How to use the van der waals real gas calculator
Estimate real gas pressure using the van der Waals equation. Enter gas, amount, volume, temperature in the fields above; the real gas pressure, ideal gas pressure, difference are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- g — Gas
- n — Amount (mol)
- V — Volume (L)
- T — Temperature (K)
Worked example
With gas = CO₂, amount = 1 mol, volume = 1 L, temperature = 300 K, the calculator gives real gas pressure ≈ 22.41598 bar; ideal gas pressure ≈ 24.94339 bar; difference ≈ -10.13259 %.
Frequently asked questions
What is the formula for the van der waals real gas calculation?
Real gas pressure (bar) = n × 0.08314462 × T / (V-n × [0.0427,0.0387,0.0319,0.0266,0.0371,0.0542][g])-[3.64,1.37,1.38,0.245,4.225,6.34][g] × n × n / (V × V). Ideal gas pressure (bar) = n × 0.08314462 × T / V. Difference (%) = 100 × ([Real gas pressure]-[Ideal gas pressure]) / [Ideal gas pressure]. Here g is gas, n is amount (mol), V is volume (L), T is temperature (K).
What inputs do I need for the van der waals real gas calculator?
You need gas, amount in mol, volume in L, temperature in K. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.