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9 Thermodynamics 2 - Penn State Universitycourses.chem.psu.edu/chem112/Summer/Lecture Notes/9_Thermodynamics...RX-Z+,-%5m%3H1%:7:31=%$"#$%Z#-%/ ... @AB%BB)AA
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!Gf° is the :3829849%m411%1214n7%5m%m54=83;52!!Gf° Free energy change in forming one mole of a compound from its elements each in their standard states.
For a spontaneous process, !G = Wmax = The maximum work that can be obtained from a process at constant T and P. For a non-spontaneous process, !G = Wmin = The minimum work that must be done to make a process go at constant T and P.
What is “free” about Free Energy? !G is how much work can be done by a process and is the portion of the energy change of a spontaneous reaction that is free to do useful work. But in actuality, not all of this “free energy” will be able to be used to do work. Some the energy enters the environment as heat. =>%?,@#-% A"(B%CCD% D]%
RELATIONSHIP BETWEEN !G AND WORK
Calculate the maximum energy available from the oxidation of octane at 25 oC and 1 atm.
1) Combustion (burning) = exo 2) Breaking multiple bonds = endo 3) Forming bonds = exo 4) Phase changes s M ! M g = endo 5) Opposite processes (g #% ! M s) = exo 6) Measured T #% OR heat given off = exo 7) Measured T $% OR heat added = endo
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!S is positive (disorder increases) when: 1) # molecules of gas #% during a reaction 2) Phase changes%s M% ! M% g 3) Solid dissolves in solution 4) # particles #% during a reaction 5) # atoms in a molecule is larger 6) T increases 7) V increases
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