页数：61页文件大小：5.67 MB来源： Atkins’PhysChem物理化学ppt课件
本课件先讲界面效应：弯曲液面的附加压力与蒸气压变化、毛细上升与下降；随后转入混合物，引入偏摩尔量与化学势，并列出物质的量浓度、质量分数、摩尔分数等溶液组成表示方法。
Phases, Phase boundaries Three typical phase diagrams P
Now we link surface effects to the Helmholtz and Gibbs
Minimization of the surface are a of a liquid 6.9 Curved surfaces A curved surface Vapour pressure Ca
(a) Bubbles, cavities, and droplets Bubble: vapour and
(a) Bubbles, cavities, and droplets In bubble or cavity
(a) Bubbles, cavities, and droplets Curvature radius
(a) Bubbles, cavities, and droplets Nano bubbles: The B
(a) Bubbles, cavities, and droplets These images of nan
(a) Bubbles, cavities, and droplets Kelvin equation: Δ
(b) Nucleation For a droplets of water at 25 ° Cr = 1 μ
6.10 Capillary action Capillary action: liquids tend to
(a) Capillary rise The adhesive force < cohesive force
(b) The contact angle Between the edge of the meniscus
(b) The contact angle
粘附功(work of adhesion) (b) The contact angle
粘附功(work of adhesion) 在等温等压条件下，单位面积的液面与固体表面粘附时对外所作的最大功称为粘附功，它是液体能否润湿固体的一种量度。粘附功越大，液体越能润湿固体，液- 固结合得越牢。在粘附过程中，消失了单位液体表面和固体表面，产生了单位液- 固界面。粘附功就等于这个过程表面吉布斯能变化值的负值。 (b) The contact angle
浸湿功(work of immersion) (b) The contact angle
浸湿功(work of immersion) 等温、等压条件下，将具有单位表面积的固体可逆地浸入液体中所作的最大功称为浸湿功，它是液体在固体表面取代气体能力的一种量度。只有浸湿功大于或等于零，液体才能浸湿固体。在浸湿过程中，消失了单位面积的气、固表面，产生了单位面积的液、固界面，所以浸湿功等于该变化过程表面自由能变化值的负值。 (b) The contact angle
内聚功(work of cohesion) (b) The contact angle
内聚功(work of cohesion) 等温、等压条件下，两个单位液面可逆聚合为液柱所作的最大功称为内聚功，是液体本身结合牢固程度的一种量度。内聚时两个单位液面消失，所以，内聚功在数值上等于该变化过程表面自由能变化值的负值。 (b) The contact angle
We now go from the single systems to mixtures. Non - reacting substances Energetics
Thermodynamic Description of Mixtures Partial Molar Quantities Thermodynamics of Mi
(a) Partial Molar Volume 17.1 Partial Molar quantities the contribution that one component in a mixture makes to the total volume of a sam
(a) Partial Molar Volume 2 The different increase in total volume in the H 2 O / E tO H depends on the identit
(a) Partial Molar Volume 3 The partial molar volume of components of a mixture vary as the mixture goes from p
(a) Partial Molar Volume 4 The partial molar volume is the slope of a plot of total volume as the amount of J
(a) Partial Molar Volume 5 For a binary mixture, the composition can be changed by addition of dnAofAanddnBofB
(a) Partial Molar Volume 6 For example, if V has the following function V = A + B n A + C (n A 2 – 1) The part
(b) Partial Molar Gibbs Energies The concept of partial molar quantity can be applied to any extensive state functio
(b) Partial Molar Gibbs Energies Gibbs energy depends on composition, pressure and temperature (so, G may change if
Partial Molar quantities
(c) More on chemical potential Chemical potential tells us even more than just about variation inGG = U + Vp – ST
(c) More on chemical potential Chemical potential tells us even more than just about variation in G
(d) Gibbs - Duhem Equation Since G = n A μ A + n B μ B, and µ J depend on composition, for a binary mixture G
(d) Gibbs - Duhem Equation So, for the binary mixture, if one partial molar quantity increases, the other must
(d) Gibbs - Duhem Equation The experimental values of the partial volume of K 2 SO 4 (a q) at 298 K are given
(d) Gibbs - Duhem Equation dVA / db = 9.108 b - ½ The 1 st step is to change the variable V A to the molalityb
7.2 The thermodynamics of mixing Dependence of Gibbs energy on mixture composition is: G = n A μ A + n B μ BAt const
(a) The Gibbs energy of mixing The chemical potentials are at their “ pure values ” at this point. Gibbs energy is
(a) The Gibbs energy of mixing After mixing, the partial pressures of the gases are pAandpB, where the total press
Calculating Gibbs Energy of Mixing Two containers of equal volume are partitioned from one another, with one containin
Calculating Gibbs Energy of Mixing
(b) Other Thermodynamic Mixing Functions Since (∂ G / ∂ T) p, n = - S and It follows that for a mixture of perfect gases, th
(b) Other Thermodynamic Mixing Functions The isothermal isobaric enthalpy of mixing of two gases is found from Δ G = Δ H - T
7.3 Chemical Potentials of Liquids (a) Ideal solutions Relating to pure substances will be denoted with “ * ”. The che
7.3 Chemical Potentials of Liquids (a) Ideal solutions If another substance is present (e. g., a solute in the liquid)
7.3 Chemical Potentials of Liquids Raoult’ s Law 拉乌尔定律After experimenting with mixtures of similar liquids, the French
7.3 Chemical Potentials of Liquids Raoult’ s Law 拉乌尔定律Some mixtures obey Raoult’ s law very closely, especially when t
7.3 Chemical Potentials of Liquids Molecular Interpretation of Raoult’ s Law To consider the rate at which molecules l
7.3 Chemical Potentials of Liquids Molecular Interpretation of Raoult’ s Law The rate at which molecules return is pro
7.3 Chemical Potentials of Liquids Departure from Raoult’ s Law, Dilute Solutions Some solution mixtures be have very
7.3 Chemical Potentials of Liquids Departure from Raoult’ s Law, Dilute Solutions Ideal solution, consider the solvent
7.3 Chemical Potentials of Liquids (b) Ideal - dilute solutions: Henry’ s law The English chemist William Henry found
7.3 Chemical Potentials of Liquids (b) Ideal - dilute solutions: Henry’ s law The ideal - dilute solutions p B = xBKB
7.3 Chemical Potentials of Liquids The Validity of Raoult’ s & Henry’ s Laws
Using Henry’ s Law Estimate the molar solubility of oxygen in water at 25 o C and partial pressure of
Exercises (a) 7.5, 7,9, 15 Problems: 7.8 Homework
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