DOCSLIB.ORG

CHAPTER VII Electrochemical Thermodynamics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
CHAPTER VII Electrochemical Thermodynamics CHAPTER VII Electrochemical Thermodynamics Prepared by Dr. Ehteram A. Noor Associate Prof. of physical chemistry Revised by Dr. Salwa Al-Rashid Associate Prof. of physical chemistry Ehteram A Noor- Kng Abdulaziz University ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Gibbs Function and Electrical Work Start with the First Law of Thermodynamics and some standard thermodynamic relations. We find dE dq dw dq = T dS dw PdV dwelectrical dE TdS PdV dwelectrical dHP dEP PdV dGT dHT TdS dGT dET ,P PdV TdS dGT TdS PdV dwelectrical PdV TdS dGT,P dwelectrical And therefore, the Gibbs function is at the heart of electrochemistry, for it identifies the amount of work we can extract electrically from a system. Ehteram A Noor- Kng Abdulaziz University ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Gibbs and the Cell Potential Here we can easily see how this Gibbs function relates to a potential. welectrical PotentialCh arg e EQ GT ,P welectrical and Q nF GT ,P nFE By convention, we identify work which is negative with work which is being done by the system on the surroundings. And negative free energy change is identified as defining a spontaneous process. Note how a measurement of a cell potential directly calculates the Gibbs free energy change for the process. Ehteram A Noor- Kng Abdulaziz University ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Variation of e.m.f with temperature One of the most rewarding aspects of electrochemistry is that ΔS values spring directly from studies of the temperature variation of e.m.f. dGo dEo Since o o nF G nFE dT dT o where ( dE / dT ) is the temperature coefficient of the electrochemical cell Look at this equation important relationship between numerical factors and Eo can be obtained Entropy (S) o G o Thermodynamic relationship S T P dEo dEo S o S o nF dT dT nF Ehteram A Noor- Kng Abdulaziz University ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Enthalpy (H) Thermodynamic relationship H o Go TS o Since o Go nFE dEo H o nFE o T (nF ) dT dEo H o nF(E o T ) dT dEo S o nF Ehteram A Noor- Kng Abdulaziz University dT ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Ehteram A Noor- Kng Abdulaziz University ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Ehteram A Noor- Kng Abdulaziz University ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Ehteram A Noor- Kng Abdulaziz University ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ________________________________________________________ Text resources J. M. Seddon and J. D. Gale, Thermodynamics and Statistical Mechanics, The Royal Society of Chemistry, (2001) G. W. Castellan, Physical Chemistry, 2nd Edn. (1971), Adison-Wesley Publishing Company, Amesterdam I. Tinoco, Jr, K. Sauer and J. C. Wang, Physical Chemistry, (1978), Prentice-Hall, Inc., New Jersey W. J. Moore, Basic Physical Chemistry, (1983), Prentice-Hall, Inc., New Jersey J. R. Wan and A. P. H. Peters, Concise Chemical Thermodynamics, 2nd Edn. (1996), Taylor & Francis e-Library.http://www.ebookstore.tandf.co.uk/.” R. J. Silbey and R. A. Alberty, Physic al Chemistry, 3rd Edn. (2001), John wiley & Sons, New York. I. N. Levine, Physical Chemistry, 5th Edn. (2003), McGraw-Hill, New York. Electronic Web resources mmadou.eng.uci.edu/classes/MAE-212/MAE212.II.pptx Ehteram A. Noor- King AbdulAziz University .
