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The gas constant

  1. Dec 5, 2011 #1
    Hi there,

    I've had an assignment recently about turbine blades which involved lots of calculations with the gas constant (R). Working away at my report I came across the ideal gas law that use the gas constant in its equation, and I was wondering if temperature or air pressure effect the Gas constant at all? For example would the gas constant change if pressure was 25kPa as opposed to 100kPa?

    Thanks in advance!
     
  2. jcsd
  3. Dec 5, 2011 #2
    From my understanding the universal gas constant itself is a constant.

    The departure of the ideal gas law is expressed as correction terms to the pressure and volume due to intermolecular forces and the fact that molecules do occupy some space rather than being point particles. R is not a function of temperature.

    See here:
    http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/waal.html#c1
     
  4. Dec 5, 2011 #3

    AlephZero

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    R is a constant, by definition.

    What is not "constant" is the equation of state, which links the gas pressure, volume, and temperature. The "ideal gas law" PV = nRT is the simplest equation of state and accurate enough for many purposes, but there have been many improvements to it.
    http://en.wikipedia.org/wiki/Equation_of_state
     
  5. Dec 5, 2011 #4
    So the gas constant itself will always remain at 287 Jkg/K despite atmospheric pressure/temperature? As these variables are not used in the calculation of R?
     
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