2. Chpt 11 - Solutions Concentrations Energy of solutions Solubility Colligative Properties HW: Chpt 11 - pg. xxx-xxx, #s Due Mon Dec. 14

3. Various Types of Solutions Example State of Solution State of Solute State of Solvent Air, natural gasGas Vodka, antifreezeLiquid BrassSolid Carbonated water (soda)LiquidGasLiquid Seawater, sugar solutionLiquidSolidLiquid Hydrogen in platinumSolidGasSolid Solvent is majority component. Solute is minority component, usually the substance dissolved in the solvent (liquid).

4. Solution composition

5. Molarity You have 1.00 mol of sugar in 125.0 mL of solution. Calculate the concentration in units of molarity. 8.00 M You have a 10.0 M sugar solution. What volume of this solution do you need to have 2.00 mol of sugar? 0.200 L

6. Molarity (M) example Consider separate solutions of NaOH and KCl made by dissolving 100.0 g of each solute in 250.0 mL of solution. Calculate the concentration of each solution in units of molarity. 10.0 M NaOH 5.37 M KCl

7. Mass percent (%) What is the percent-by-mass concentration of glucose in a solution made my dissolving 5.5 g of glucose in 78.2 g of water? 6.6%

8. Mole fraction (  A ) A solution of phosphoric acid was made by dissolving 8.00 g of H 3 PO 4 in 100.0 mL of water. Calculate the mole fraction of H 3 PO 4. (Assume water has a density of 1.00 g/mL.) 0.0145

9. Molality (m) A solution of phosphoric acid was made by dissolving 8.00 g of H 3 PO 4 in 100.0 mL of water. Calculate the molality of the solution. (Assume water has a density of 1.00 g/mL.) 0.816 m

10. Solution Formation Process 1.Separating the solute into its individual components (expanding the solute). 2.Overcoming intermolecular forces in the solvent to make room for the solute (expanding the solvent). 3.Allowing the solute and solvent to interact to form the solution.

11. Solution Formation Schematic

12. Solution Formation Energies Steps 1 and 2 require energy, since forces must be overcome to expand the solute and solvent. Step 3 usually releases energy. Steps 1 and 2 are endothermic, and step 3 is often exothermic. Enthalpy change associated with the formation of the solution is the sum of the ΔH values for the steps: ΔH soln = ΔH 1 + ΔH 2 + ΔH 3 ΔH soln may have a positive sign (energy absorbed) or a negative sign (energy released).

13. Exo vs. Endo energies Demo NH 4 NO 3 and NaOH examples

14. Explain why water and oil (a long chain hydrocarbon) do not mix. In your explanation, be sure to address how ΔH plays a role. H1H1 H2H2 H3H3  H soln Outcome Polar solute, polar solvent Large Large, negative SmallSolution forms Nonpolar solute, polar solvent SmallLargeSmallLarge, positive No solution forms Nonpolar solute, nonpolar solvent Small Solution forms Polar solute, nonpolar solvent LargeSmall Large, positive No solution forms

15. Solubility Factors