CHEM 112 Lecture Notes - Lecture 29: Vapor Pressure, Intermolecular Force, Vaporization
19 Nov 2018
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Read chapter 12-2 q"s 27, 30, 33, 34, 37, 39, 40, 44. Lecture 29: in a closed container evaporation and condensation occur at equal rates when pressure= Vapour pressure: liquids with appreciable vapor pressure at room temperature are volatile, while those with low vapour pressure are said to be non-volatile. Delta h vaporization is equal to delta h condensation. A burn from steam is a lot worse than a burn from water because we are condensing the steam also. Measuring vapour pressure: can be measured with a mercury barometer, not very precise for very low or very high vapor pressures, alternatively we can use a mercury manometer (closed or open end) or rate of effusion. How does this relate to temperature: as temperature increases the fraction of molecules with sufficient energy to break the intermolecular forces holding them in the condensed phase (liquid) increases.
