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Ideal gas law Calculator

Relate pressure, volume and temperature for a gas.

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Pressure

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Overview

The ideal gas law represents the equation of state for a hypothetical ideal gas, combining Boyle's, Charles's, and Avogadro's laws into one relationship. It establishes a mathematical connection between the pressure, volume, absolute temperature, and the molar amount of gas present in a system.

Symbols

Variables

p = Pressure, V = Volume, n = Amount of Gas, T = Temperature, R = Gas Constant

Pressure
Pa
Volume
Amount of Gas
mol
Temperature
Gas Constant
J/molK

Apply it well

When To Use

When to use: Use this equation when analyzing the behavior of gases at relatively low pressures and high temperatures where molecules act independently. It is the primary tool for determining a missing physical property of a gas sample when the other state variables are defined.

Why it matters: This relationship is essential for chemical engineering, meteorology, and the design of pneumatic systems. It allows for the calculation of gas density and molar mass, which are critical for industrial safety and atmospheric research.

Avoid these traps

Common Mistakes

  • Using Celsius.
  • Using dm³ without checking R units.
  • Forgetting that temperature must be in Kelvin (add 273).
  • Using the wrong value of R for the units being used.

One free problem

Practice Problem

A 2.50 mole sample of oxygen gas is placed in a 5.00 L container at a temperature of 300 K. Calculate the pressure in atmospheres using R = 0.0821 L·atm/mol·K.

Amount of Gas2.5 mol
Volume5 m^3
Temperature300 K
Gas Constant0.0821 J/molK

Solve for:

Hint: Rearrange the formula to p = nRT / V.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. Atkins' Physical Chemistry
  2. Halliday, Resnick, and Walker, Fundamentals of Physics
  3. Wikipedia: Ideal gas law
  4. IUPAC Gold Book: Ideal gas
  5. NIST CODATA 2018
  6. Atkins' Physical Chemistry, 11th ed.
  7. IUPAC Gold Book
  8. Atkins' Physical Chemistry (e.g., Peter Atkins, Julio de Paula, James Keeler)