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2007. 5. r ész

2007. 5. r ész. Termodinamikai alapok Entalpia: H = U + pV; reakcióhő nyitott edényben, vagyis ha p = const. Entalpiadiagramok:. A folyamatok iránya: e ntr ópia. Wikipedia Microscopic definition of entropy (statistical mechanics)

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2007. 5. r ész

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  1. 2007. 5. rész

  2. Termodinamikai alapok Entalpia: H = U + pV; reakcióhő nyitott edényben, vagyis ha p = const. Entalpiadiagramok:

  3. A folyamatok iránya: entrópia

  4. Wikipedia • Microscopic definition of entropy (statistical mechanics) • In statistical thermodynamics the entropy is defined as the number of microscopic configurations that result in the observed macroscopic description of the thermodynamic system: • S = kB ln • where • kB is Boltzmann’s constant 1.38066×10−23 J K−1 and  • is the number of microstates corresponding to the observed thermodynamic macrostate.

  5. Szabadentalpia: G= H – TS; minimuma definiálja az EGYENSÚLYT

  6. Elektrokémia Galváncellák Fémlemez vízbe mártva: bizonyos tendenciával pozitív ionok mennek az oldatba; egy idő után a lemez negatív töltése már nem engedi, dinamikus egyensúly alakul ki. Az ábra azt illusztrálja, hogy a Mg nagyobb hajlammal oldódik be ...

  7. Elektródpotenciál: a hidrogénelektróddal szemben mért e.m.e.

  8. Egy üzemanyag-cella

  9. Elektrolízis: réz raffinálása

  10. Reakciókinetika: reakciók sebessége, mechanizmusa

  11. Ütközési elmélet, az Arrhenius-egyenlet. k = A exp (-Ea/RT)

  12. Hidrogénezés 2. http://www.chemgapedia.de/vsengine/vlu/vsc/en/ch/12/oc/vlu_organik/alkene/hydrierung.vlu/Page/vsc/en/ch/1 Details of the mechanism of catalytic hydrogenation are not known. Probably, both hydrogen and alkene are bound to the surface of the catalyst activating the π bond of the alkene as well as the σ bond of the hydrogen. The alkane product only leaves the surface of the catalyst after the transfer of hydrogen (deuterium) atoms to the alkene is completed. Fig.3Mechanism of catalytic hydrogenation The reaction rate of hydrogenation depends on the degree of substitution at the double bond. Higher-substituted alkenes show a lower reaction rate than less substituted. This fact can be explained by larger steric hindrance as well as better stabilization of the π bond in higher-substituted alkenes. Therefore, selective hydrogenation of differently substituted double bonds is often possible. For an overview of alkene hydrogenation click here.

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