How to Find the Density of a Gas

Density is calculated by dividing the mass of a substance by its volume. Although the density of solids and liquids usually uses the unit g/mL, the density of gases uses the unit g/L. This is because gases contain a lot of empty space, so they are much less dense than solids and liquids. To calculate the density of a gas, it is easiest to calculate the density of a given amount of gas--specifically, a mole.

Things You'll Need

• Periodic table
• Calculator

Instructions

1. On the periodic table, locate the gas whose density you are calculating.

2. Find the gas's atomic weight, which is usually listed in the top corner of the box containing the gas. The unit of the atomic weight is g/mol.

3. Divide the atomic weight by 22.4 L/mol, which is the molar volume of a gas. The result, which is the density of the gas, will be in g/L.

Tips & Warnings

• Density is not dependent on mass. Therefore, larger amounts of a gas will have the same density as smaller amounts of the same gas.

References

• Chemistry SparkNotes - Density of Gases

Resources

• Interactive Periodic Table