![]() The hot object is comprised of particles A and B and initially contains both energy units. ![]() Consider a system consisting of two objects, each containing two particles, and two units of thermal energy (represented as “*”) in Figure 12.8. Conversely, processes that reduce the number of microstates, W f W i, the expansion process involves an increase in entropy (Δ S > 0) and is spontaneous.Ī similar approach may be used to describe the spontaneous flow of heat. Δ S = S f − S i = k ln W f − k ln W i = k ln W f W i Δ S = S f − S i = k ln W f − k ln W i = k ln W f W iįor processes involving an increase in the number of microstates, W f > W i, the entropy of the system increases and Δ S > 0. In 1865, Clausius named this property entropy ( S) and defined its change for any process as the following: Similar to other thermodynamic properties, this new quantity is a state function, so its change depends only upon the initial and final states of a system. Figure 12.6 (a) Nicholas Léonard Sadi Carnot’s research into steam-powered machinery and (b) Rudolf Clausius’s later study of those findings led to groundbreaking discoveries about spontaneous heat flow processes. Note that the idea of a reversible process is a formalism required to support the development of various thermodynamic concepts no real processes are truly reversible, rather they are classified as irreversible. In thermodynamics, a reversible process is one that takes place at such a slow rate that it is always at equilibrium and its direction can be changed (it can be “reversed”) by an infinitesimally small change in some condition. This new property was expressed as the ratio of the reversible heat ( q rev) and the kelvin temperature ( T). A later review of Carnot’s findings by Rudolf Clausius introduced a new thermodynamic property that relates the spontaneous heat flow accompanying a process to the temperature at which the process takes place. In 1824, at the age of 28, Nicolas Léonard Sadi Carnot ( Figure 12.6) published the results of an extensive study regarding the efficiency of steam heat engines. Predict the sign of the entropy change for chemical and physical processes.Explain the relationship between entropy and the number of microstates. ![]() Appendix L: Standard Electrode (Half-Cell) Potentialsīy the end of this section, you will be able to:.Appendix K: Formation Constants for Complex Ions.Appendix I: Ionization Constants of Weak Bases.Appendix H: Ionization Constants of Weak Acids.Appendix G: Standard Thermodynamic Properties for Selected Substances.Appendix F: Composition of Commercial Acids and Bases.Appendix D: Fundamental Physical Constants.Appendix C: Units and Conversion Factors.Second Law of Thermodynamics and Gibbs Free Energy.Application: Precipitation and Dissolution.Shifting Equilibria: LeChatelier’s Principle.Chemical Equilibria and Applications Toggle Dropdown Collision Theory and Factors Affecting Reaction Rates.Solutions and Colligative Properties Toggle Dropdown Liquids, Solids, and Modern Materials Toggle Dropdown Chemical Bonding and Molecular Geometry Toggle Dropdown Thermochemical Guidelines, Enthalpy of Formation and Hess's Law.Solution Stoichiometry and Combustion Analysis.Writing and Balancing Chemical Equations.Stoichiometry of Chemical Reactions Toggle Dropdown Determining Empirical and Molecular Formulas.Composition of Substances and Solutions Toggle Dropdown Molecular and Ionic Compounds and Their Nomenclature.Early Ideas and Evolution of Atomic Theory.Atoms, Molecules and Ions Toggle Dropdown Measurements and Uncertainty in Measurement. ![]()
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