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8) Evaporation is the process where liquid particles obtain enough energy to overcome their IMF and go in the gas phase for the following conditions: on the surface and at any temperature where there is a liquid phase up to but not including the boiling point of the liquid. 9) Unlike the answer above for evaporation, boiling occurs in the bulk liquid where a liquid particle needs to move other liquid particles away ( to obtain enough space to form a gas) which the other liquid particles are being pushed by atmospheric pressure. So the liquid particle can not push any other liquid particles away unless its vapor pressure is equal or greater than the atmospheric pressure (that is holding the other liquid particle from moving and creating that space for the liquid particle trying to get into gas phase)., 10.Distillation is the physical process of separating a mixture of liquid (and other phases) by boiling point differences. Both hexane and octane have London Dispersion Forces (LDF). Since octane has the higher molar mass (MW) and has the most electrons, then it will have more Instantaneous Dipoles that cause a greater LDF. Since it has a greater IMF, it will have less vapor particles in the gas phase, a lower vapor pressure and therefore a higher boiling point. Using this line of reasoning, hexane will boil first (have the lower boiling point). 11. Heat of Vaporization or the energy added to boil the liquid away since it needs enough energy to overcome its IMF to be able to go into the gas phase. 12.& 13 See attached handout |