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# chap16notes - Chapter 16 - Spontaneity, Entropy, and Free...

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1 Chapter 16 - Spontaneity, Entropy, and Free Energy 16.1 Spontaneous Processes and Entropy A. First Law 1. "Energy can neither be created nor destroyed" 2. The energy of the universe is constant B. Spontaneous Processes 1. Processes that occur without outside intervention 2. Spontaneous processes may be fast or slow a. Many forms of combustion are fast b. Conversion of diamond to graphite is slow C. Entropy (S) 1. A measure of the randomness or disorder 2. The driving force for a spontaneous process is an increase in the entropy of the universe 3. Entropy is a thermodynamic function describing the number of arrangements that are available to a system a. Nature proceeds toward the states that have the highest probabilities of existing D. Positional Entropy 1. The probability of occurrence of a particular state depends on the number of ways (microstates) in which that arrangement can be achieved S solid < S liquid << S gas 16.2 Entropy and the Second Law of Thermodynamics A. Second Law of Thermodynamics 1. "In any spontaneous process there is always an increase in the entropy of the universe" 2. "The entropy of the universe is increasing" 3. For a given change to be spontaneous, S univ must be positive S univ = S sys + S surr 16.3 The Effect of Temperature on Spontaneity A. Direction of Heat Flow 1. Entropy changes in the surroundings are primarily determined by heat flow a. Exothermic reactions in a system at constant temperature increase the entropy of surroundings b. Endothermic reactions in a system at constant temperature decrease

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## This note was uploaded on 09/28/2009 for the course CHEM 102 taught by Professor Freeman during the Spring '08 term at South Carolina.

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chap16notes - Chapter 16 - Spontaneity, Entropy, and Free...

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