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10 Cards in this Set
- Front
- Back
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What is the first law of thermodynamics?
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The total energy of a system and its surrounds is conserved. Energy is neither created nor destroyed.
Change in internal NRG (tri e) = Heat added (italics q) + work done on system (italics w) |
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What is the second law of thermodynamics?
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In any spontaneous process the entropy of the universe increases. Processes that are spontaneous in one direction are not spontaneous in the reverse direction.
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What is entropy (S)?
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Entropy (S) is a measure of the randomness of a system.
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What is the third law of thermodynamics?
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The entropy of a pure crystalline substance at absolute zero (0.0 K or -273 C) is zero.
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What is Hess's law?
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Hess's law states that, whether a reaction occurs in one step or in a series of steps, the change in enthalpy is an additive property.
Change in enthalpy (tri H) refers to the thermal NRG gained or lost when a change takes place under constant pressure. |
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What is Gibbs free energy (G)?
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Gibbs free energy is a thermodynamic state function that combines enthalpy and entropy. For a change occurring at a constant temperature and pressure, the formula is tri G = tri H - (temp times tri S)
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What is entropy (S)
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Entropy is a measure of the randomness of a system.
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What is enthalpy (H)?
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Enthalpy is a measure of the amount of heat.
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What does it mean when gibbs free energy (G) is postive/neutral/negative?
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If gibbs free energy (G) is negative, the reaction is spontaneous and forward, if it is zero, the reaction is at equilibrium, if it is positive, the reaction is nonspontaneous.
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What is the standard free-energy change?
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The standard free-energy change for a reaction equals the sum of the standard free-energy values per mole of each product, each multiplied by the corresponding coefficient in the balanced equation, minus the corresponding sum for the reactants.
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