Question

What is the total vapor pressure in atm of a solution created by combining 2.78 moles of toluene and 7.65 moles of benzene at 350K? At 350K Pvap, toluene = 0.33 atm and Pvap, benzene = 0.95 atm

Answer 1

Given,

Moles of toluene = 2.78

Moles of Benzene = 7.65

=> Total Moles = 2.78 + 7.65 = 10.43 moles

Pvap for toluene = 0.33 atm

Pvap for benzene = 0.95 atm

Mole fraction of toluene = 2.78 / 10.43 = 0.267

and Mole fraction of benzene = 7.65 / 10.43 = 0.733

Total Vapor Pressure = (Mole fraction of toluene x Pvap, toluene) + (Mole fraction of benzene x Pvap, benzene)

=> Total Vapor Pressure = (0.267 x 0.33) + (0.733 x 0.95) = 0.08811 + 0.69635 = 0.78446 atm = 0.78 atm