Compare the volume of 14.1 g of helium to 14.1 g of argon gas (under identical conditions).

The Volumes can be calculated from Masses by using following Formula,

Density = Mass / Volume

Solving for Volume,

Volume = Mass / Density

Mass of Both Gases = 14.1 g

Density of Argon at S. T. P = 1.784 g/L

Density of Helium at S. T. P = 0.179 g/L

For Argon:

Volume = 14.1 g / 1.784 g/L

Volume = 7.90 L

For Helium:

Volume = 14.1 g / 0.179 g/L

Volume = 78.77 L