If 1.0 liter of oxygen at 2.0 atm pressure, 1.00 liters of nitrogen at 1.0 atm pressure, and 1.0 liters of helium at 2.0 atm pressure, are all mixed in a 1.0 liter vessel with no change in temperature, what is the final pressure of the mixture in the 1.0 liter vessel? what would the new pressure be if i transferred to a 3.0l container?