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Name: Aura
Status: student
Age: 15
Location: N/A
Country: N/A
Date: 2000


Question:
Does surface tension effect evaporation? How? Do oil and soap evaporate?


Replies:
Aura,

The surface tension of a liquid is a measure of how well the molecules in the liquid are able to hold on to each other. Thus, surface tension does affect evaporation rate.

The rather strong mutual attraction of water molecules makes for its rather large surface tension. Soaps and detergents weaken water's surface tension, thus allowing water and the cleaning agent to penetrate into the pores of soiled materials. Go here for more information ==>

http://www.newton.dep.anl.gov/askasci/gen99/gen99821.htm
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Will oil and soap evaporate?

If we define evaporation as a process in which molecules in the liquid phase move away from the liquid at the liquid-air interface and enter the gas phase, I suppose that one could say that almost anything will evaporate if given enough time. Why? It's because we can't be absolutely certain that not a single molecule of the liquid couldn't/wouldn't ever spontaneously jump off its surface. However, in practical terms, things like oil (and soap) are not very prone to evaporate. Still, something like a liquid soap left exposed to the air might get gummy from evaporative loss of water in the soap. Bar soap, on the other hand, will likely just sit there and dry out rather than evaporate.

Regards,
ProfHoff



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