Chemistry 122: vapor pressure

Chemistry 122: vapor pressure - Chemistry 122 Liquids boil...

Info icon This preview shows pages 1–2. Sign up to view the full content.

Chemistry 122 1/29/2014 Liquids boil when the vapor pressure (VP) equals to the air pressure of the surroundings, so a lower VP means a higher boiling point Due to solute- solvent intermolecular attraction, higher concentrations of nonvolatile solutes make it harder for solvent to escape the vapor phase. Therefore, the vapor pressure of a solution is lower than that of the pure solvent. The vapor pressure of a volatile solvent above a solution containing a non-volatile solute is proportional to the solvent’s concentration in solution: Raoult’s Law P solution = X solvent P solvent X A is the mole fraction of the solvent and P A is the vapor pressure of the pure solvent. Note: This is one of those times when you want to make sure you have the vapor pressure of the solvent . Xsolvent= # of moles solvent/ (moles solution) Moles solution  moles of solute +moles of solvent Example : vapor P of pure H 2 O at 20º C is P H2O = 17.5 torr. If we keep the temperature
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern