CH3205: Thermodynamics and Kinetics
|School||Cardiff School of Chemistry|
|External Subject Code||F170|
|Number of Credits||20|
|Language of Delivery||English|
|Module Leader||Dr Alison Paul|
Outline Description of Module
This module explores fundamental concepts in thermodynamics and kinetics, including an introduction to statistical mechanical approaches. Building on the introduction of enthalpy, entropy and free energy in the module CH3101, the relationship between free energy and different types of equilibrium constants will be explored. Statistical mechanical definitions of simple concepts in thermodynamics and kinetics will be developed. The key topics of electrochemistry and colloid science will then be used to exemplify the relationship between energy and structure. Experimental routes to obtaining critical thermodynamic quantities are explored in the accompanying laboratory classes. The kinetics aspect of this module will build on introductory material (Yr 1) to the level where complex experimental kinetics may be treated mathematically, focusing on complex sequences of elementary reactions, competing reactions and chain reactions, together with aspects of the kinetics of surface processes such as catalysis and corrosion.
On completion of the module a student should be able to
Knowledge and Understanding
- show a detailed understanding of the laws of thermodynamics;
- demonstrate an understanding of the relationship between equilibrium constants and free energy changes;
- define chemical potential and describe how this varies with changing system composition;
- show how kinetic theory can be extended to chemical reactions using the simple assumptions of collision theory;
- discuss the limitations of collision theory in describing the gas phase reactions of molecules;
- demonstrate an understanding of the link between statistical models and thermodynamic quantities;
- illustrate how the Boltzmann distribution arises from the statistical definitions of internal energy, entropy;
- appreciate how a statistical mechanics approach provides an alternative to collision theory;
- define microstates and link them to thermodynamic observables for a given system;
- illustrate how the Boltzmann distribution arises from the statistical definitions of internal energy and entropy;
- explain the concept of activity, describe ionic strength, ideal and non-ideal electrolytes and how solution non-ideality influences solubility products;
- demonstrate understanding of the precepts underlying the Debye-Hückel limiting law;
- recall and use the Nernst equation, determine electrode polarities of an electrochemical cell and calculate standard electrode potentials from tabulated data;
- calculate cell EMF and hence thermodynamic parameters including Gibbs free energy;
- demonstrate understanding of surfactant adsorption and aggregation behaviour in aqueous solution, and the thermodynamic driving forces for this;
- name and describe thermodynamic models for surfactant micellisation based on chemical potentials and equilibrium constants;
- describe the origins of key contributions to the Gibbs free energy change for various dispersion processes;
- sketch and describe potential energy diagrams for various types of colloidal particle dispersion;
- understand the relationships between empirical reaction rates and reaction mechanisms, and describe the concept of the rate determining step;
- employ the steady-state and equilibrium approximations to analyse kinetic data;
- describe the steps involved in surface adsorption;
- recall the assumptions of the Langmuir and BET isotherms;
- describe modern experimental methods of studying reaction kinetics.
- understand the use of theoretical models to explain the kinetics and thermodynamics observed in real systems;
- design practical experiments based on equilibrium systems to obtain key thermodynamic parameters;
- design practical experiments to investigate the kinetics of complex reactions;
- appreciate the design criteria behind the formulation of common colloidal products.
How the module will be delivered
The module will be delivered in 33 hours of lectures (33 x 1 hr), 4 hours of tutorials, 10 hours of assessed (formative and summative) workshops and 27 hours of laboratory work.
Skills that will be practised and developed
Statistical analysis of experimental data, including errors, accuracy and precision.
Awareness and importance of COSHH, completion of associated documents.
