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Chemistry: Thermodynamics & Thermochemistry Flashcards

7 cards from real AP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. What is the second law of thermodynamics?

    Answer: Entropy of the universe increases in spontaneous processes

    The second law states the total entropy of the universe increases for any spontaneous process.

  2. If a reaction releases 100 kJ and the surroundings gain that heat, what is ΔH_surroundings?

    Answer: +100 kJ

    Heat released by the system is gained by the surroundings, so ΔH_surroundings is +100 kJ.

  3. Which has the greatest standard molar entropy?

    Answer: H₂O(g)

    Gaseous water has the most disorder and thus the highest entropy.

  4. Using ΔH°rxn = ΣΔHf(products) − ΣΔHf(reactants), the formula computes what?

    Answer: Standard enthalpy of reaction

    This formula gives the standard enthalpy change of a reaction from formation enthalpies.

  5. At equilibrium, what is the value of ΔG?

    Answer: Zero

    At equilibrium there is no net driving force, so ΔG = 0.

  6. Coffee-cup calorimetry typically measures heat at constant what?

    Answer: Pressure

    An open coffee-cup calorimeter operates at constant atmospheric pressure, measuring ΔH.

  7. How is the relationship between ΔG° and K expressed?

    Answer: ΔG° = −RT ln K

    The standard free energy relates to the equilibrium constant by ΔG° = −RT ln K.