To determine the volume of the gas mixture, we first need to determine the total pressure of the mixture. To do this, we use the definition of the partial pressure of a component in the gas mixture. The partial pressure is the pressure of a component as if it were alone in the container. It is equal to the mole fraction of the component times the total pressure of the system. From this, we determine total pressure.
Pneon = xneonP
P = Pneon / xneon
P = 8.87 kPa / (225 / (225 + 320 + 175))
P = 8.87 kPa / 0.3125 = 28.384 kPa
Assuming ideal gas, we use PV=nRT to calculate for the volume,
PV = nRT
V = nRT / P
n = 225 mg ( 1 mmol / 20.18 mg) + 320 mg ( 1 mmol / 16.05 mg ) + 175 mg ( 1 mmol / 39.95 mg ) = 35.47 mg = 35467.0 g
V = 35467.0 (8.314) (300) / (28384) = 3116.68 m^3
