vapour

physics
Also known as: vapor

Learn about this topic in these articles:

absolute humidity

  • In absolute humidity

    vapour concentration or density in the air. If mv is the mass of vapour in a volume of air, then absolute humidity, or dv, is simply dv = mv/ V, in which V is the volume and dv is expressed

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chemical distillation

  • In separation and purification: Distillation

    …a definite amount of its vapour is present. The concentration of the vapour and, therefore, the pressure that it exerts increase as the temperature is raised. When the pressure of the vapour equals the pressure of the surroundings (one atmosphere in an open vessel at sea level), the substance boils:…

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crystal growth

  • Figure 1: Unit cells for face-centred and body-centred cubic lattices.
    In crystal: Vapour growth

    Crystals can be grown from a vapour when the molecules of the gas attach themselves to a surface and move into the crystal arrangement. Several important conditions must be met for this to occur. At constant temperature and equilibrium conditions, the average number…

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gas chromatographic detection

  • elution chromatography
    In chromatography: Gas chromatographic detectors

    …chromatographic detectors sense the solute vapours in the mobile phase as they emerge from the column. Thermal-conductivity detectors compare the heat-conducting ability of the exit gas stream to that of a reference stream of pure carrier gas. To accomplish this, the gas streams are passed over heated filaments in thermal-conductivity…

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saturation

  • In saturation

    …and the state of a vapour similarly left in contact with the pure solid or liquid form of the substance. In the first example, the solution is saturated when the rate at which the pure substance dissolves in the solvent to enter the solution is exactly equal to the rate…

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