Two figures in, a clear answer out. The van der waals equation calculator uses temperature, volume, molar volume, amount of substance and pressure to produce temperature, constant a and constant b, applying the standard relationship for this problem in the order the calculation actually needs it.
What Is the Van Der Waals Equation Calculator?
This van der waals equation calculator is for the kind of problem where you know the physical quantities but not the number you need. It turns temperature, volume, molar volume, amount of substance and pressure into temperature, constant a and constant b.
Physics calculations go wrong in predictable ways, usually through mixing units or dropping a digit. Work through the result one step at a time and check that the figures are the size you would expect at each stage.
How the Van Der Waals Equation Physics Works
The relationship is applied step by step, and each step is a standard piece of physics rather than a single opaque formula. That means you can check the intermediate values against what the theory predicts, which is usually faster than checking only the final answer.
Keep every value in the same unit system throughout the calculation. Mixing metres and feet part way through is the single most common reason a correct formula gives a wrong answer.
Units, Assumptions and the Limits of the Model
The calculation assumes ideal conditions: no air resistance, no heat loss, and dimensions that do not change while you work. Those assumptions are reasonable for most classroom and engineering estimates, and unreasonable for anything more precise.
Where a value is a rate, it has to be quoted for the same period as everything else. A per-hour figure cannot be combined with a per-day figure without converting one of them first.
A Worked Example
Working through an example, with temperature set to 10, volume set to 5, molar volume set to 2, the calculator returns pressure of 15.58961, and constant a of 187.07535, and constant b of 0.66667. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out temperature?
Enter temperature, volume, molar volume, amount of substance and pressure. The calculator then works through the relationship and reports temperature, constant a and constant b.
What does the van der waals equation actually calculate?
It takes temperature, volume, molar volume, amount of substance and pressure and converts them into temperature, constant a and constant b using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter temperature?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Is the answer exact?
It is as exact as the formula and the inputs allow. The method itself is the standard one for this problem, so the only sources of error are the figures you enter and the precision you ask for.
Do I have to fill in every field?
Only the fields a particular result depends on. If you leave one blank, the results that need it simply show a note instead of a number, and everything else still works.