Difference between dissolution and absorption, please advise

Absorption should involve a reaction, but dissolution does not necessarily.

The concepts are different. Dissolution refers to the process in which a solid substance enters a liquid solvent to form a solution; its fugacity is much lower than that of a gaseous substance under the same temperature and pressure. When heated, the rate at which it dissolves in the liquid solvent is much greater than the rate at which it escapes. Gas, on the other hand, does absorption always refer to gaseous substances entering a liquid solvent? . In any case, it is a process of dynamic equilibrium. Is it okay to understand it this way?

Dissolution occurs simply because a substance can dissolve in a solvent and transform from a solid state to an ionic state; it is merely a physical change. Absorption, on the other hand, involves a chemical change as new substances are formed. In the processes of mutual dissolution and absorption among solids, liquids, and gases, the main influencing factors are temperature and pressure, as well as the structure of the substance itself and the properties of the solvent. The higher the temperature, the less favorable absorption becomes; the higher the pressure, the more favorable absorption is. Most gas substances, as well as solids such as hydrogen, oxygen, calcium oxide, and calcium carbonate, absorb heat when they dissolve in water. According to the principle of equilibrium shift, when the temperature rises, the equilibrium shifts in the direction that absorbs heat. Therefore, the solubility of these substances increases as the temperature rises, such as in the case of KNO3 and NH4NO3. There are a few substances that release heat when dissolved; generally speaking, their solubility decreases as the temperature rises, such as Ca(OH)2. In other words, for substances that release heat when dissolved in water, the higher the temperature, the lower their solubility.

Dissolution: Generally refers to a solid dissolving in a liquid； Absorption: generally refers to the dissolution of a gas in a liquid ； Absorption includes physical absorption as well as chemical absorption. For ordinary substances, the higher the temperature, the more favorable it is for dissolution rather than absorption; there are also some substances whose solubility decreases as the temperature rises.

The principles of chemical engineering are explained clearly: the principle of gas absorption is that the various components in a mixed gas have different solubilities in a certain liquid, which allows the mixture of gases to be separated. (Liquid-liquid “competitive” absorption is what is commonly referred to as extraction, and it also depends on differences in solubility.) The principle of leaching is also based on the different solubilities of components in a solid within a solvent). So, the absorption process of (gases) must be a dissolution process, but not all dissolution processes are (gas) absorption. Generally, a decrease in temperature increases the solubility of gaseous solutes, which is certainly beneficial for absorption (conversely, an increase in temperature facilitates desorption). I think that in textbooks for junior and senior high school, it is presented as solids dissolving in liquids, and it is generally considered a physical reaction process; this is the narrow definition of \"dissolution\". The dissolution of gases and liquids in solvents (which can occur through chemical absorption or physical absorption, physical extraction, or chemical extraction) all fall under the concept of \"dissolution\" in a \"broader\" sense.