Vapor pressure

Vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's thermodynamic tendency to evaporate. It relates to the balance of particles escaping from the liquid (or solid) in equilibrium with those in a coexisting vapor phase. A substance with a high vapor pressure at normal temperatures is often referred to as volatile. The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the attractive interactions between liquid molecules become less significant in comparison to the entropy of those molecules in the gas phase, increasing the vapor pressure. Thus, liquids with strong intermolecular interactions are likely to have smaller vapor pressures, with the reverse true for weaker interactions.

蒸汽压力是指在封闭系统中，在给定温度下，蒸汽与其冷凝相（固体或液体）处于热力学平衡时所施加的压力。平衡蒸汽压是液体蒸发的热力学趋势的指示。它涉及从液体（或固体）中逸出的颗粒与共存气相中的颗粒的平衡。在常温下具有高蒸气压的物质通常被称为挥发性物质。存在于液体表面上方的蒸汽所表现出的压力称为蒸汽压力。随着液体温度的升高，与气相中那些分子的熵相比，液体分子之间的吸引相互作用变得不那么显著，从而增加了蒸汽压。因此，具有较强分子间相互作用的液体可能具有较小的蒸气压，较弱的相互作用则相反。

source URL: https://en.wikipedia.org/wiki/Vapor_pressure