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13 Cards in this Set
- Front
- Back
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First law of thermodynamics
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energy can be neither created or destroyed
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Second law of thermodynamics
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-for any spontaneous process, the entropy of the universe increases (ΔSuniv > 0)
-for every energy transaction, some energy is lost to the surroundings; this lost energy is nature's heat tax |
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Thermodynamics
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the study of the spontaneity of reactions
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Entropy (S)
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-proportional to the number of energetically equivalent ways in which the components of a system can be arranged
-a measure of energy dispersal per unit temperature |
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Enthalpy (H)
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-the sum of the internal energy of a system and the product of its pressure and volume
-the energy associated with the breaking and forming of bonds in a chemical reaction |
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For a process to be spontaneous
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the total entropy of the universe (system + surroundings) must increase
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The entropy of the surroundings increases when
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the change in enthalpy of the system (ΔHsys) is negative (for exothermic reactions)
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The change in entropy of the surroundings for a given ΔHsys depends inversely on
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temperature-- the greater the temperature, the lower the magnitude of ΔSsurr
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Gibbs free energy (G)
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-a thermodynamic function that is proportional to the negative of the change in the entropy of the universe
-ΔG represents a spontaneous reaction +ΔG represents a nonspontaneous reaction |
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Third law of thermodynamics
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the entropy of a perfect crystal at absolute zero (0K) is zero
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standard free energy change, ΔG°rxn
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the change in free energy for a process when all reactants and products are in their standard states
-ΔG°rxn representss the theoretical amount of energy available to do work +ΔG°rxn represents the minimum amount of energy required to make a nonspontaneous process occur |
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free energy formation, ΔG°f
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the change in free energy when 1 mol of a compound forms from its constituent elements in their standard states
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The more negative the free energy change (i.e., the more spontaneous the reaction)
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the larger the equilibrium constant
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