Load more

Recommended publications
  • Chemistry Courses 2005-2006
    Chemistry Courses 2005-2006 Autumn 2005 Chem 11101 General Chemistry I, Variant A Lee Chem 11102 General Chemistry I, Variant B Norris Chem 12200 Honors General Chemistry I Levy Chem 22000 Organic Chemistry I Yu Chem 22300 Intermediate Organic Chemistry Mrksich Chem 26100 Quantum Mechanics Mazziotti Chem 30100 Advanced Inorganic Chemistry Hopkins Chem 30900 Bioinorganic Chemistry He Chem 32100 Physical Organic Chemistry I Ismagilov Chem 32200 Organic Synthesis and Structure Rawal Chem 32600 Protein Fundamentals Piccirilli Chem 36100 Wave Mechanics & Spectroscopy Butler Chem 36400 Chemical Thermodynamics Dinner Winter 2006 Chem 11201 General Chemistry II, Variant A Scherer Chem 11202 General Chemistry II, Variant B Butler Chem 12300 Honors General Chemistry II Dinner Chem 20100 Inorganic Chemistry I Hillhouse Chem 22100 Organic Chemistry II Rawal Chem 23100 Honors Organic Chemistry II Kozmin Chem 26200 Thermodynamics Norris Chem 26700 Experimental Physical Chemistry Levy Chem 30200 Synthesis & Physical Methods in Inorganic Chemistry Jordan Chem 30400 Organometallic Chemistry Bosnich Chem 32300 Tactics of Organic Synthesis Yamamoto Chem 32400 Physical Organic Chemistry II Mrksich Chem 36200 Quantum Mechanics Freed Chem 36300 Statistical Mechanics Mazziotti Chem 38700 Biophysical Chemistry Lee Spring 2006 Chem 11301 General Chemistry III, Variant A Kozmin Chem 11302 General Chemistry III, Variant B Guyot-Sionnest Chem 20200 Inorganic Chemistry II Jordan Chem 22200 Organic Chemistry III Kent Chem 23200 Honors Organic Chemistry III Yamamoto Chem 22700 Advanced Organic / Inorganic Laboratory (8 students) He Chem 26300 Chemical Kinetics and Dynamics Sibner Chem 26800 Computational Chemistry & Biology Freed Chem 30600 Chemistry of the Elements Hillhouse Chem 31100 Supramolecular Chemistry Bosnich Chem 32500 Bioorganic Chemistry Piccirilli Chem 32900 Polymer Chemistry Yu Chem 33000 Complex Systems Ismagilov Chem 36500 Chemical Dynamics Scherer Chem 36800 Advanced Computational Chemistry & Biology Freed .
    [Show full text]
  • Entropy and Life
    Entropy and life Research concerning the relationship between the thermodynamics textbook, states, after speaking about thermodynamic quantity entropy and the evolution of the laws of the physical world, that “there are none that life began around the turn of the 20th century. In 1910, are established on a firmer basis than the two general American historian Henry Adams printed and distributed propositions of Joule and Carnot; which constitute the to university libraries and history professors the small vol- fundamental laws of our subject.” McCulloch then goes ume A Letter to American Teachers of History proposing on to show that these two laws may be combined in a sin- a theory of history based on the second law of thermo- gle expression as follows: dynamics and on the principle of entropy.[1][2] The 1944 book What is Life? by Nobel-laureate physicist Erwin Schrödinger stimulated research in the field. In his book, Z dQ Schrödinger originally stated that life feeds on negative S = entropy, or negentropy as it is sometimes called, but in a τ later edition corrected himself in response to complaints and stated the true source is free energy. More recent where work has restricted the discussion to Gibbs free energy because biological processes on Earth normally occur at S = entropy a constant temperature and pressure, such as in the atmo- dQ = a differential amount of heat sphere or at the bottom of an ocean, but not across both passed into a thermodynamic sys- over short periods of time for individual organisms. tem τ = absolute temperature 1 Origin McCulloch then declares that the applications of these two laws, i.e.