How the module will be assessed
A written exam (3 h) will test the student’s knowledge and understanding as elaborated under the learning outcomes. The coursework (workshops and tutorials) will allow the student to demonstrate his/her ability to judge and critically review relevant information. Practical skills will be assessed via a series of laboratory-based exercises.
|Written Assessment||8||Autumn Semester Workshops||N/A|
|Online Examination - Spring Semester||60||Thermodynamics And Kinetics||3|
|Written Assessment||8||Spring Semester Workshops||N/A|
|Written Assessment||2||Autumn Semester Tutorials||N/A|
|Practical-Based Assessment||10||Spring Semester Practical||N/A|
|Written Assessment||2||Spring Semester Tutorials||N/A|
|Practical-Based Assessment||10||Autumn Semester Practical||N/A|
Lecture material will be delivered in the following sections. Each section will have associated assessed workshop and tutorial material.
1. Concepts in thermodynamics (4L)
Thermodynamic quantities such as ∆G, ∆H, ∆S. Revision of first law of thermodynamics (summary), second law of thermodynamics (entropy, direction of spontaneous change, absolute entropies, entropy of an ideal gas, and the third law).
Equilibrium thermodynamics: relationships between equilibrium, free energy and chemical potential: Gibbs free energy of formation, extensivity and partial molar quantities, solubility products.
Helmholtz and Gibbs energies, standard molar Gibbs energies.
Basic thermodynamics of gases, liquids and solids. Surface tension.
2. Introduction to statistical mechanics (6L)
A brief review of the kinetic theory of gases and its extension to collision theory of reaction rates.
Failures of the collision theory illustrated with examples from gas kinetics.
Development of statistical mechanics starting from a conceptual definition of a microstate, simple examples of microstate counting.
Statistical definition of internal energy, entropy and chemical potential.
Derivation of the Boltzmann distribution.
3. Applied thermodynamics and equilibria:Electrochemistry (6L)
Links between Gibbs free energy and electrical work for reversible cells. Gibbs-Helmholtz equation and its application to electrochemical cells.
Solutions and solubility products. Susceptibility to corrosion from measurements of EMF.
Concept of activity. Ionic strength principle. Debye-Huckel limiting law.
Redox potentials. Electrochemical potentials – relationships to chemical potentials. Nernst Equation
The Boltzmann formula for entropy and configurational entropy
4. Applied thermodynamics and equilibria: Colloid science (6L)
Introduction to colloidal systems: surfactants, micelles, microemulsions and particle suspensions. Effect of surfactants on surface tension.
Thermodynamic models of micellisation; relationship between DG and the critical micelle concentration – chemical potentials and equilibrium constants. Factor contributing to free energy change for micellisation.
Stability in liquid/liquid dispersions – contributions to free energy change for dispersion.
Stability in solid/liquid dispersions – interaction energies and potential energy diagrams.
5. Solution kinetics (7L)
Derivation of simple rate equations for complex reactions (consecutive, parallel, reversible unimolecular processes),
Approximate solutions to these via the steady-state and equilibrium approximations.
Enzyme kinetics (including various forms of inhibition),
Chain reactions (branching chains, explosions, oscillating reactions).
Interpretation of rate constants in terms of diffusion- or activation-controlled reactions.
Transition state theory, from the standpoint of equilibrium constants.
6. Surface kinetics (3L)
The kinetics of reactions at surfaces will be introduced in terms of rates of adsorption & desorption, precursor states and the common mechanisms (Langmuir-Hinshelwood and Eley-Rideal). Kinetic methods of studying surface reactions will be highlighted.
Laboratory sessions will be divided into two parts, four sessions in Autumn, five sessions in Spring. Each part is designed to reflect the theory of kinetics and thermodynamics presented in lectures.
Thermodynamics and Electrochemistry (13 hrs, Autumn semester)
Measurement of standard enthalpies of formation and reaction stoichiometries via calorimetry
Measurement of equilibrium constants using a spectroscopic method.
Measurement of standard electrochemical potentials.
Measurement of Gibbs free energies, entropies and enthalpies for a reversible electrochemical cell.
Kinetics and Equilibria (14 hrs, Spring semester)
Computer simulation and analysis of reactivity data,
Simple characterisation of reaction rates (pH, Uv-vis),
Competition in reactions (enzyme kinetics)
Essential Reading and Resource List
An indicative reading list will be included in the Course Handbook.
Background Reading and Resource List
An indicative reading list will be included in the Course Handbook.