Number of moles of argon, nAr = 1.5 mol
Number of moles of argon, nCO2 = 3.5 mol
Total pressure of the gaseous mixture, P = 7.3 atm
According to Dalton’s law of partial pressure,
The partial pressure of CO2, PCO2 = Mole fraction of CO2 X Total pressure of the mixture.
or, PCO2 = nCO2/(nCO2 + nAr) X 7.3 atm = 3.5/(3.5 + 1.5) X 7.3 atm = 5.11 atm 5 atm