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Thermodynamic temperature derivation

  1. Dec 30, 2014 #1


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    In deriving thermodynamic temperature scale, it uses the concept that heat transfer between two reservoirs is the function of the reservoirs' temperatures. i.e. Q1/Q2=Φ(T1,T2). And then further express that Φ(T1,T2)=ψ(T1)/ψ(T2).

    I have two questions, 1. Is it a hidden assumption that the function Φ doesn't change its form for different temperatures? i.e. for different reservoirs we just plug in different temperatures Φ(T1,T2), Φ(T3,T4) but it can never be some other functions for different temperatures. Why?

    2. Why Φ(T1,T2) can be expressed as ψ(T1)/ψ(T2)? Any underlying assumptions?
    Last edited: Dec 30, 2014
  2. jcsd
  3. Jan 2, 2015 #2
    Your question doesn't make any sense. The fact that it depends on temperatures means that Φ can change its value for different temperatures. It can.
    My understanding is this is an underlying assumption, at least in this presentation of the material.
  4. Jan 2, 2015 #3
    See Section 5.3 in Introduction to Chemical Engineering Thermodynamics by Smith and Van Ness.

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