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Homework Help: Isobaric Process

  1. Jun 10, 2010 #1
    1. The problem statement, all variables and given/known data

    Pf
    429

    Q
    -754

    ΔU
    819

    The table above shows the measurements taken while an ideal gas underwent an ISOBARIC process. Fill in the appropriate values for the table below.

    ΔP=?



    2. Relevant equations

    Q= ΔU+W=ΔU=PΔV

    3. The attempt at a solution

    I dont know how to go about solving this
     
  2. jcsd
  3. Jun 10, 2010 #2

    rock.freak667

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    For an isobaric process, what is constant? Hence what is ΔP ?
     
  4. Jun 10, 2010 #3

    vela

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    Do you know what isobaric means? If not, look it up.
     
  5. Jun 11, 2010 #4
    isobaric means same pressure

    but i tried 429 and that didnt work

    Is the difference in pressure 0? so 0 would be delta p?
     
  6. Jun 11, 2010 #5

    rock.freak667

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    Right so if it means the same pressure, then the final pressure and the initial pressure are the same. So the change in pressure would be 0.
     
  7. Jun 11, 2010 #6

    vela

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    It sounds like you're just guessing. You need to understand that the equations have meanings and the quantities that appear in them have precise definitions. If you don't know what ΔP represents, the first thing you need to do is figure that out.

    In this case, ΔP=Pf-Pi represents the change in pressure between the initial and final states, so your answer of 429 (units?) would mean that the pressure increased by that amount. Clearly, this doesn't meet the condition of an isobaric process, where the pressure is, by definition, constant. Since the pressure is constant, you know that Pi=Pf, so ΔP=0.
     
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