CHEM 102 1nd Edition Lecture 8 Outline of Previous Lecture I. Enthalpy EquationsII. Thermodynamics DefinitionsIII. Natural Tendencies for DisorderIV. EntropyV. Example of EntropyOutline of Current LectureI. Example of DisorderII. Third Law of ThermodynamicsIII. Example of EntropyIV. Example of Enthalpy and EntropyCurrent LectureI. Example of Disorder- Which has a decrease in disorder?o 1 mol CH4 in 1 L flask compared to 2 L flask (volume is increasing so disorder increases)o CO2 (g) CO2 (aq) **** (disorder increase because the compound goes from gas to a more disciplined state)o CuCl2 (s) Cu2+ + 2 Cl- (the number of atoms increase because you have 1mol on the left compared to 3 mols on the right; as number of atoms increases, the entropy increase)o CaO compared to KCl (KCl is held looser together than that of CaO)II. Third Law of Thermodynamics- Entropy of a pure substance at absolute zero is 0.- Sperfect crystal is 0 at 0 K- There is a table of absolute entropies under standard conditionsIII. Example of Entropy- Entropy of 4Fe(s) +3O2(g) 2FeO2O3 (g)o Increaseo Decrease **** (More bonds are formed between atoms)o Remains the sameo Cannot determine from conditionsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.IV. Example of Enthalpy and Entropy- If a reaction is Exothermic, then the entropy of the surroundings is:o Increased **** (if more heat is put into the surroundings, then the molecules will heat up causing more disorder because they are moving faster)o Decreasedo The sameo More information is
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