![]() ![]() Section 14-4: The Effect of Temperature on ΔG and the 0, the reaction is nonspontaneous at 75☌. Spontaneous reaction: Δ S rxn - Δ H rxn/T If we substitute for Δ S surroundings in the equation above, we obtain: Is related to Δ H rxn and the Kelvin temperature as Spontaneous reaction: Δ S universe = Δ S rxn Therefore, the Second Law of Thermodynamics can be expressed Includes everything but the reaction particles. We can consider the entropy change of the universe to be the sum of the entropyĬhange of the reaction plus the entropy change of the surroundings, which Increase as a result of a spontaneous process and, therefore, the entropyĬhange of the universe must be positive as a result of a spontaneous According to the Second Law of Thermodynamics, the entropy of the universe must Will continue to progress without outside intervention. Section 14-3: The Second Law of Thermodynamics and Using the standard entropies of the reactants and products as follows:Ĭalculate the value of ΔS° for the reaction N 2 (g) + 3 F 2īecause the moles of gas decrease during the reaction (1 + 3 → 2). Section 14-2: Calculating ΔS° Using StandardĮntropy change, ΔS°, for a reaction in the unit J/ mol More information is needed to determine the sign of ΔS. (d) 3 S (s) + 2 H 2O (g) → SO 2 (g) + 2 H 2SĪlthough the total moles decrease (3 + 2 → 1 + 2), Reaction, more information is generally needed to determine the sign of ΔS.įollowing processes generally occur with a decrease in entropy and, thus, a If the number of moles of gas does not change during a chemical Products on the right side is larger than the sum of coefficients of gasesĪmong the reactants on the left side). Number of moles of gas increases (the sum of coefficients of gases among the ![]() With an increase in entropy and, thus, a positive entropy change (ΔS): Indication of the level of disorder or chaos in a given system. Whereas thermochemistry focuses primarily on the heat involved in chemical reactions, thermodynamics explores the role of energy more broadly. Section 14-1: Predicting the Sign of the Entropy Section 14-5: Calculating ΔG° from Standard Gibbs Free Energies of Formation, ΔG f°Ĭhapter 14 Practice Exercises and Review Quizzes ![]() Section 14-4: The Effect of Temperature on ΔG and the Spontaneity of Reactions Section 14-3: The Second Law of Thermodynamics and Gibbs Free Energy Change, ΔG Section 14-2: Calculating ΔS° Using Standard Entropies, S° Section 14-1: Predicting the Sign of the Entropy Change, ΔS Andover's Chem 250: Introductory/Basic Chemistry Table of Contents ![]()
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