CHM 1046 Lecture Notes - Lecture 41: Mole Fraction, Colligative Properties, Molality
Document Summary
Parts per million (ppm) (parts by mass)10^6 or mass percentage10^4. Parts per billion (ppb) (parts by mass)10^9 or mass percentage10^7. Mole fraction (moles of solute)/(moles of solute +solvent) Colligative properties a property of a solution that depends only on the number of solute particles present in the solution and not on their identity. Van"t hoff (i) factor: number of particles a substance breaks into. Vapor pressure lowering-concepts the vapor pressure is the pressure of gas that exists in equilibrium with its respective liquid at equilibrium, rate of evaporation= rate of condensation. Raoult"s law vapor pressure of a substance in a mixture is proportional to the mole fraction of that substance. A non-volatile solute creases the mole fraction of the solvent in the diagram, p0(b)=0, therefore p(b)=0 and p=p(a) Boiling point is a quantity that is fairly easily measure, and we can detect small differences.
