# Calculate pressure of a real gas using Van der Waal’s Equation

• Difficulty Level : Easy
• Last Updated : 21 Apr, 2021

Given integers V, T, and n representing the volume, temperature and the number of moles of a real gas, the task is to calculate the pressure P of the gas using Van der Waal’s Equation for real gas.

Van der Waal’s Equation for Real Gas:
( P + a * n2 / V2 ) * (V – n * b) = n R T)
where, average attraction between particles (a) = 1.360,
volume excluded by a mole of particles (b) = 0.03186,
Universal Gas constant (R) = 8.314

Examples:

Input: V = 5, T = 275, n = 6
Output: 2847.64

Input: V = 7, T = 300, n = 10
Output: 3725.43

Approach: To solve the problem, simply calculate the pressure P of real gas by using the equation P = ((n * R * T) / (V â€” n * b)) â€” (a* n * n) / (V * V) and print the result.

Below is the implementation of the above approach:

## C++

 `// C++ Program to implement``// the above approach` `#include ``using` `namespace` `std;` `// Function to calculate the pressure of a``// real gas using Van der Wall's equation``void` `pressure_using_vanderwall(``double` `V,``                               ``double` `T, ``double` `n)``{` `    ``double` `a = 1.382;``    ``double` `b = 0.031;``    ``double` `R = 8.314;` `    ``// Calculating pressure``    ``double` `P = ((n * R * T) / (V - n * b))``               ``- (a * n * n) / (V * V);` `    ``// Print the obtained result``    ``cout << P << endl;``}` `// Driver code``int` `main()``{` `    ``double` `V = 7, T = 300, n = 10;``    ``pressure_using_vanderwall(V, T, n);``    ``return` `0;``}`

## Java

 `// Java program to implement``// the above approach``class` `GFG{``    ` `// Function to calculate the pressure of a``// real gas using Van der Wall's equation``public` `static` `void` `pressure_using_vanderwall(``double` `V,``                                             ``double` `T,``                                             ``double` `n)``{``    ``double` `a = ``1.382``;``    ``double` `b = ``0.031``;``    ``double` `R = ``8.314``;`` ` `    ``// Calculating pressure``    ``double` `P = ((n * R * T) / (V - n * b)) -``                ``(a * n * n) / (V * V);`` ` `    ``// Print the obtained result``    ``System.out.println(String.format(``"%.2f"``, P));``}` `// Driver Code``public` `static` `void` `main(String[] args)``{``    ``double` `V = ``7``, T = ``300``, n = ``10``;``    ` `    ``pressure_using_vanderwall(V, T, n);``}``}` `// This code is contributed by divyesh072019`

## Python3

 `# Python3 Program to implement``# the above approach` `# Function to calculate the pressure of a``# real gas using Van der Wall's equation``def` `pressure_using_vanderwall(V, T, n):` `    ``a ``=` `1.382``    ``b ``=` `0.031``    ``R ``=` `8.314` `    ``# Calculating pressure``    ``P ``=` `((n ``*` `R ``*` `T) ``/` `(V ``-` `n ``*` `b)) ``-` `(a ``*` `n ``*` `n) ``/` `(V ``*` `V)` `    ``# Print the obtained result``    ``print``(``round``(P, ``2``))` `# Driver code``V, T, n ``=` `7``, ``300``, ``10``pressure_using_vanderwall(V, T, n)` `# This code is contributed by divyeshrabadiya07`

## C#

 `// C# program to implement``// the above approach``using` `System;` `class` `GFG{``     ` `    ``// Function to calculate the pressure of a``    ``// real gas using Van der Wall's equation``    ``public` `static` `void` `pressure_using_vanderwall(``double` `V,``                                                 ``double` `T,``                                                 ``double` `n)``    ``{``        ``double` `a = 1.382;``        ``double` `b = 0.031;``        ``double` `R = 8.314;``      ` `        ``// Calculating pressure``        ``double` `P = ((n * R * T) / (V - n * b)) -``                    ``(a * n * n) / (V * V);``      ` `        ``// Print the obtained result``        ``Console.WriteLine(Math.Round(P, 2));``    ``}``     ` `    ``// Driver Code``    ``public` `static` `void` `Main(String[] args)``    ``{``        ``double` `V = 7, T = 300, n = 10;``         ` `        ``pressure_using_vanderwall(V, T, n);``    ``}``}`` ` `// This code is contributed by AnkitRai01`

## Javascript

 ``
Output:
`3725.43`

Time Complexity: O(1)
Auxiliary Space: O(1)

My Personal Notes arrow_drop_up