Recent content by Sebi123

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    Why are Pokemon Exceptions considered code smell?

    When the call of the 3rd party library fails, catching the most general exception, try { // something that might fail for reasons I don't want to anticipate } catch (Exception ex) { // do something } is not a bad idea, unless your system should behave differently when different exceptions...
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    I Is the definition of a phase arbitrary?

    Ah, okay: Regarding a Pt-Cu-system: With specifying the concentrations in both phases as beeing pure phases I have already "used up" both of two degrees of freedom (f = 2-2+2=2 here) and T and p would need to take on very specific values to make the system consisting of two pure phases (if such...
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    I Is the definition of a phase arbitrary?

    .. because in the derivation of Gibbs rule I know the chemical potential of each component is set equal. µPt(in Pt bar) = µPt(in copper solution) (and the same of the copper solution). But there is not Pt in the copper solution, so this kind of derivation does not make sense, I guess.
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    I Is the definition of a phase arbitrary?

    The water-example might be nonsense. But there are equilibriums with completely different chemical compositions of the phases. For example, a platinum bar immersed in a copper solution. Does Gibbs phase rule (or classical thermodynamics at all) makes a statement about such situations?
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    I Is the definition of a phase arbitrary?

    Okay, I see my error in reasoning here, thanks. So, on small scales one has phase 1: H2O(g) + O2(g) phase 2: O2(g) phase 3: H2O(l) ? And this situation is not describable by Gibbs rule, because not each component is contained in each phase (no H2O in phase 2 and no O2 in phase 3)?
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    I Is the definition of a phase arbitrary?

    Thanks so far. For the simple example it's now becoming clearer. But to be sure to really understand it: For the system with H2O(l) in which O2(g)-bubbles are dissolved in contact with H2O(g) where also O2(g) exists: Are the phases phase 1: H2O(g) phase 2: O2(g) phase 3: H2O(l) or phase 1...
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    I Is the definition of a phase arbitrary?

    Do I need to check for all conceivable changes? Or is the selection of properties application dependend? In the example above: If I'm not interested in water being either gaseous or liquid, I would say I have only one "water-phase". I think Gibbs phase rule is applicable here, because µ(T,p)...
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    I Is the definition of a phase arbitrary?

    Oh, you mean each phase must include all components? Because of the derivation of Gibb's rule, which includes chemical potential functions µ(T,p,x1,...,xr-1) (with xi: mole fraction of component i) for each phase? If this example is not possible, how about a simplified version with H2O as the...
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    I Is the definition of a phase arbitrary?

    Gibbs phase rule says f = r-M+2 with f: thermodynamic degrees of freedom; r: number of components; M: number of phases I wonder whether the defintion of "phase" is restricted or almost arbitrary. For example, consider a system of H2O, O2 and H2 in a closed vessel. Let there be the contstraint...
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    Energy change of reservoir in reversible weight process

    Maybe I should rephrase the problem above. The short version is: In a reversible weight process, in which system A goes from state A1 to A2 and reservoir R from R1 to R2, the energy transferred to the weight is (W12AR→)rev = E1 - E2 + E1R - E2R = Ω1R - Ω2R This is equation 6.5 in section 6.6.4...
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    Energy change of reservoir in reversible weight process

    In what follows I refer to the ideas of "Thermodynamic: Foundations and Applications" by Gyftoploulos and Beretta. The abbreviated form of my question is: In a reversible weight process, Ω1R-Ω2R = E1 - E2 (see eqn. 6.18, p. 99) is transferred out of the composite of a system A and a reservoir R...
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    1st law, 2nd law, entropy by Gyftopoulos / Beretta is confusing

    The statistical approach might be simpler. I wonder why the book seems not to have received that attention I thought it would have after reading the preface, where the authors say they "... have composed an exposition of the foundations and the applications of thermodynamics that many...
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    1st law, 2nd law, entropy by Gyftopoulos / Beretta is confusing

    I find the basic idea behind the treatment of thermodynamics in the book so appealing, because everything there relies on lifting and lowering weights in a constant gravitational field. That is very intuitive and leads to an operational defintion of the terms "energy" and "entropy"...
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    1st law, 2nd law, entropy by Gyftopoulos / Beretta is confusing

    I'm reading Thermodynamics: Foundations and Applications by Gyftoploulos and Beretta, because the authors claim to give a presentation of classical thermodynamics without "... the lack of logical consistency and completeness in the many presentations of the foundations of thermodynamics" [from...
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