    [Show full text]
  • Chemical Thermodynamics and Staged Unit Operations
    Beginning of Course Memorandum (BOCM) University of Virginia Fall, 2013 CHE 3316 Chemical Thermodynamics and Staged Unit Operations Revised October 22 Instructor: John O'Connell: Office Chemical Engineering 310; Voice (434) 924-3428; E-mail: [email protected] Office Hours: TR1400-1730, Others TBA GTA: Sabra Hanspal: Office CHE 217A; Voice 4-1476; E-mail: [email protected]; Office Hours: MF 12-2 PM Class Meetings: CHE 005, TR 0930-1045, T 1300-1350 Texts: "Lectures in Thermodynamics, Volume 2 (Beta Version)", by J.M. Haile & J.P. O'Connell, 2008 - 12, Electronic copy on CD available from instructor for $15. Total 641 pages. "Separation Process Engineering, 3rd Ed.", by P.C. Wankat, Prentice Hall, 2012. References: “Physical and Chemical Equilibrium for Chemical Engineers, 2nd Ed.” by N. de Nevers, Wiley-Interscience, New York, 2012. "Introduction to Chemical Engineering Thermodynamics, 7th Ed.," by J.M. Smith, H.C. Van Ness, and M.M. Abbott (SVNA). McGraw-Hill, New York, 2005. "Chemical, Biochemical, & Engineering Thermodynamics, 4th Ed.," by S.I. Sandler, John Wiley, 2006. "Schaum's Outline of Thermodynamics with Chemical Applications, 2nd Ed.," by H.C. Van Ness & M.M.Abbott, Schaum's Outlines, McGraw-Hill, 1989. "Lectures in Thermodynamics, Volume 1," by J.M. Haile, Macatea Productions, 2002. “Unit Operations of Chemical Engineering, 7th Ed.”, W. McCabe, J. Smith, & P. Harriott, New York, McGraw-Hill, 2004. “Principles of Chemical Separations with Environmental Applications,” R.D. Noble & P.A. Terry, Cambridge, UK, Cambridge University Press, 2004. “Perry’s Chemical Engineers’ Handbook, 8th Ed.,” D. Green & R. Perry, New York, McGraw-Hill, 2007.
    [Show full text]
  • Chapter 19 Chemical Thermodynamics
    Chapter 19 Chemical Thermodynamics Entropy and free energy Learning goals and key skills: Explain and apply the terms spontaneous process, reversible process, irreversible process, and isothermal process. Define entropy and state the second law of thermodynamics. Calculate DS for a phase change. Explain how the entropy of a system is related to the number of possible microstates. Describe the kinds of molecular motion that a molecule can possess. Predict the sign of DS for physical and chemical processes. State the third law of thermodynamics. Compare the values of standard molar entropies. Calculate standard entropy changes for a system from standard molar entropies. Calculate the Gibbs free energy from the enthalpy change and entropy change at a given temperature. Use free energy changes to predict whether reactions are spontaneous. Calculate standard free energy changes using standard free energies of formation. Predict the effect of temperature on spontaneity given DH and DS. Calculate DG under nonstandard conditions. Relate DG°and equilibrium constant (K). Review Chapter 5: energy, enthalpy, 1st law of thermo Thermodynamics: the science of heat and work Thermochemistry: the relationship between chemical reactions and energy changes Energy (E) The capacity to do work or to transfer heat. Work (w) The energy expended to move an object against an opposing force. w = F d Heat (q) Derived from the movements of atoms and molecules (including vibrations and rotations). Enthalpy (H) Enthalpy is the heat absorbed (or released) by a system during a constant-pressure process. 1 0th Law of Thermodynamics If A is in thermal equilibrium with B, and B is in thermal equilibrium with C, then C is also in thermal equilibrium with A.
    [Show full text]
  • CHEMISTRY (CHGN) - (2021-2022 Catalog) 1
    CHEMISTRY (CHGN) - (2021-2022 Catalog) 1 CHGN209. INTRODUCTION TO CHEMICAL THERMODYNAMICS. 3.0 CHEMISTRY (CHGN) Semester Hrs. (I, II, S) Introduction to the fundamental principles of classical CHGN111. INTRODUCTORY CHEMISTRY. 3.0 Semester Hrs. thermodynamics, with particular emphasis on chemical and phase (S) Introductory college chemistry. Elementary atomic structure and the equilibria. Volume-temperature-pressure relationships for solids, liquids, periodic chart, chemical bonding, chemical reactions and stoichiometry and gases; ideal and non-ideal gases. Introduction to kineticmolecular of chemical reactions, chemical equilibrium, thermochemistry, and theory of ideal gases and the Maxwell-Boltzmann distributions. Work, properties of gases. Must not be used for elective credit. Does not apply heat, and application of the First Law to closed systems, including toward undergraduate degree or g.p.a. 3 hours lecture and 3 hours lab; 3 chemical reactions. Entropy and the Second and Third Laws; Gibbs Free semester hours. Energy. Chemical equilibrium and the equilibrium constant; introduction to activities & fugacities. One- and two-component phase diagrams; Gibbs CHGN121. PRINCIPLES OF CHEMISTRY I. 4.0 Semester Hrs. Phase Rule. May not also receive credit for CBEN210 or GEGN330. Study of matter and energy based on atomic structure, correlation Prerequisites: CHGN121, CHGN122 or CHGN125, MATH111, MATH112, of properties of elements with position in periodic chart, chemical PHGN100. 3 hours lecture; 3 semester hours. bonding, geometry of molecules, phase changes, stoichiometry, solution chemistry, gas laws, and thermochemistry. 3 hours lecture, 3 hours lab; 4 CHGN221. ORGANIC CHEMISTRY I. 3.0 Semester Hrs. semester hours. Approved for Colorado Guaranteed General Education (I,S) Structure, properties, and reactions of the important classes of transfer.
