# How do you calculate the molar volume of a gas at STP?

May 25, 2014

The Molar Volume of a gas at STP is a constant using Avogadro's value of 22.4 L/mol.

To calculate this we can use the Ideal gas law of $P V = n R T$

At STP (Standard Temperature and Pressure)
P = 1 atm
V = ?
n = 1 mol
R = 0.0821 $\frac{a t m L}{m o l K}$
T = 273 K

$\left(1 a t m\right) \left(V\right) = \left(1 m o l\right) \left(0.0821 \frac{a t m L}{m o l K}\right) \left(273 K\right)$

$V = \frac{\left(1 m o l\right) \left(0.0821 \frac{a t m L}{m o l K}\right) \left(273 K\right)}{1 a t m}$

$V = 22.4 \frac{L}{m} o l$