Molar Mass of Gas Calculator

Your details

Mass of the gas sample in grams.
g
Absolute pressure of the gas. Select the unit that matches your measurement.
Volume occupied by the gas sample.
Temperature of the gas. The calculator converts to Kelvin automatically.
Correction for real-gas behaviour. Z = 1 for an ideal gas (the default). Values below 1 indicate attractive intermolecular forces; values above 1 indicate repulsive forces. Consult a van der Waals table for your specific gas.
Molar massHydrogen-range gas
2.016g/mol

Mass per mole of the gas (M = mRT / ZPV)

Moles of gas1mol
Temperature (K)273.15K
Pressure (atm)1atm
Volume (L)22.414L
Moles (mol)1
Molar mass (g/mol)2.016

Molar mass: 2.016 g/mol

  • A molar mass of 2.02 g/mol is close to H2 (hydrogen).
  • The sample contains 1.0000 mol, equivalent to 6.022e+23 molecules (by Avogadro's number).
  • Z = 1 assumes ideal-gas behaviour. For high pressures or temperatures near the gas's critical point, use a compressibility chart (Nelson-Obert or NIST) to find Z.

Next stepCompare the result to known molar masses in a periodic table or CRC Handbook to identify or verify the gas. If the value seems off, check that your pressure is absolute (not gauge) and your temperature is correct.

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