Assuming that the gas is ideal, we can use the ideal gas equation PV=nRT to calculate for the number of moles. Then, multiply the molar mass of the gas to obtain the mass. We do as follows:
PV = nRT
n = PV / RT
n = 1.1 atm (3.7x10^9 L) / 0.08205 L-atm/mol-K (280.15) = 177061931.3 mol H2
Mass = (177061931.3 mol H2) 18.02 g/mol ( 1 kg / 1000g) ( 2.2 lb / 1 kg ) = 7019443.21 lb H2
