Ideal Gas Law Calculator

PV = nRT

Calculation Result

Solution Steps:

Example Problems

Example 1: Solving for Volume

A gas has a pressure of 2 atm, temperature of 300 K, and contains 0.5 moles. What is its volume?

Click to load this example
Example 2: Solving for Pressure

A gas with 1 mole is contained in a 22.4 L container at 273 K. What is the pressure?

Click to load this example
Example 3: Solving for Temperature

A 0.25 mole gas sample occupies 5.0 L at 1.5 atm pressure. What is the temperature?

Click to load this example
Example 4: Solving for Moles

A 10.0 L tank contains gas at 3.0 atm pressure and 350 K. How many moles of gas are present?

Click to load this example

Interactive Guide

The Ideal Gas Law is a fundamental equation in chemistry and physics that describes the relationship between pressure (P), volume (V), temperature (T), and the number of moles (n) of an ideal gas. The equation is:

PV = nRT

Where:

  • P = Pressure (in atm, Pa, mmHg, etc.)
  • V = Volume (in L, m³, etc.)
  • n = Number of moles of gas
  • R = Ideal gas constant (value depends on units)
  • T = Temperature (in Kelvin)

  1. Enter known values for three of the four variables (P, V, n, T)
  2. Check the checkbox for the variable you want to solve for
  3. Select appropriate units for each variable
  4. Choose the gas constant (R) that matches your unit system
  5. Click "Calculate" to get the result
Tip: Make sure all units are consistent. The calculator will automatically handle some conversions, but it's best to use matching units (e.g., atm with L, or Pa with m³).

Value Units When to Use
0.0821 L·atm/(mol·K) When pressure is in atm and volume in liters
8.314 J/(mol·K) When using SI units (Pa for pressure, m³ for volume)
62.364 L·mmHg/(mol·K) When pressure is in mmHg and volume in liters

About Gas Laws

The Ideal Gas Law

The Ideal Gas Law combines several simpler gas laws (Boyle's Law, Charles's Law, Avogadro's Law) into one comprehensive equation. It describes the behavior of an "ideal gas" - a hypothetical gas whose molecules occupy negligible space and have no intermolecular interactions.

While real gases deviate from ideal behavior at high pressures and low temperatures, the Ideal Gas Law provides a good approximation for many gases under normal conditions.

Limitations
  • Doesn't account for molecular volume or intermolecular forces
  • Less accurate at high pressures or low temperatures
  • Not applicable to phase changes (condensation, etc.)

For more accurate calculations with real gases, the Van der Waals equation or other equations of state may be used.

Applications
  • Predicting gas behavior in chemical reactions
  • Designing pressure vessels and containers
  • Calculating gas densities
  • Understanding atmospheric phenomena
  • Industrial processes involving gases