Ideal Gas Law
Links pressure, volume, amount and temperature of a gas.
PV = nRT
1What it means
Describes how an ideal gas behaves: at fixed temperature, squeezing the volume raises the pressure. R is the universal gas constant.
2Variables
| Symbol | Meaning |
|---|---|
| P | Pressure (atm) |
| V | Volume (litres, L) |
| n | Amount of gas (moles) |
| R | Gas constant ≈ 0.0821 L·atm·K⁻¹·mol⁻¹ |
| T | Temperature (kelvin, K) |
3Worked examples
Example 1 Worked solution
Q. Find the volume of 2 mol of gas at 1 atm and 273 K.
- PV = nRT ⇒ V = nRT / P.
- = (2 × 0.0821 × 273) / 1.
✓ V ≈ 44.8 L
4Where it's used
- ✦Gas calculations in labs and industry.
- ✦Relating gas volume to temperature and pressure changes.
5Tips & common mistakes
- !Temperature must be in kelvin: K = °C + 273.
- !Match R to your units (use 0.0821 for atm and litres).