Vapour density is the density of a vapour in relation to that of hydrogen. It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen.
vapour density = mass of n molecules of gas / mass of n molecules of hydrogen
Therefore:
vapour density = molar mass of gas / molar mass of H2
vapour density = molar mass of gas / 2.0016
vapour density = ~½ × molar mass
(and thus: molar mass = ~2 × vapour density)
Read more about Vapour Density: Alternative Definition
Famous quotes containing the word vapour:
“O curse of marriage,
That we can call these delicate creatures ours
And not their appetites! I had rather be a toad,
And live upon the vapour of a dungeon
Than keep a corner in the thing I love
For others’ uses.”
—William Shakespeare (1564–1616)