steps in solvation

Steps in Solvation

Endothermic- energy absorbing

Exothermic-energy releasing

Dissociation

Dissociation of Ionic Compounds

Dissociation of Covalent Compounds

Electrolytes

deionized water + NaCl

+

-

bulb

+

battery

Na+

Cl-

• When ionic compounds dissociate and a charge if applied to the solutions

When Electrolytes are Acids•Examples:

• HCl(aq) --> H+(aq) + Cl-(aq)

• HNO3(aq) --> H+(aq) + NO3-(aq)

•Acids like HCl and HNO3 are called MONOPROTIC acids since every molecule of HCl or HNO3 produces one H+

•Acids like HCl and HNO3 completely dissociate in water

•These acids are are STRONG ACIDS, and hence also strong electrolytes

Colligative Properties

Depend only on the number, not on the identity, of the solute particles in an ideal solution.

Boiling point elevation Freezing point depression Osmotic pressure

Osmotic Pressure

Osmosis: The flow of solvent into the solution through the semipermeable membrane.

Osmotic Pressure: The excess hydrostatic pressure on the solution compared to the pure solvent.

Precipitation Reactions

2 KI(aq) + Pb(NO3)2(aq) --> PbI2 (s) + 2 KNO3 (aq)

The reaction between the KI and Pb(NO3)2 results in the formation of PbI2 which has a very low solubility in water and forms a solid precipitate.

2 KI(aq) + Pb(NO3)2(aq) --> PbI2 (s) + 2 KNO3 (aq)

For compounds insoluble in water, the attraction between the oppositely charged ions in the solid crystal are too strong to be overcome by solvent water molecules.

KNO3, being soluble in water, exists in solution as K+ and NO3

- ions.