{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

BasicThermo3

BasicThermo3 - Review of classical thermodynamics...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
MSE 3050, Phase Diagrams and Kinetics, Leonid Zhigilei Review of classical thermodynamics Fundamental Laws, Properties and Processes (3) Fundamental equations The Helmholtz Free Energy The Gibbs Free energy Changes in composition Chemical potential Thermodynamic relations Reading: Chapter 5.1 5.9 of Gaskell or the same material in any other textbook on thermodynamics
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
MSE 3050, Phase Diagrams and Kinetics, Leonid Zhigilei Fundamental equations Combined statement of 1 st and 2 nd Laws of Thermodynamics: dU = TdS – PdV This equation gives us ¾ Relationship between the dependent variable U and independent variables V and S: U = U(S,V) or dU = ( w U/ w S) v dS + ( w U/ w V) s dV ¾ The criteria for equilibrium: in a system of constant V and S, the internal energy has its minimum value, or, in a system of constant U and V, the entropy has its maximum value. The problem is that the pair of independent variables (V,S) is rather inconvenient entropy is hard to measure or control. We want to have fundamental equations with independent variables that is easier to control. The two convenient choices are: P and T pair the best choice from the practical point of view, easy to control/measure. For systems with constant pressure the best suited state function is the Gibbs free energy (also called free enthalpy) G = H - TS V and T pair easy to examine in statistical mechanics. For systems with constant volume (and variable pressure), the best suited state function is the Helmholtz free energy A = U – TS Any state function can be used to describe any system (at equilibrium, of course), but for a given system some are more convenient than others.
Image of page 2
MSE 3050, Phase Diagrams and Kinetics, Leonid Zhigilei The Helmholtz Free Energy A = U – TS dA = dU – TdS – SdT Combining this equation with dU = TdS – PdV we get dA = – PdV – SdT - fundamental equation A = A(T,V) dA = ( w A/ w T) V dT + ( w A/ w V) T dV Comparing the equations we see that S = – ( w A/ w T) V P = – (
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern