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  1. #1 gas laws 
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    Hi,

    studying an old text by one C J Hall

    any help with this derivation would be most appreciated

    "
    From Pv^n =C ....

    (P^(1/n))(T/P) = C
    or
    TP^((1-n)/n)
    "
    P=Pressure
    v=Volume
    T=Temperature
    n is a characteristic of the process

    Cheers


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  3. #2  
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    Uh ... no,
    n is a characteristis of the process, for example n = 1.4 for a reversible adiabatic process


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  4. #3  
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    Quote Originally Posted by vette72
    Uh ... no,
    n is a characteristis of the process, for example n = 1.4 for a reversible adiabatic process
    I therefore suspect that you are in fact dealing with an isentropic process in which case what you are calling "n" is the ratio of specific heats. That quantity depends on the gas but is 1.4 for a diatomic gas.

    http://en.wikipedia.org/wiki/Heat_capacity_ratio

    http://en.wikipedia.org/wiki/Adiabatic_process
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  5. #4  
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    In the specific case of n=1.4 we are definately dealing with an isentropic process.

    Returning to the original question which was the derivation of another formula from PV^n=C.

    "
    From Pv^n =C ....

    (P^(1/n))(T/P) = C

    or

    TP^((1-n)/n) = C
    "

    I do not think the value of n will affect the derivation of the formula.
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  6. #5  
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    Quote Originally Posted by vette72
    In the specific case of n=1.4 we are definately dealing with an isentropic process.

    Returning to the original question which was the derivation of another formula from PV^n=C.

    "
    From Pv^n =C ....

    (P^(1/n))(T/P) = C

    or

    TP^((1-n)/n) = C
    "

    I do not think the value of n will affect the derivation of the formula.
    for an isentropic gas expansion (or compression). See the links in my post above. The fact that for a diatomic gas is not relevant.
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