A 2.50 L flask at 17.0 degrees Celcius contains a misture of three gases, N2, He, and CO2, at partial pressures of 0.32 atm, 0.25atm and 0.40atm respectively. a. calculate the total pressure of the gas mixture b. calculate the volume, in litres at STP, occupied by the N2 and He if the CO2 was selectively removed.