For a balloon ride, the balloon must be inflated with helium to a volume of 1500 m3 at sea level. The balloon will rise to an altitude of about 12 km, where the temperature is about -52 oC and the pressure is about 20 kPa. Assume the initial gas temperature and pressure to be 295 K and 1 atm.
How much helium should be put into the balloon?
Express your answer to two significant figures and include the appropriate units