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 12.0 L of H2 gas if the pressure of H2 is 740. torr at 19°C?

10.2 grams

Explanation:

The balanced chemical reaction is :

According to the ideal gas equation:

P = Pressure of the gas = 740 torr =  0.97 atm    (760torr=1atm)

V= Volume of the gas = 12.0 L

T= Temperature of the gas = 19°C = 292 K    

R= Gas constant = 0.0821 atmL/K mol

n= moles of gas

According to stoichiometry:

2 moles of hydrogen are generated by = 1 mole of

Thus 0.48 moles of hydrogen are generated by = moles of

Mass of  

Thus 10.2 grams of are needed to generate 12.0 L of hydrogen gas if the pressure of hydrogen is 740. torr at 19°C

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.