All gases may be considered, to a first approximation, to obey the ideal gas equation which relates the pressure p, volume V, temperature T  and amount of substance n of a gas. The amount of gas n is expressed as the number of moles and is equal to m / M  where m is the mass of gas present and M  is the mass of one mole of the gas. The volume occupied by a known mass of gas is to be measured at a given temperature and pressure, so that the ideal gas equation can be used to estimate the molar mass of the gas.


  • Examination of many different gases possible
  • Illustrative experimental setup


Determine the molar masses of the gases helium, nitrogen, carbon dioxide and methane.

What you can learn about

  • Molar mass and relative molar mass
  • Properties of gases
  • Ideal and ordinary gases
  • Equations of state

Necessary accessories

  • Precision balance 620g/0.001g

Scope of Supply
Device NameItem no.Qty
Rotary valve vacuum pump, two stages, 115 V / 230 V02741-951,00
Glass tubes, right-angled, 1036701-571,00
Glass sphere, 2 stopcocks, 100 ml36810-001,00
Silicon grease Molykote, 50 g31863-051,00
Weather monitor, 6 lines LCD87997-101,00
Rubber tubing,vacuum,i.d.8mm39288-001,00
Glass tube, right-angled36701-071,00
Gas-syringe holder with stop02058-001,00
Compressed gas, nitrogen, 12 l41772-041,00
Right angle boss-head clamp37697-007,00
Fine control valve33499-001,00
Tripod base PHYWE02002-552,00
Hose clip f.12-20 diameter tube40995-002,00
Gas syringe, 100 ml, with 3-way cock02617-001,00
Compressed gas, CO2, 22 g41772-061,00
Universal clamp37715-004,00
Secure bottle, 500 ml, 2 x Gl 18/8, 1 x 25/1234170-011,00
Support rod, stainless steel, l = 250 mm, d = 10 mm02031-002,00
Hose clip, diam. 8-16 mm, 1 pc.40996-024,00
Stopcock,3-way,t-shaped, glass36731-001,00
Adapter for vacuum pump02657-001,00
Compressed gas, methane, 12 l41772-081,00
Rubber tubing,vacuum,i.d.6mm39286-003,00
Spring manometer, 0...-1000 mbar34170-021,00
Support rod, stainless steel, 750 mm02033-001,00
Compressed gas, helium, 12 l41772-031,00
Downloads and Documents

Document  Filesize
p3010401e.pdfExperiment guide, English288.99 KB