Gas Specific Gravity and Ideal Gas Law Calculator Gas Specific Gravity Universal Gas Constant Pressure, Temperature, Density, Mass, Volume using Ideal Gas Law. Register to enable "Calculate" button for Ideal Gas Law calculator.

Gas Specific Gravity and Molecular Weight Conversion (free):

S = M / Mair , where S=gas specific gravity, M=gas molecular weight, Mair=28.96443 g/mole (molecular weight of standard air - CRC, 1983).

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Ideal Gas Equation (CRC, 1983). (Calculation requires registration):

Ru = 8.3144126  N-m/mole-K

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The ideal gas law calculation internally converts all user inputs to SI units, performs the calculation, then converts calculated values to user-desired units.  All molecular weights are from CRC (1983).  The molecular weight of air is computed from the volume fractions of the individual components in air given by CRC (1983):

Fractional Volumes of Components in Sea Level Dry Air (CRC, 1983)

 Component: N2 O2 Ar CO2 Ne He Kr Xe CH4 H2 Volume Fraction 0.78084 0.209476 9.34e-3 3.14e-4 1.818e-5 5.24e-6 1.14e-6 8.7e-8 2e-6 5e-7

Error Messages given by Ideal Gas calculation
"Inputs must be positive".  This is an initial check of user input.   The only negative values that may be input are temperature expressed in oC or oF.
"T must be > -273.15 oF".  This message will appear if temperature is entered in oC.  -273.15 oC corresponds to absolute zero.
"T must be > -459.67 oR".  This message will appear if temperature is entered in oF.  -459.67 oF corresponds to absolute zero.

References
Chemical Rubber Company (CRC).  1983.  CRC Handbook of Chemistry and Physics. Weast, Robert C., editor.  63rd edition.  CRC Press, Inc.  Boca Raton, Florida.  USA.