    [Show full text]
  • Chemistry (CHEM) 1
    Chemistry (CHEM) 1 Chemistry (CHEM) CHEM 117. Chemical Concepts and Applications. 3 Credits. Introduction to general and organic chemistry, with applications drawn from the health, environmental, and materials sciences. Prereq or Coreq: MATH 103, MATH 104 or MATH 107 or Math placement. CHEM 117L. Chem Concepts and Applications Lab. 1 Credit. Introduction to general and organic chemistry, with applications drawn from the health, environmental, and materials sciences. Prereq or Coreq: MATH 103, MATH 104, MATH 107 or Math placement. CHEM 121L. General Chemistry I Laboratory. 1 Credit. Matter, measurement, atoms, ions, molecules, reactions, chemical calculations, thermochemistry, bonding, molecular geometry, periodicity, and gases. Prereq or Coreq: MATH 103 or MATH 107 or Math placement. CHEM 121. General Chemistry I. 3 Credits. Matter, measurement, atoms, ions, molecules, reactions, chemical calculations, thermochemistry, bonding, molecular geometry, periodicity, and gases. Prereq or Coreq: MATH 103 or MATH 107 or Math placement. CHEM 122L. General Chemistry II Laboratory. 1 Credit. Intermolecular forces, liquids, solids, kinetics, equilibria, acids and bases, solution chemistry, precipitation, thermodynamics, and electrochemistry. Prereq: CHEM 121L. CHEM 122. General Chemistry II. 3 Credits. Intermolecular forces, liquids, solids, kinetics, equilibria, acids and bases, solution chemistry, precipitation, thermodynamics, and electrochemistry. Prereq: CHEM 121. CHEM 140. Organic Chemical Concepts and Applications. 1 Credit. Introduction to organic chemistry for pre-nursing and other students who need to meet the prerequisite for CHEM 260. CHEM 150. Principles of Chemistry I. 3 Credits. Chemistry for students with good high school preparation in mathematics and science. Electronic structure, stoichiometry, molecular geometry, ionic and covalent bonding, energetics of chemical reactions, gases, transition metal chemistry.
    [Show full text]
  • 6. Chemical Thermodynamics and Energetics
    6. CHEMICAL THERMODYNAMICS AND ENERGETICS 1. THERMODYNAMICS 4.2 Intensive Properties It is the study of flow of energy. It encompasses the study of flow Such properties of a system which depends on concentration of heat as well as mass. and does not depend on the mass or the total number of particles in the system are categorized as Intensive properties. eg. Pressure, 2. THERMODYNAMICS TERMINOLOGY Density, Reractive Index. 5. STATE AND PATH FUNCTIONS 2.1 System Such thermodynamic functions which depend only on the initial and final states of the system and not on the path followed are The part of the Universe under observation is called system. called state functions eg. Internal energy, Enthalpy and the functions which depend on the path followed while changing 2.2 Surrounding from one state to the other are called path functions. eg. work heat. The part of the Universe not under observation is called Surrounding. 6. THERMODYNAMIC EQUILIBRIUM System + Surrounding = Universe A system is said to be under thermodynamic equilibrium when 2.3 Types of system none of the state variables are changing and it satisfies the three equilibriums. 2.3.1 Open System : A system in which both flow of mass and heat is possible. 6.1 Mechanical Equilibrium 2.3.2 Closed System : A system in which flow of heat is possible but flow of mass is not possible. There is no mechanical motion and the pressure and the volume of the system is not changing. 2.3.3 Isolated System : A system in which neither heat nor mass can flow in or out.
