Vapour Density

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

Other articles related to "vapour density, vapour":

Vapour Density - Alternative Definition
... vapour density is defined with respect to air, not hydrogen ... Air is given a vapour density of one ... a molecular weight of 28.97 atomic mass units, and all other gas and vapour molecular weights are divided by this number to derive their vapour density ...
Molar Mass - Measurement - Vapour Density
... The measurement of molar mass by vapour density relies on the principle, first enunciated by Amadeo Avogadro, that equal volumes of gases under identical conditions contain equal numbers of particles ... The vapour density (ρ) is given by Combining these two equations gives an expression for the molar mass in terms of the vapour density for conditions of known pressure and temperature ...

Famous quotes containing the word vapour:

    Thy great leaves enfold
    The ancient beards, the helms of ruby and gold
    Of the crowned Magi; and the king whose eyes
    Saw the Pierced Hands and Rood of elder rise
    In Druid vapour and make the torches dim....
    William Butler Yeats (1865–1939)