1. Chapter 13: Solutions

2. 13.1 Types of Solutions Mixture A blend of 2 or more kinds of matter, each of which retain its own identity & properties. Solution Solutions: homogeneous mixtures of 2 or more substances in a single phase.

3. Components of Solutions Solute – the substance being dissolved (the lemonade mix) Solvent – the substance doing the dissolving (the water) Soluble – when a substance is able to be dissolved into another substance (lemonade mix into water) Insoluble – when a substance is unable to be dissolved into another substance (oil and water)

4. Types of Solutions 1.Solid Solutions- most common are ALLOYS (a mix of 2 or more metals) 2.Gaseous Solutions – all mixtures of gases are solutions because they can all diffuse through each other. Ex: air 3.Liquid Solutions - both solvent and solute are liquids. We use the terms miscible and immiscible 4.Aqueous Solutions – when water is the solvent in the soln.

5. Suspensions & Colloids Suspension: the particles in a solvent are so large that they settle out unless the mixture is constantly stirred/agitated. Colloid: particles that are in between the size in solutions and suspensions. (colloidal dispersions)

6. Tyndall Effect Tyndall Effect- Light is dispersed by a colloidal particles in a transparent medium.

7. Solutes: Electrolytes vs. Nonelectrolytes Substances which dissolve in H 2 O are classified by what they make: Ions or molecules. Electrolytes: form ions in water and conducts currents. http://www.flixya.com/video/498469/How_To_Charge_An_IPod_Using_Electrolytes_And_An_On http://www.flixya.com/video/498469/How_To_Charge_An_IPod_Using_Electrolytes_And_An_On Nonelectrolytes: form molecules in water and does NOT conduct electricity.

8. 13.2 The Solution Process The rate at which a solid solute dissolves in a solutions depends on 3 factors: – Surface area - increase SA, increase rate of dissolving. (what dissolves faster, a block of NaCl or small flakes of NaCl?) – Stirring – by stirring, you sweep away already dissolved parts and expose new SA. – Temperature – higher the temperature the more kinetic energy, the faster the particles are moving, the faster the solid will dissolve.

9. Solubility Solution Equilibrium- when dissolution and crystallization of a solution occur at the same time.

10. Saturated vs. Unsaturated Soln.s Saturated Soln- a soln that contains the maximum amount of dissolved soulute. Unsaturated soln- a soln that contains less solute than a saturated soln contains.

11. Supersaturation! Supersaturated soln- a solution that contains MORE dissolved solute than a saturated solution under the same conditions. As the soln cools, the extra solute remains in soln and creates the supersaturated state. To encourage crystallization, uses a “seed” crystal. http://www.youtube.com/watch?v=7iNG1tTVeyA Solubility values- the amount of substance required to forms a saturated soln with a specific amount of solvent at a specified temp.

12. Solute-Solvent Interactions “Like dissolves like” is the key to understanding theses interactions. Translation: polar compounds interact with other polar compounds, & non-polar with non-polar. Dissolving ionic compound in aqueous solns- is called hydration. H 2 O is polar and will interact with ionic compounds. Ionics do not dissolve in non-polar solns.

13. Effects of pressure on Solubility Pressure does not effect solubility rates of solid and liquid solns. However, it does effect Gas solns. Increasing the pressure increases the solubility, and increases vaporization as per Le Châtelier’s principle.

14. Henry’s Law “The solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid.” Effervescence- the rapid escape of a gas from the liquid solvent.

15. Heats of Solution “The formation of a solution is accompanied by an energy change.” Exothermic- when there is a net loss (or release) of energy/heat in the system Endothermic- when there is a net gain (or absorption) of energy/heat to the system. Heat of Solution – the net amount of energy absorbed or released when a specific amount of solute dissolves is a solvent.

16. 13.3 Concentrations of Solutions Concentration- the measure of the amount of solute in a given amount of solvent or soln. Dilute: “small” amount of solute in solvent. Concentrated: “large” amount of solute in solvent.

17. Molarity – Molarity- # of moles of solute in ONE liter of solvent. Units: (mol/L) Formula: Molarity = Moles of solute ÷ liters of soln. Ex: What is the molarity of a soln. of 0.1019 mols of H 2 SO 4 with enough water to make 0.100 L of soln.?

18. Molality Molality- concentration of a soln expressed in moles of solute per kilogram of solvent. Molality = moles of solute ÷ Kg of solvent Ex: Chlorine is often added to water in swimming pools and to drinking water to keep the water free and clear of living organisms. What is the molality of 0.227 mols of Cl 2 and 5000g H 2 O?