We are asked to explain the phenomena of how 1 gram of liquid water at 35 degrees C (as in a pond or lake) evaporating into an overlying air mass at a temp of 65 degrees C and a relative humidity of 50%.
What actually causes the evaporation of water and how can this be calculated in this instance?? What is the vapor pressure of the water??
Second, if the water contained organic contaminants such as pentachlorophenol and cresol, what are the vapor pressures of the 2 contaminants and would they evaporate before the water or would the water evaporate and leave the contaminants behind?
The solution is attached.
In the simplest terms, the vapor pressure of water is the pressure exerted by water molecules in the gas phase that come from a source of water in the liquid phase. Understand, though that this is an equilibrium situation. Molecules are becoming vapor and vapor molecules are becoming liquid at the same rate.
The process of evaporation from a pond is considered an open system, so water vapor is free to float or be blown away from the pond. When any of the vapor leaves the area of the pond, more molecules of water from the pond need to become vapor to replace the ones that left, and the process continues until the pond has evaporated.
The vapor pressure of water at 35 degrees C is 5.62 kPa,(56.2 mb) and the vapor pressure at 65 degrees is ...
Evaporation and its Effects on Pentachlorophenol and Cresol are examined in detail and evaporation calculations are performed.