How to Calculate Ideal Gas Law
What is Ideal Gas Law?
The ideal gas law PV = nRT relates pressure (P), volume (V), moles (n), and temperature (T) of an ideal gas. R = 8.314 J/(mol·K) is the universal gas constant.
Step-by-Step Guide
- 1Identify which variable you need to find
- 2Temperature must be in Kelvin: K = °C + 273.15
- 3Rearrange PV = nRT for the unknown
- 4An "ideal gas" has no intermolecular forces — real gases deviate at high pressure/low temperature
Worked Examples
Input
1 mol at 0°C, 1 atm (101,325 Pa)
Result
V = 22.4 L
Standard molar volume at STP
Input
P₁=1 atm, V₁=10L, T₁→T₂ (double)
Result
V₂=20 L
Pressure constant, Charles's Law
Ready to calculate? Try the free Ideal Gas Law Calculator
Try it yourself →