Vapours

Contents / notes

• Unsaturated and saturated vapours.
• Relationship between saturated vapour pressure (SVP) and boiling.
• Determination of SVP by the barometer tube method.
• Formation of dew, mist, fog, cloud and rain.
• Dew point, humidity and relative humidity.
• Hygrometry and estimation of atmospheric humidity using wet- and dry-bulb hygrometers.

Candidate objectives

• Distinguish between saturated and unsaturated vapours.
• Relate saturated vapour pressure to boiling point.
• Determine saturated vapour pressure by the barometer tube method.
• Differentiate between dew point, humidity and relative humidity.
• Estimate atmospheric humidity using wet- and dry-bulb hygrometers.
• Solve numerical problems involving vapours and humidity.