    [Show full text]
  • Lecture 1. Chemical Thermodynamics and Bioenergetics. Fundamentals of Thermochemistry
    Lecture 1. Chemical thermodynamics and bioenergetics. Fundamentals of thermochemistry. Lecture plan . 1. Types of thermodynamic systems. 2. Thermodynamics functions and parameters of system. 3. The first law of thermodynamics. Internal energy. Enthalpy. 4. Heat of isobaric and isochoric process. Standard heats of the substance formation and combustion. 5. Thermochemistry. Hess law. Thermochemical transformation. 6. Thermochemical calculation and their use for energetic characteristics of biochemical process. 7. Second law of thermodynamic. Entropy. Subject of thermodynamics All chemical reactions are accompanied by transformation of chemical energy to other forms of energy - thermal, electrical, mechanical, etc. Thermodynamics is the branch of physical science that studies all forms of energy and their mutual transformations; therefore it is sometimes called energetics. Bioenergetics is a field of thermodynamics that deals with biosystems. Classical thermodynamics is based on propositions which are confirmed by experiment and does not use knowledge about the molecular structure of substances.The energy of reactions is studied by the branch of thermodynamics which is called thermochemistry or chemical thermodynamics. In thermochemistry two types of chemical reactions are distinguished: exothermic (are accompanied by heat release) and endothermic (are accompanied by heat absorption). There are reactions (not so numerous), which are not accompanied by heat exchange. Chemical reactions can occur at a constant pressure (for example in an open flask) - these are isobaric processes, at a constant volume (in a closed flask or an autoclave) - these are isochoric processes, or at a constant temperature - these are isothermal processes (the names are derived from the Greek words isos - identical, baros - pressure, chorus - space, thermos - heat). Thermodynamics deals with the study of properties of various thermodynamic systems and processes occurring in them.
    [Show full text]
  • Modern Chemical Kinetics Modern Thermodynamics
    Computers Math. Applic. Vol. 17, No. 1-3, pp. 443--455, 1989 0097.4943/89 $3.00 + 0.00 Printed in Great Britain. All rights reserved Copyright © 1989 Pergamon Press pie CHEMICAL KINETICS AND THERMODYNAMICS A HISTORY OF THEIR RELATIONSHIP S. LENGYEL Central Research Institute for Chemistry, Hungarian Academy of Sciences, Budapest, P.O. Box 17, H-1525, Hungary Abstract--The history of the understanding of phenomenology and energeties of chemical reactions and their mutual relationship is given from a certain point of view. The differentiation of the ever growing knowledge on continua, where chemical reactions advance leading to the development of their thermody- namics and chemical kinetics as distinct science branches is considered. The integration of these two branches by a general variational principle of thermodynamics is carried out. The time evolution of chemical kinetic systems is studied in this integrated theory. The role of symmetry as an instrument of synthesis or integration is pointed out. 1. WHAT IS CHEMICAL AFFINITY? Modern chemical kinetics Modern chemical kinetics is a science describing and explaining chemical reactions as we understand them at present. In the beginning, it studied the dependence of the rates of the reactions proceeding in a system on the concentrations of the components then, also on other influences as temperature, electric field, radiation, etc. Later on, it turned to the molecular mechanism and special regimes, such as chain reactions, polymerization and degradation of polymers, flames, combustion, explosions, oscillation, atomic and molecular beam reactions, etc. Modern thermodynamics Modern thermodynamics is the thermodynamics of irreversible processes. It was developed on the basis of classical thermodynamics of equilibrium systems, called thermostatics by some authors.
