All calculatorsMolar Volume Calculator
Compute the volume occupied by 1 mole of gas under specified conditions. At STP (1 atm, 273.15 K), this value is ~22.4 L·mol⁻¹. You can also calculate molar volume at custom pressure and temperature using the ideal gas law.
Background
The molar volume of a substance is the volume occupied by one mole. For ideal gases, use Vm = RT / P. At STP (1 atm, 273.15 K), this gives 22.414 L·mol⁻¹. For other conditions, adjust T (K) and P (atm or Pa) accordingly.
How to use this calculator
- STP: Returns 22.414 L·mol⁻¹ directly.
- Custom: Enter T and P, choose units. We use Vm = RT/P (with R = 0.082057 L·atm·mol⁻¹·K⁻¹ or 8.314 J·mol⁻¹·K⁻¹ for Pa).
Example Problems & Step-by-Step Solutions
Example 1 (STP)
At STP (1 atm, 273.15 K): Vm = 22.414 L·mol⁻¹.
Example 2 (Custom)
At 298 K and 1 atm: Vm = (0.082057×298)/1 ≈ 24.5 L·mol⁻¹.
Frequently Asked Questions
Q: What is molar volume?
The volume occupied by one mole of a substance. For ideal gases, Vm = RT/P.
Q: What is the molar volume at STP?
At STP (1 atm, 273.15 K) the ideal-gas molar volume is 22.414 L·mol⁻¹.
Q: Why can measured values deviate from 22.4 L·mol⁻¹?
Real gases exhibit intermolecular forces and finite molecular size; deviations grow at high pressure and low temperature.
Q: Can I use this for liquids/solids?
This tool is intended for gases. Liquids/solids have much smaller molar volumes and require density or EOS data.
