Dilute Solution and Colligative Properties(3) S.J.T.0. Phase Transformation and Applications Page 6/45 p 溶剂 溶液 固体溶剂 △T T T ti 温度 图5-6稀溶液中溶液的沸点升高 图5-7稀溶液的凝固点下降 SJTU Thermodynamics of Materials Fall 2010 X.J.Jin Lecture 13 Phase Rule
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2010 © X. J. Jin Lecture 13 Phase Rule Page 6/45 Dilute Solution and Colligative Properties (3)
Osmotic Pressure(1) S.J.T.0. Phase Transformation and Applications Page 7/45 a-u=RT'Inx4 Raoult's law 半透膜！ HA-H=RTIn(1-xB)=-RTXB -Etan Aqueous solution (impure water) Flexible wall Π=RT Semipermeable Pure water membrane Figure 7.14 Osmotic pressure. SJTU Thermodynamics of Materials Fall 2010 X.J.Jin Lecture 13 Phase Rule
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2010 © X. J. Jin Lecture 13 Phase Rule Page 7/45 Osmotic Pressure (1) A A A − = RT ln x o μ μ ( ) A A B RTxB − = RT ln 1− x = − o μ μ ∫ +Π − = = − Π PP A A V AdP V A o μ μ A B V x Π = RT Raoult’s law 半透膜！
规则溶液 S.J.T.0. Phase Transformation and Applications Page 8/45 ·非理想溶液 Iny= 0 S*M =0 GM=H”=0xAxB SJTU Thermodynamics of Materials Fall 2010 X.J.Jin Lecture 13 Phase Rule
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2010 © X. J. Jin Lecture 13 Phase Rule Page 8/45 规则溶液 • 非理想溶液 ( ) 2 2 ln 1 A B A x RT x RT = = − ω ω γ A B xs M xs M G = H = ωx x M = 0 xs S
Regular Solution Atomistic Interpretation(3) S.J.T.0. Phase Transformation and Applications Page 9/45 For the regular solution:S=0 GM=H应=rAXB i8=H数+xB aH” H8=@XXB+xx0(XA-XB) HB=ox XS ↑ 破 Justify the algebraic form c RT in a regular solution. XA XB→ Figure 7.13 Plot of excess enthalpy of mixing versus com- position for a nonideal solution. SJTU Thermodynamics of Materials Fall 2010 X.J.Jin Lecture 13 Phase Rule
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2010 © X. J. Jin Lecture 13 Phase Rule Page 9/45 Regular Solution Atomistic Interpretation (3) For the regular solution: = 0 M S A B xsM xsM G = H = ωx x T B xs M A xs M xs B x H H H x ⎟⎟⎠⎞ ⎜⎜⎝⎛ ∂∂ = + ( ) B T A B A B A xsB xx x H x x x ⎟⎟⎠⎞ ⎜⎜⎝⎛ ∂ ∂ = + ω ω ( ) A B A A B xs H B = ωx x + x ω x − x 2 A xs H B = ωx B xs GB = RT lnγ 2 ln B A x RTω γ = Justify the algebraic form of the activity coefficient in a regular solution
Regular Solution:Atomistic Interpretation(1) S.J.T.0. Phase Transformation and Applications Page 10/45 A,B二元完全无序分布 Random distribution 只考虑最近邻原子间的相互作用 Z:coordination number NA个A原子与N个B原子混合形成规则溶液 EAA:bonding energy Table 7.1 Bond Energies After Mixing Atoms A and B in a Solid Solution Number of Bonds Energy per Bond Energy NAB EAB NAN N Z EAB NA NL EA ZEA N NAB Nr ge SJTU Thermodynamics of Materials Fall 2010 X.J.Jin Lecture 13 Phase Rule
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Fall 2010 © X. J. Jin Lecture 13 Phase Rule Page 10/45 Regular Solution: Atomistic Interpretation (1) A,B二元完全无序分布 只考虑最近邻原子间的相互作用 NA个A原子与NB个B原子混合形成规则溶液 Random distribution Z: coordination number EAA: bonding energy Z Z