1 / 23

Chem 300 - Ch 23/#1 Today’s To Do List

Chem 300 - Ch 23/#1 Today’s To Do List. Start Chapter 23 Phase Diagrams…and Gibbs. Phase Diagrams. Solid-Liquid-Gas Behavior Usually a P-T Plot Phase: A homogeneous region of space. 1 -Phase region: An enclosed area Solid, liquid, gas phases

misu
Download Presentation

Chem 300 - Ch 23/#1 Today’s To Do List

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chem 300 - Ch 23/#1 Today’s To Do List • Start Chapter 23 • Phase Diagrams…and Gibbs

  2. Phase Diagrams • Solid-Liquid-Gas Behavior • Usually a P-T Plot • Phase: A homogeneous region of space. • 1-Phase region: An enclosed area • Solid, liquid, gas phases • 2-Phase line: A line separating 2 1-phase regions (where 2 phases are in equilibrium) • 3-Phase point: A point where 3 phases come together & are in equilibrium; A triple point.

  3. Josiah Willard Gibbs Josiah Willard Gibbs (1839 - 1903) has been reckoned as one of the greatest American scientists of the 19th century. He provided a sound thermodynamic foundation to much of Physical Chemistry. "Gibbs' Phase Rule" is well known to all in the field today. Yale educated, he was awarded the first Doctor of Engineering in the U.S., and was appointed Professor of Mathematical Physics at Yale in 1871. In 1873 he published his first major works, "Graphical Methods in the Thermodynamics of Fluids," and "A Method of Geometrical Representation of the Thermodynamic Properties of Substances by Means of Surfaces". In 1876 came his most famous paper: "On the Equilibrium of Heterogeneous Substances." From: http://jwgibbs.cchem.berkeley.edu/jwgibbs_bio.html

  4. Gibbs Phase Rule • f = 3 – p • f = # of degrees of freedom (P, T) • P = # of phases coexisting at equilibrium

  5. Phase Diagrams of Benzene

  6. MP of Benzene as function of Pressure

  7. BP of Benzene as Function of Pressure

  8. Phase Diagram of CO2

  9. Phase Diagrams of H2O

  10. MP of H2O as Function of Pressure

  11. The Critical Point • Properties of the vapor & liquid state become identical. • Transition “properties” become zero (DH, DG, DS, DVm).

  12. Orthobaric Liquid/Gas Densities of Benzene

  13. vapHm(T) of Benzene

  14. Multiple solid phases are common • Water has at least 6 high-Pressure phases. • Solid He is biphasic & strange…

  15. High-Pressure Phase Diagram of H2O

  16. High-Pressure Phase Diagram of H2O

  17. He Phase Diagram

  18. Another look at Gm • dGp = -SdT • Sm(g) >> Sm(l) > Sm(s)

  19. Gm(T) for Benzene: (a) near mp, (b) near bp

  20. Still another Look • dGT = +VmdP • Vm(g) >> Vm(l) Vm(s)

  21. Gm(P): (a) most substances(Vms < Vml), (b) H2O (Vms > Vml)

  22. Next Time • Chemical Potential • Phase Equilibrium • Clausius-Clapeyron Equation

More Related