflate life rafts, weather balloons, and the like, where a simple, compact means of generating H2 is desired. How many grams of CaH2 are needed to generate 16.0 L of H2 gas if the pressure of H2 is 750. torr at 25°C?