CHEM 1062 Lecture Notes - Lecture 5: Vant (Band), Colligative Properties, Molar Mass
Document Summary
Chem 1062: lecture #5 applications of colligative properties and ionic atmospheres. Using colligative properties to find solute molar mass: Each colligative property is proportional to solute concentration. Osmotic pressure is most accurate to find solute molar mass. Psolute = xsolute * po solvent solute. Where both xsolvent and xsolute are mole fractions in liquid phase. Total vapor pressure: ptotal = psolvent + psolute = (xsolvent * po solvent) * (xsolute * po solute) The pressure of each volatile component lowers the vapor pressure of the other. The vapor has a higher mole fraction than the more volatile component. I = (measured value for electrolyte solution)/(expected value for non-electrolyte solution) Vapor pressure lowering: p = i(xsolute * po. Most strong electrolyte solutions are not ideal, i is typically less than the value expected. To explain non-ideal behavior, picture clustered positive ions around negative ions to form an ionic atmosphere of net opposite charge.