Van der Waals Equation Calculator

Your details

Choose a preset gas to auto-fill van der Waals constants, or pick Custom to enter your own.
Select which variable you want the calculator to find.
Container volume in litres.
L
Temperature in Kelvin.
K
Number of moles of gas.
mol
Result
11.6768

The solved variable from the van der Waals equation.

Unitatm
Ideal gas prediction12.3086
Deviation from ideal-0.05%
Pressure correction (an^2/V^2)0.9013
Volume correction (nb)0.0429
Constant a3.605
Constant b0.04286
Attraction correction (atm)0.9013
Excluded volume (L)0.0429
Constant a3.605
Constant b0.04286

Carbon Dioxide (CO2): pressure = 11.6768 atm

  • Real pressure is 5.13% lower than ideal: intermolecular attraction dominates, pulling molecules together and reducing pressure.
  • The attraction correction (an^2/V^2) is 0.9012 atm, reducing effective pressure.
  • The excluded-volume correction (nb) is 0.0429 L, reducing free space for motion.
  • Carbon Dioxide (CO2) has a relatively high attraction constant (a = 3.605), meaning strong intermolecular forces. The ideal gas law significantly underestimates this.

Next stepFor a complete picture of non-ideal behavior, also calculate the compressibility factor Z = PV/(nRT). Z = 1 for a perfect ideal gas; deviations signal real-gas effects.

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