Related Experiment Video
Updated: Jul 17, 2026
09:15
Induction of Eryptosis in Red Blood Cells Using a Calcium Ionophore
Published on: January 21, 2020
Solvent release upon ion association from entropy data. II
1Department of Inorganic and Analytical Chemistry, The Hebrew University, Jerusalem 91904, Israel. ymarcus@ vms.huji.ac.il
The Journal of Physical Chemistry. B
|January 19, 2007
Summary
Ion association releases solvent molecules, reducing overall charge and increasing entropy. This desolvation process is quantified using solvent entropy of melting, offering insights into ion pair formation.
Area of Science:
- Physical Chemistry
- Solution Chemistry
- Thermodynamics
Background:
- Ion association in solution leads to the formation of ion pairs or complexes with reduced net charge.
- Solvent molecules are released from ion solvation shells into the bulk solvent during association.
- The measurable entropy change is a sum of translational, rotational, electrostatic, and desolvation contributions.
Purpose of the Study:
- To analyze the contributions to the molar entropy change during cation-anion association.
- To quantify the desolvation entropy component by difference.
- To establish an analogy between solvent release in ion association and solvent melting.
Main Methods:
- Calculation of translational, rotational, and electrostatic entropy contributions from ion and solvent properties.
- Determination of desolvation entropy by subtracting calculated contributions from the total measurable entropy change.
- Estimation of solvent release using the molar entropy of melting of the solvent.
Main Results:
- The desolvation of ions is a significant factor contributing to the overall entropy change upon association.
- The amount of solvent released can be estimated by comparing the entropy of melting of the solvent.
- The study provides a method to quantify solvent release in various ion association scenarios (solvent-shared, contact ion pairs, inner-type complexes).
Conclusions:
- The entropy change upon ion association is significantly influenced by solvent desolvation.
- The molar entropy of melting serves as a useful proxy for estimating solvent release during ion association.
- This approach offers a quantitative understanding of solvation dynamics in ionic solutions.
Related Concept Videos
02:05Entropy and Solvation
The process of surrounding a solute with solvent is called solvation. It involves evenly distributing the solute within the solvent. The rule of thumb for determining a solvent for a given compound is that like dissolves like. A good solvent has molecular characteristics similar to those of the compound to be dissolved. For example, polar solutions dissolve polar solutes, and apolar solvents dissolve apolar solutes. A polar solvent is a solvent that has a high dielectric constant (ϵ ≥ 15); an...
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
01:17Pore Transport and Ion-Pair Transport
Pore transport and ion-pair formation are critical mechanisms for the absorption and distribution of drugs in the body.
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
03:45Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
03:24Common Ion Effect
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Châtelier’s principle. Consider the dissolution of silver iodide: