Step-by-step explanation:
Assuming STP
EACH 22.4 liters is a mole of H2
320 m^3 = 320 000 liters
320 000 liters / ( 22.4 liters/mole) = 14285.7 moles
From periodic table , each mole of H2 is 2.016 gm
18285. 7 moles * 2.016 gm/ mole = 28799.97 gm = ~ 28.8 kg