ChemistryIntermediate10 min read • October 4, 2025

The Ideal Gas Law: PV = nRT

A powerful approximation that explains a lot of everyday phenomena.

The Formula

P × V = n × R × T

P: pressure • V: volume • n: moles • R: gas constant • T: temperature

Quick Example

At 1 atm and 300 K with 0.5 moles, what volume? V = nRT/P ≈ (0.5 × 0.08206 × 300) / 1 ≈ 12.3 L

When It Breaks

  • High pressures or very low temperatures
  • Strong intermolecular forces (real gases)
  • Near condensation points

Try This

Leave a balloon in the sun and watch it expand—temperature up, volume up.

Next: Normal Distribution →