[...]... rule in Chapter 4 Thermodynamic variables In thermodynamics the state of a system is specified in terms of macroscopic state variables such as volume, V, temperature, T, pressure, p, and the number of moles of the chemical constituents i, ni The laws of thermodynamics are founded on the concepts of internal energy (U), and entropy (S), which are functions of the state variables Thermodynamic variables... a preferred set of orientations Strictly spoken, only ergodic states can be treated in terms of classical thermodynamics 1.2 The first law of thermodynamics Conservation of energy The first law of thermodynamics may be expressed as: Whenever any process occurs, the sum of all changes in energy, taken over all the systems participating in the process, is zero The important consequence of the first law... seen by consideration of the enthalpies of formation of these ternary oxides from their binary constituent oxides, often termed the o standard molar enthalpy of formation from oxides, D f ,ox H m , which correspond o to D r H m for the reaction SiO2 (s) + Al2O3 (s) = Al2SiO5 (s) (1.21) 1.2 The first law of thermodynamics 11 Table 1.4 The enthalpy of formation of the three polymorphs of Al2SiO5, kyanite,... the standard entropy of transition derived from the standard enthalpy of melting The third law of thermodynamics is thereby confirmed The entropies of both modifications are zero at 0 K The Maxwell relations Maxwell used the mathematical properties of state functions to derive a set of useful relationships These are often referred to as the Maxwell relations Recall the first law of thermodynamics, which... The different homogeneous phases are readily distinguished from each Chemical Thermodynamics of Materials by Svein Stølen and Tor Grande © 2004 John Wiley & Sons, Ltd ISBN 0 471 492320 2 1 2 1 Thermodynamic foundations other macroscopically and the thermodynamics of the system can be treated based on the sum of the thermodynamics of each single homogeneous phase In colloids, on the other hand, the... subtraction of the standard molar enthalpy of formation of the binary oxides, since standard enthalpies of individual reactions can be combined to obtain the standard enthalpy of another reaction Thus, o o o D f,ox H m ( Al2 SiO 5 ) = D f H m ( Al2 SiO 5 ) - D f H m ( Al2 O 3 ) (1.22) o - D f H m ( SiO2 ) This use of the first law of thermodynamics is called Hess’s law: The standard enthalpy of an overall... enthalpy of the reactants i and products j (vi and vj are the stoichiometric coefficients of reactants and products in the chemical reaction) o Of particular importance is the standard molar enthalpy of formation, D f H m , which corresponds to the standard reaction enthalpy for the formation of one mole of a compound from its elements in their standard states The standard enthalpies of formation of three... Definition of the chemical potential A homogeneous open system consists of a single phase and allows mass transfer across its boundaries The thermodynamic functions depend not only on temperature and pressure but also on the variables necessary to describe the size of the system and its composition The Gibbs energy of the system is therefore a function of T, p and the number of moles of the chemical. .. energy of the system doing the work decreases In general, dw is written in the form (intensive variable)◊d(extensive variable) or as a product of a force times a displacement of some kind Several types of work terms may be involved in a single thermodynamic system, and electrical, mechanical, magnetic and gravitational fields are of special importance in certain applications of materials A number of types... dimensions of the homogeneous regions are about 1 mm or less in size The thermodynamics of surfaces will be considered in Chapter 6 A homogeneous system – solid, liquid or gas – is called a solution if the composition of the system can be varied The components of the solution are the substances of fixed composition that can be mixed in varying amounts to form the solution The choice of the components is often . of Science and Technology, Norway with a chapter on Thermodynamics and Materials Modelling by Neil L. Allan School of Chemistry, Bristol University, UK Chemical Thermodynamics of Materials Chemical. w0 h0" alt="" Chemical Thermodynamics of Materials Macroscopic and Microscopic Aspects Svein Stølen Department of Chemistry, University of Oslo, Norway Tor Grande Department of Materials Technology,. set of orientations. Strictly spoken, only ergodic states can be treated in terms of classical thermodynamics. 1.2 The first law of thermodynamics Conservation of energy The first law of thermodynamics