8.9. Phase d iagrams Understand the meaning of different zones, lines and points in a phase Be able to use a phase diagram to explain different phenomena 8.10. Two additional concentration representation Mole fraction(X): percentage of moles(between solute and solvent) 8.11. Colligative properties: only depend on the number of solute particles (a). Vapor pressure lowering-Raoult's law Understand the reason of vapor pressure lowering from molecular point of vIew For nonvolatile solute: P= Po solvent X Xsolvent: P= Po solvent x Xsolute For two volatile components: Ptotal =P1,0 XI+ P2,0x X2 Calculate the ratios of two volatile components in both liquid and gas phases the one with higher vapor pressure will be enriched in the gas phase Distillation (b). Boiling point elevation ◆ Increase of Tb:△Tb=Tb-Tb=Kb×m;( Kb is a constant for the solvent,m is the molality of solute) Using the boiling point elevation to calculate the solute's Molar mass (c). Freezing point depr Decrease ofTE. ATf= Tf-Tf= KfX m;(Kf is a constant for the solvent, m is the molality of solute) (d ). Osmotic pressure II=c R*T Using the osmotic pressure to calculate the solute's Molar mass Summary and Exercise Class #3 Midterm Exam I class8.9．Phase diagrams  Understand the meaning of different zones, lines and points in a phase diagram  Be able to use a phase diagram to explain different phenomena 8.10．Two additional concentration representation:  Molality (m): # of solute moles per solvent mass in kg  Mole fraction (X): percentage of moles (between solute and solvent) 8.11．Colligative properties: only depend on the number of solute particles (a)．Vapor pressure lowering – Raoult’s law  Understand the reason of vapor pressure lowering from molecular point of view  For nonvolatile solute: P = P0, solvent × Xsolvent; ΔP = P0, solvent × Xsolute  For two volatile components: Ptotal = P1,0 × X1 + P2,0 × X2  Calculate the ratios of two volatile components in both liquid and gas phases – the one with higher vapor pressure will be enriched in the gas phase → Distillation (b)．Boiling point elevation:  Increase of Tb: ΔTb = Tb ’ – Tb = Kb × m; (Kb is a constant for the solvent, m is the molality of solute)  Using the boiling point elevation to calculate the solute’s Molar mass. (c)．Freezing point depresstion  Decrease of Tf: ΔTf = Tf ’ – Tf = Kf × m; (Kf is a constant for the solvent, m is the molality of solute) (d)．Osmotic pressure  Π = Csolute * R * T  Using the osmotic pressure to calculate the solute’s Molar mass. Summary and Exercise Class #3 1 class Midterm Exam 1 class