Properties of Solutions Chapter 11 Introduction presentation

11.1 Solution Composition See Notes for all equations and related information

11.2 The energies of Solution FOrmation A. Like Dissolves Like Never forget this main rule of solution formation Polar Solvent/Polar Solute Ionic Solvent/Polar Solute Non-Polar Solvent/Non-Polar Solute

Steps of Solution Formation 1. Breaking up the solute into individual components (Expanding the solute) This is referred to as DH1 This is an endothermic process, so the enthalpy of this step is positive 2. Overcoming the intermolecular forces of the solvent to make room for the solute particles that will be entering the solution phase (Expansion of the solvent) This is referred to as DH2 This should also be an endothermic process, so the enthalpy of this step is positive and typically it is very large and very positive because the solute is typically water with hydrogen bonds

Steps continued 3. Allowing the solute and solvent to interact to form a solution This is referred to as DH3 Often this is exothermic and so the enthalpy of this step is negative Typically the more attracted to each other the solute and solvent particles are, the more negative the value of this step will be

Enthalpy (Heat) of Solution (hydration) DHsoln = DH1 + DH2 + DH3 If the final value is a positive number, energy is absorbed during the process and its an endothermic process If the final value is a negative number, energy is released during the process, and its an endothermic process If the Enthalpy of solution is small or negative than its likely that your solution will form If the Enthalpy of solution is large and positive, your solution is not forming If its small and positive then we need to examine the component parts and check our solubility rules

11.3 Factors A. Influence of Structure – See Notes B. Pressure Effects – See Notes C. Temperature Effects – See Notes