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Homework Help: Thermodynamics Question Calculating change in temperature

  1. Feb 3, 2015 #1
    1. The problem statement, all variables and given/known data
    50 moles of an ideal gas for which Cp= 5/2R and Cv=3/2R initially has a pressure of 1x10^5 Pa, and a volume of 1.0m^3. It undergoes a process where the pressure and volume both double while they stay proporitional to each other: P=constV. What is the change in temperature for this process?

    2. Relevant equations
    ΔU= Q-W
    ΔU= nCv(ΔT)

    3. The attempt at a solution
    So I started by trying to use PV=nRΔT and calculating T, however I wasnt successful. The answer in my book is in Kelvins, so I tried converting the temperature that I calculated to Kelvins, however it was still wrong.

    I'm thinking that I might need to take the integral: ∫ PVdv but im not sure if thats correct either.

    Can somone please help me out, It would be greatly appreciated.

    The correct answer is: 720K
    Last edited: Feb 3, 2015
  2. jcsd
  3. Feb 3, 2015 #2


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    The above equation is not correct. The ideal gas law is PV = nRT, not PV = nRΔT.

    From PV = nRT can you calculate the initial temperature? How about the final temperature?
  4. Feb 3, 2015 #3
    From the ideal gas law, what is the initial temperature? From the ideal gas law, what is the final temperature?

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