Question

A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure. What mass of carbon dioxide can it hold under similar conditions of temperature and pressure?

Answer 1

Let the volume of the cylinder = V

Vapour density of hydrogen (2) = `"Molecular mass"/2`

= `2/2`

= 1

Vapour density of carbon dioxide (CO₂) = `"Molecular mass"/2`

= `44/2`

= 22

Mass of hydrogen in the cylinder (or volume v) = 1 kg

Let the mass of the carbon dioxide in the cylinder (of volume v) at the same temperature and pressure = m kg

Now, 

Vapour density of CO₂ = `"Mass of certain volume (v) of CO"_2/"Mass of same volume (v) of hydrogen at the same temperature and pressure"` 

∴ 22 = `"m"/1`

or, m = 22 kg