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Homework Help: Thermodynamic Processes

  1. Feb 6, 2010 #1
    1. The problem statement, all variables and given/known data

    A cylinder with a piston contains 0.250 moles of oxygen at 2.40 * 10^5 Pa and 355K. The oxygen may be treated as an ideal gas. The gas first expands isobarically to twice its original volume. It is then compressed isothermally back to its original volume, and finally it is cooled isochorically to its original pressure

    Compute the temperature during the isothermal compression.
    Compute the maximum pressure.
    Compute the total work done by the piston on the gas during the series of processes.

    2. Relevant equations

    3. The attempt at a solution

    For the first question Compute the temperature during the isothermal compression, I really have no idea how to start. I've been searching through my lecture notes and text book for an hour and I just can not figure out a strategy to calculate it.

    I've calculated the maximum pressure because it's simply double the initial, and if I could just solve for the T in part 1 I could calculate the work done. Very frustrated please help!
  2. jcsd
  3. Feb 6, 2010 #2
    Use the ideal gas equation

    To find the work you need only information about the volume and pressure
  4. Feb 6, 2010 #3
    If you remember that isobaric means the pressure remains constant you can find the temperature during the expansion. Then during the compression, the problem says the temperature does not change because it is an isothermic compression.

    Find the temperature from the ideal gas equation: [tex]\ PV=nRT [/tex]

    This also may help: [tex]\ P_1V_1 / P_2V_2 = T_1 / T_2 [/tex] (if the pressure is the same, what does this simplify to?)
  5. Feb 6, 2010 #4
    Thanks guys I have solved the question!
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