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Homework Help: Pressure from compression

  1. Jun 3, 2010 #1
    a sample of an idel monotomic gas is intially at a pressure 1.6*10^4Pa and undergoes an adiabatic compression which halves the volume. What is the final pressure?

    ive been trying to find a way of useing the equation W=-P[tex]\Delta[/tex]V but am starting to think this is the wrong one as i cant see how i can use it.

    any suggestions?
     
  2. jcsd
  3. Jun 3, 2010 #2

    ehild

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    Find the relation between pressure and volume of an ideal gas during an adiabatic process.

    ehild
     
  4. Jun 3, 2010 #3
    sorry i cant see it :(,

    i can only see that p*V= a constant but not sure how to use that here!

    am i way off track?
     
  5. Jun 3, 2010 #4

    ehild

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  6. Jun 3, 2010 #5
    im still unclear on the relationship after reading that
     
  7. Jun 3, 2010 #6

    rock.freak667

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    Last edited by a moderator: Apr 25, 2017
  8. Jun 3, 2010 #7

    ehild

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    The mathematical equation for an ideal fluid undergoing a reversible (i.e., no entropy generation) adiabatic process is

    [tex] P V^{\gamma} = \operatorname{constant} \qquad [/tex]

    where P is pressure, V is volume, and

    [tex] \gamma = {C_{P} \over C_{V}} = \frac{\alpha + 1}{\alpha}[/tex],

    CP being the specific heat for constant pressure, CV being the specific heat for constant volume, γ is the adiabatic index, and α is the number of degrees of freedom divided by 2 (3/2 for monatomic gas, 5/2 for diatomic gas).

    ehild
     
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