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Q & A: pressure and boiling

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Most recent answer: 10/22/2007
Q:
why boiling point of liquid is decrease in vacuum?
- nikunj patel (age 20)
rajkot,gujarat,india
A:
A liquid boils when a bubble of its own vapor grows spontaneously. At low pressures, gas bubbles have a low density of molecules. That means that the rate at which molecules leave the bubble and join the liquid is small. So that makes it relatively easy for the molecules leaving the hot liquid to outnumber the ones joining the liquid, making the bubble grow. So you don't have to heat the liquid so much.

Mike W.

(published on 10/22/2007)

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