The discussion revolves around the relationship between external pressure applied to a liquid and its vapor pressure, exploring theoretical concepts from chemistry and thermodynamics. Participants examine how hydrostatic pressure influences the tendency of solvent molecules to escape from the liquid phase into the vapor phase, considering various factors such as Gibbs free energy and the Poynting correction.
Participants do not reach a consensus on the relationship between external pressure and vapor pressure, with multiple competing views and ongoing confusion about the underlying principles.
Participants reference specific thermodynamic equations and concepts, but there are indications of varying levels of familiarity with these topics, leading to questions about their implications and applications.
This discussion may be of interest to students and individuals studying chemistry, thermodynamics, or related fields, particularly those exploring phase transitions and the effects of pressure on vapor pressure.
The boiling point is defined as the temperature where the vapour pressure is equal to external pressure. So it will always rise with pressure.realitysickness said:Hi DrDu, do you mind responding to my earlier question: "My only question remains then: given the information you just stated, for situations where temperature is not a constant, why are the boiling point temperatures of a liquid higher at higher pressures?
No, it does not. Ideal gases don't know of each other. So when in the gas phase, the energy of the vapour will only depend on temperature, but not on pressure. The energy of the liquid on the other hand is slightly increased due to compression. So the energy a molecule needs to go from the liquid to the gas phase decreases. For real gases there are slight deviations from ideality at high pressures, but these are weaker than the energy change due to pressure of the liquid.OldYat47 said:Increasing the pressure in a gaseous atmosphere above a liquid increases the amount of energy needed for individual molecules to escape to a vapor state. The first effect is much smaller than the second.