Wolfram|Alpha has gases calculators. Solve problems related to Avogadro's, Boyle's, Charles's or Gay‐Lussac's law; the combined gas law; the compressibility factor for a van der Waals gas; Graham's law of diffusion; the heat capacity or internal energy of an ideal gas; the ideal gas law; the Maxwell speed distribution probability; mean free paths; the Peng–Robinson, Redlich–Kwong or van der Waals equation of state; the Sackur–Tetrode equation; and gas particles' velocity.
