Created By : Vaibhavi Kumari

Reviewed By : Rajashekhar Valipishetty

Last Updated : May 17, 2023

This Van Der Waals Equation calculator is a useful tool for analysing real-world gas physical properties. It employs the van der Waals equation, a thermodynamic state equation that improves on the ideal gas law equation. Have you ever wondered what the definition of a true gas is? If you want to discover more about the actual gas definition and law, keep reading.

Choose a Calculation
Pressure (Pc)
Molar volume (Vc)

Van Der Waals Equation Definition

Van der Waals introduced two parameters (the so-called van der Waals parameters) that are connected to the critical point of a gas, i.e. the point at which liquid and vapour cannot be distinguished (liquid and its vapour can coexist). We've also talked about the significance of these constants and how to estimate them in the text below.

Ideal Gas vs Real Gas

An ideal gas is made up of a huge number of randomly moving point particles that can collide with one another and the container's walls. It's a kinetic molecular theory, which we've discussed in detail in our thermal energy calculator. You might also be interested in our particle velocity calculator, which calculates the average particle velocity in a gas at a particular temperature.

The real gas law, which is a variation of the ideal gas law, considers two extra factors

  • Molecules can not only collide with one other as they would in an ideal gas, but they can also attract each other within a few molecule radii. Because the container's surface is devoid of gas particles, molecules at the surface are drawn into the substance. As a result, the real gas pressure on the container walls is lower than in an ideal gas.
  • Molecules are non-zero volume particles, not material points like in an ideal gas. As a result, the volume of a full gas cannot be smaller than a fixed value.

Van Der Waals State Equation

There are two elements to our van der Waals equation calculator. To estimate van der Waals constants, you must first provide the crucial parameters of the considered gas. In advanced mode, you can alter those constants directly or select one of the common gases.

With the following relationship, you may learn what is the relationship between volume, pressure, and temperature in real gas in the second section of the van der Waals equation calculator i.e. (p + a x (n / V)²) x (V / n - b) = R x T

  • where p = pressure of a gas,
  • V = volume of a gas,
  • T = temperature of a gas,
  • n = number of moles of gas,
  • R = gas constant R = 8.3144598 J / (mol * K),
  • a and b are van der Waals parameters

The volume of one mole of molecules corresponds to the constant b value (it is a correction for finite molecular size). As a result, we must apply the constraint V / n > b to avoid a situation in which the volume of the molecules exceeds that of the entire gas. The Van Der Waals Equation is an excellent approximation of the genuine gas state equation in most cases, especially at high pressures and around the gas condensation parameters in temperature and pressure.

How to use the Van Der Waals Equation Calculator?

The following is the procedure how to use the Van der Waals equation calculator

  • Step 1: In the input field, enter the volume, temperature, number of moles, and particle attraction measure.
  • Step 2: To calculate the pressure of the ideal gas, click the calculate Pressure option.
  • Step 3: Finally, the pressure of the ideal gas will be displayed in the output field using the Van der Waals equation.

FAQs on Van Der Waals Equation

1. What is the formula for calculating Van Der Waals?

The van der Waals equation is a state equation that accounts for two aspects of real gases: gas-particle excluded volume and gas molecule attractive forces. (P+an2V2)(V−nb)=nRT ( P + a n 2 V 2 ) ( V − n b ) = n R T

2. How are the Van Der Waals Constants A and B calculated?

(P+V2a​​)(V−b)=RT is the van der Waal's gas equation, where P is the pressure, V is the molar volume, and T is the temperature of the provided gas sample. The molar gas constant is R, while the van der Waal constants are a and b. For a dimensional formula is the same as for.

3. What Does the Van Der Waals Equation Mean?

The Van Der Waals equation establishes a link between the volume, pressure, and absolute temperature of a real gas. It also takes into account two other factors: intermolecular attraction and the molecule's finite size.

4. What do the constants A and B in the Van Der Waal Equation mean?

The magnitude of intermolecular attractive forces between the particles is measured by the constant "a." The constant "b" measurement of a gas molecule's volume.