Absorption occurs when atoms, molecules, or ions enter the bulk phase of a liquid or solid. The absorbed material is distributed within the receiving material, rather than being confined to its exterior.
Adsorption is different: adsorbed particles collect at a material's surface. The broader term sorption includes absorption, adsorption, and ion exchange.
All flashcards
What is absorption?
Absorption is the entry of atoms, molecules, or ions into the bulk phase—the interior volume—of a material.
How do absorption and adsorption differ?
Absorption distributes a substance within a material's bulk, whereas adsorption retains it at the material's surface.
What does the Nernst distribution law express for physical absorption?
At equilibrium, the ratio of a solute's concentrations in two bulk phases is constant for that solute and those phases: [x]2[x]1=KN(x,12). The partition coefficient depends on temperature.
What distinguishes chemical absorption from physical absorption?
Chemical absorption includes a reaction between the absorbed substance and the absorbing material. Physical absorption involves transfer into a phase without a chemical reaction.
What is moisture regain?
Moisture regain is the proportion of a textile material's weight made up by water. Hydrophilic fibers can lose water when heated and gradually regain it from the atmosphere.
Quiz questions
Where does a substance go during absorption?Answer: It enters the bulk phase, or interior volume, of another material.
What broad term includes absorption, adsorption, and ion exchange?Answer: Sorption.
When can physical absorption between two phases be described by the Nernst distribution law?Answer: At equilibrium, when concentrations are not too high and the solute remains in the same chemical form in both phases.
Why does carbon dioxide absorption by sodium hydroxide not generally follow the simple Nernst distribution relationship?Answer: The reaction changes the chemical species present.
A textile fiber loses mass when heated and gradually gains it again in ordinary air. What does its water content contribute to measuring?Answer: Moisture regain, the proportion of the material's weight made up by water.