Fundamentals

What is Thermodynamics?

Thermoynamics is the science of interaction between material and matter:

It describes how adding/removing heat or changing the chemical environment (adding/removing a solvent) changes the properties of a mixture.

 

Example:

Adding heat to water will evaporate it

Adding water to salt will dissolve it

 

Applications:

Separation of mixtures is generally based on one of the two following phenomena:

  • Evaporation: heating a mixture will make that the individual components will evaporate to a different degree depending on their respective volatilities
  • Solvation: Adding a solvent to a mixture will attract the compounds that have the highest affinity for the solvent towards this product

Activity: 

The reactivity of a compound depends on temperature, but also on its surrounding

Electrolytes are species that tend to loose or gain electrons when dissolved into a solvent (typically with a large dielectric constant, as water).

Consequences of this phenomenon are large:

 

  • Strong solubility in the solvent
  • Strong reactivity of the compound (formation of chemical complexes)
  • The activity (tendency to react) of the compound is strongly affected (e.g. corrosion…)