Free · Thermodynamics and heat calculators 🌡️

Specific Gas Constant from Molar Mass or Heat Capacities

Calculate specific gas constant from molar mass or heat capacities using known measurements, selectable units and clear physical assumptions.

Formula & worked example
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How to use this calculator

Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

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Formula and method

For molar mass 0.02897 kg/mol, Rₛ = 8.31446261815324/0.02897 J/(kg·K).

Rₛ = Rᵤ/M = cₚ − cᵥ

Worked example

Enter these known values and leave the other values blank.

Molar mass per mole: .02897 kg /mol

Specific gas constant: 287 J/(kg·K)

Assumptions and limitations

Molar-mass selectors represent mass per mole: the initial kg selector means kg/mol. The heat-capacity difference applies to an ideal gas with both heat capacities measured for the same mass basis and thermodynamic state.
Enter mutually consistent measurements and clear a quantity before inferring it. Calculations use 64 significant digits; the displayed result is rounded separately.

Common questions

How do the two methods differ?

Choose molar mass to use Rᵤ/M, or specific heat to use cₚ−cᵥ. The second method requires consistent ideal-gas heat capacities in J/(kg·K) or a compatible mass-based unit.

References

Calorie-based specific heats use the thermochemical calorie, exactly 4.184 joules, consistently with the heat-capacity units.

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