# Ideal Gas Law Calculator

This ideal gas law calculator will help you establish the properties of an ideal gas subject to changes of pressure, temperature or volume. Read on to learn what are the characteristics of an ideal gas, how to use the ideal gas law equation and what is the definition of an ideal gas constant.

## What is an ideal gas

An ideal gas is a special case of any gas that fulfills the following conditions:

- The gas consists of a large amount of molecules that move around randomly.
- All molecules are point particles (they don't take up any space).
- The molecules don't interact except for colliding.
- All collisions between the particles of the gas are perfectly elastic.
- The particles obey Newton's laws of motion.

## Ideal gas law equation

The properties of an ideal gas are all lined in one formula of the form `pV = nRT`

, where:

`p`

is the pressure of the gas, measured in Pa,`V`

is the volume of the gas, measured in m^3,`n`

is the amount of substance, measured in moles,`R`

is the ideal gas constant and`T`

is the temperature of the gas, measured in Kelvins.

To find any of these values, simply enter the other ones in the ideal gas law calculator.

For example, if you want to calculate the volume of 40 moles of a gas under the pressure of 1013 hPa and in the temperature 250 K, the result will be equal to:

`V = nRT/p = 40 * 8.3144598 * 250 / 101300 = 0.82 m^3`

.

## Ideal gas constant

The gas constant (symbol R) is also called the molar or universal constant. It is used in many fundamental equations such as the ideal gas law.

The value of this constant is 8.3144598 J/(mol * K).

The gas constant is often defined as the product of Boltzmann's constant `k`

(it relates the kinetic energy and temperature of a gas) and Avogadro number (number of atoms in a mole of substance):

`R = k/N = 1.38064852)*10^(-23) J/K /(6.022140857 * 10^23 1/mol) = 8.3144598 J/(mol * K)`

You might find this air pressure at altitude calculator useful, too.