Ch 10 Entropy Free Energy Van Koppen Summary

# Ch 10 Entropy Free Energy Van Koppen Summary - Chapter 10:...

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Chapter 10: Spontaneity, Entropy and Free Energy VanKoppen First Law of Thermodynamics Energy is conserved. The energy of the universe is constant. E = q + w Energy of the system increases when heat is added to the system (q > 0) and when work is done on the system (w > 0). The First Law accounts for energy changes: How much energy is involved in a process? What is the direction of flow: into or out of the system? What is the final form of energy? Chapter 10: Focuses on why a process occurs in a given direction (the first law does not tell us why). A spontaneous process is a process which occurs without outside intervention. For example, a gas expands to fill an entire container spontaneously. The gas molecules in a container will not all move to one side of the container spontaneously. Why not? A spontaneous process may be fast or slow. Thermodynamics tells us the direction in which a process will occur but says nothing about the speed (rate) of a process. Chemical kinetics (Chapter 15) is concerned with the rate of reaction. Entropy is the driving force for all spontaneous processes. Natural Progression: Low Entropy ——> High Entropy Entropy (S) corresponds to the number of arrangements (positions and/or energy levels) that are available to a system in a given state. It is closely related to probability. The more ways a particular state can be achieved, the greater is the likelihood (probability) that state will occur. Nature spontaneously proceeds towards the states that have the highest probabilities of existing. Entropy is also related to the dispersion of energy. The greater the dispersion of energy the greater the entropy. Generally: S solid < S liquid << S gas Because one mole of gas will occupy a greater volume then one mole of liquid or solid, the number of positions available to the gas molecules is greater and the entropy of a gas is therefore greater. When the gas expands to fill a larger volume, its energy is more dispersed and thus the entropy of the gas is greater. For a

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## Ch 10 Entropy Free Energy Van Koppen Summary - Chapter 10:...

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