Specific Gas Constant
Rspecific for dry air |
Units |
---|---|
287.04 | J kg−1 K−1 |
53.3533 | ft lbf lb−1 °R−1 |
1716.49 | ft lbf slug−1 °R−1 |
The specific gas constant of a gas or a mixture of gases (Rspecific) is given by the molar gas constant, divided by the molar mass (M) of the gas/mixture.
Just as the ideal gas constant can be related to the Boltzmann constant, so can the specific gas constant by dividing the Boltzmann constant by the molecular mass of the gas.
Another important relationship comes from thermodynamics. This relates the specific gas constant to the specific heats for a calorically perfect gas and a thermally perfect gas.
where cp is the specific heat for a constant pressure and cv is the specific heat for a constant volume.
It is common, especially in engineering applications, to represent the specific gas constant by the symbol R. In such cases, the universal gas constant is usually given a different symbol such as R to distinguish it. In any case, the context and/or units of the gas constant should make it clear as to whether the universal or specific gas constant is being referred to.
Read more about this topic: Gas Constant
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