    [Show full text]
  • Chemical Thermodynamics”, Chapter 18 from the Book Principles of General Chemistry (Index.Html) (V
    This is “Chemical Thermodynamics”, chapter 18 from the book Principles of General Chemistry (index.html) (v. 1.0). This book is licensed under a Creative Commons by-nc-sa 3.0 (http://creativecommons.org/licenses/by-nc-sa/ 3.0/) license. See the license for more details, but that basically means you can share this book as long as you credit the author (but see below), don't make money from it, and do make it available to everyone else under the same terms. This content was accessible as of December 29, 2012, and it was downloaded then by Andy Schmitz (http://lardbucket.org) in an effort to preserve the availability of this book. Normally, the author and publisher would be credited here. However, the publisher has asked for the customary Creative Commons attribution to the original publisher, authors, title, and book URI to be removed. Additionally, per the publisher's request, their name has been removed in some passages. More information is available on this project's attribution page (http://2012books.lardbucket.org/attribution.html?utm_source=header). For more information on the source of this book, or why it is available for free, please see the project's home page (http://2012books.lardbucket.org/). You can browse or download additional books there. i Chapter 18 Chemical Thermodynamics Chemical reactions obey two fundamental laws. The first of these, the law of conservation of mass, states that matter can be neither created nor destroyed. (For more information on matter, see Chapter 1 "Introduction to Chemistry".) The law of conservation of mass is the basis for all the stoichiometry and equilibrium calculations you have learned thus far in chemistry.
    [Show full text]
  • Organic Electrochemistry: Revised and Expanded
    Theoretical Calculation 6 of Reduction Potentials Junming Ho, Michelle L. Coote, Christopher J. Cramer, and Donald G. Truhlar Contents I.. Introduction...........................................................................................................................229 II.. Formal.Definitions,.Electrochemical.Concepts,.and.Basic.Considerations.......................... 231 A.. Ionization.Potentials.and.Electron.Affinities.................................................................231 B.. Standard.versus.Formal.Potentials................................................................................232 C.. Cyclic.Voltammetry.......................................................................................................233 D.. Effects.of.Protonation....................................................................................................234 E.. Reversible.and.Irreversible.Redox.Processes.................................................................235 F.. Liquid.Junction.Potentials..............................................................................................235 G.. Reference.Electrodes.....................................................................................................236 III.. Computation.of.Reduction.Potentials....................................................................................236 A.. Gas-Phase.Free.Energies.of.Reaction............................................................................237 1.. Gibbs.Free.Energy.and.the.Treatment.of.Nuclear.Motion......................................237
    [Show full text]
  • Chapter 9: Thermodynamic Processes and Thermochemistry Vankoppen Chem1b W03
    Chapter 9: Thermodynamic Processes and Thermochemistry VanKoppen Chem1B W03 In Chemistry 1A, we have been concerned with the quantitative description of reaction systems. We have expressed the tendency of reactants to be converted to products in terms of the equilibrium constant K for the reaction. Now we question why some reactions have large equilibrium constants while other reactions have small equilibrium constants. The goal of chemical thermodynamics is to predict what types of chemical and physical processes are possible and under what conditions. Thermodynamics can also suggest ways in which conditions can be changed to make a process possible. It can tell us if a process can occur, but it cannot tell us how fast it will occur. Thermodynamic reasoning is based on few apparently simple laws. These laws are not derived . Instead, they are generalizations that have been drawn from a vast number of observations of the way matter behaves. Note that thermodynamics is concerned only with the macroscopic properties of matter that, in principle, can be measured (such as temperature, pressure, volume, etc.). It does not depend on any particular model of the structure of matter such as atomic theory of matter. Chapter 9 covers the fundamental concepts of energy; the chemistry of energy production and exchange. First Law of Thermodynamics (the law of conservation of energy): The energy of the universe is constant. The First Law stated mathematically: E = q + w where DE = change in the system's internal energy, q = heat and w = work Our convention will be to take the system’s point of view : By definition: q > 0 => heat is added to the system q < 0 => heat is lost by the system w > 0 => work is done on the system w < 0 => work is done by the system DE > 0 => the system gains energy DE < 0 => the system loses energy The system's internal energy, E, can be changed by a flow of work, or heat or both work and heat.
    [Show full text]