Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.
At 90 ˚C, the vapor pressure of toluene is 400 torr while that of o-xylene is 150 torr.
- What is the composition of a liquid mixture that will boil at 90 ˚C when the external pressure is 0.5 atmosphere?
- What is the composition of the vapor?
- What assumptions have you made?
FYI:1 atm =760 torr
Consider a mixture of 2,2,4-trimethyl pentane (iso-octane) and ethanol at 25 ˚C. At 0.2748 mole fraction of iso-octane, the partial vapor pressure of iso-octane is 48.31 torr and the vapor pressure of pure iso-octane is 59.03 torr. The partial vapor pressure of ethanol in the solution is 46.91 torr and the vapor pressure of pure ethanol is 49.31 torr.
- Is the mixture ideal or nonideal? If it is nonideal, does it deviate positively or negatively from ideality? Explain your answer.
- Could you ever have a solution where one component deviated positively from ideality and the other had a negative deviation?