User:Milton Beychok/Sandbox
The meaning of gas or vapor
There is no significant physical or chemical difference between a gas and a vapor. However, the words have slightly different connotations and there is often considerable overlap between the connotations, so precise distinctions are not necessary and probably not even possible.[1][2][3][4]
Almost all physics, chemistry and engineering textbooks refer to the states of matter as solid, liquid, gas and plasma. Rarely, if ever, do the states of matter include vapor rather than gas.
One way in which the word vapor sometimes replaces the word gas is when the gaseous phase is in equilibrium with the corresponding liquid or solid. We call the pressure of the gas phase in equilibrium with the corresponding liquid phase vapor pressure. We connote the equilibrium of the gas and liquid phases of a substance as vapor-liquid equilibrium. But note that all of the connotations are defined as the equilibrium between a gas phase and a liquid phase.
The boiling point of a liquid may be defined as the temperature at which it changes its state of matter from a liquid to a gas, but we refer to that phase change as "vaporization". We also refer to the heat required to change a liquid into a gas as the heat of vaporization.
References
- ↑ Lecture by Professor Michael Mombourquette, Queens University Canada
- ↑ Richard W. Miller. Flow Measurement Engineering Handbook, Third Edition. McGraw-Hill, page 2.1. 0-07-042366-0.
- ↑ The Meaning of Vapor, Gas, Fluid by Dr. John Denker
- ↑ Vaporization: Columbia Encyclopedia, 6th Edition, 2008