亨利定理和道尔顿定理.docx

本文格式为Word版，下载可任意编辑亨利定理和道尔顿定理 亨利定理和道尔顿定理 2022年05月29日 星期二 15:01 亨利定律Henry's law 在确定温度下，气体在液体中的饱和浓度与液面上该气体的平衡分压成正比它是英国的W.亨利于1803年在测验根基上察觉的阅历规律测验说明，只有当气体在液体中的溶解度不很高时该定律才是正确的，此时的气体实际上是稀溶液中的挥发性溶质，气体压力那么是溶质的蒸气压所以亨利定律还可表述为：在确定温度下，稀疏溶液中溶质的蒸气分压与溶液浓度成正比： pB＝kxB 式中pB是稀疏溶液中溶质的蒸气分压；xB是溶质的物质的量分数； k为亨利常数，其值与温度、压力以及溶质和溶剂的本性有关由于在稀疏溶液中各种浓度成正比，所以上式中的xB还可以是mB（质量摩尔浓度）或cB（物质的量浓度）等，此时的k值将随之变化 只有溶质在气相中和液相中的分子状态一致时，亨利定律才能适用若溶质分子在溶液中有离解、缔合等，那么上式中的 xB（或mB、cB等）应是指与气相中分子状态一致的那一片面的含量；在总压力不大时，若多种气体同时溶于同一个液体中，亨利定律可分别适用于其中的任一种气体；一般来说，溶液越稀,亨利定律愈切实，在xB→0时溶质能严格按照定律。

道尔顿气体分压定律 在任何容器内的气体混合物中，假设各组分之间不发生化学回响，那么每一种气体都平匀地分布在整个容器内，它所产生的压强和它单独占有整个容器时所产生的压强一致也就是说，确定量的气体在确定容积的容器中的压强仅与温度有关例如，零摄氏度时，1mol 氧气在 22.4L 体积内的压强是 101.3kPa 假设向容器内参与 1mol 氮气并保持容器体积不变，那么氧气的压强还是 101.3kPa，但容器内的总压强增大一倍可见， 1mol 氮气在这种状态下产生的压强也是 101.3kPa 道尔顿（Dalton）总结了这些测验事实，得出以下结论：某一气体在气体混合物中产生的分压等于它单独占有整个容 器时所产生的压力；而气体混合物的总压强等于其中各气体分压之和，这就是气体分压定律（law of partial pressure） Henry's law In chemistry, Henry's law is one of the gas laws, formulated by William Henry. It states that: At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid. Dalton's law In chemistry and physics, Dalton's law (also called Dalton's law of partial pressures) states that the total pressure exerted by a gaseous mixture is equal to the sum of the partial pressures of each individual component in a gas mixture. This empirical law was observed by John Dalton in 1801 and is related to the ideal gas laws. Mathematically, the pressure of a mixture of gases can be defined as the summation P total =P1+P2+…+Pn Where P1, P2, Pn represent the partial pressure of each component. It is assumed that the gases do not react with each other. Pi=P total Xi Where Xi = the mole fraction of the i-th component in the total mixture of m components. The relationship below provides a way to determine the volume based concentration of any individual gaseous component. Pi=P total Ci/1000000 Where, Ci is the concentration of the i-th component expressed in ppm. Dalton's law is not exactly followed by real gases. Those deviations are considerably large at high pressures. In such conditions, the volume occupied by the molecules can become significant compared to the free space between them. Moreover, the short average distance between molecules raises the intensity of intermolecular forces between gas molecules enough to substantially change the pressure exerted by them. Neither of those effects are considered by the ideal gas model. Henry's law In chemistry, Henry's law is one of the gas laws, formulated by William Henry. It states that: At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid. Formula and Henry constant A formula for Henry's Law is: where: is approximately 2.7182818, the base of the natural logarithm (also called Euler's number) is the partial pressure of the solute above the solution is the concentration of the solute in the solution (in one of its many units) is the Henry's Law constant, which has units such as L·atm/mol, atm/(mol fraction) or Pa·m3/mol. Taking the natural logarithm of the formula, gives us the more commonly used formula:[1] Some values for k include: oxygen (O2) : 769.2 L·atm/mol carbon dioxide (CO2) : 29.4 L·atm/mol hydrogen (H2) : 1282.1 L·atm/mol when these gases are dissolved in water at 298 kelvins. Note that in the above, the unit of concentration was chosen to be molarity. Hence the dimensional units: L is liters of solution, atm is the partial pressure of the gaseous solute above the solution (in atmospheres of absolute pressure), and mol is the moles of the gaseous solute in the solution. Also note that the Henry's Law constant, k, varies with the solvent and the temperature. As discussed in the next section, there are other forms of Henry's Law each of which defines the constant k differently and requires different dimensional units.[2] The form of the equation presented above is consistent with the given example numerical values for oxygen, carbon dioxide and hydrogen and with their corresponding dimensional units. [edit] Other forms of Henry's law There are various other forms Henry's Law which are discussed in the technical literature.[3][4][2] Table 1: Some forms of Henry's law and constants (gases in water at 298 K), derived from [4] equation: dimension: — 6 —。