The Oceans Flashcards
Factors affecting relatively solubility of a solution of aqueous and non-aqueous solvents
Relatively solubility of salt determined by how strong the bonds in the solute are compared to the strength of the bonds between the solute and solvent. The solute won’t dissolve id the solute’s bonds are stronger
- Ionic solvents dissolve in polar solvents as ion-dipole bonds > ionic bonds
- > don’t dissolve in non-polar solvents as ionic bonds > dipole-ID bonds
Covalent substances dissolve in non-polar substances as covalent bonds are quite weak so ID-ID bonds are normally stronger
Hydrated ion
Ion that have water molecules bound to them
- higher charge density attracts more water
molecules so larger hydrated ion forms
- ions then behave independently
Enthalpy change of solution
Enthalpy change when one mole of a solute dissolves to form a very dilute solution
- means that if more solvent is added, the concentration doesn’t change
- ΔhydH(cation) + ΔhydH(anion) – ΔLEH
- solute (s) —> solute (aq)
-needs to be negative for something to dissolve
- if positive the process isn’t energetically
favourable
Lattice Enthalpy
Enthalpy change when one mole of a solid
is formed by the coming together of the separate ions
- always negative
- solute(g) —> solute (s)
Enthalpy change of hydration (of ions)
Enthalpy change for the formation of a solution of ions from one mole of gaseous ions
- solute (g) —> solute (aq)
- always negative
What determines Lattice Enthalpy?
As charge density increases, Lattice enthalpy becomes more negative as the ions attract each other more strongly, so more energy is released when bonds are made
Substances with a larger LE are more unlikely to dissolve as more energy must be put in
What determines Enthalpy of hydration?
Affected by charge density. As it increases the ions are more strongly attracted to the water molecules, so intermolecular bonds are strronger and more energy is released
This makes HYD more exothermic sso the solute will dissolve more easily
