1. Solutions Aqueous Solutions

2. Review How do ionic and molecular compounds differ? The molecules in molecular compounds are electrically neutral, covalently bonded groups of atoms that behave as a unit. Ionic compounds are huge collections of cations and anions.

3. Reivew What is a cation? A positive ion What is an anion? A negative ion Why are ionic compounds generally soluble in water? The cations and anions are attraced to the charged end of polar H2O molecules.

4. Solvents and Solutes Aqueous solution: A solution in which the solvent is water Solvent: The dissolving medium in a solution Solute: The dissolved particles in a solution

5. Solvents and Solutes What are some of the properties of solutions? They are stable (they don’t settle out over time) Particles/ion are less than 0.1 nanometers in diameter They cannot be separated by filtration

6. The Solution Process Solvation: A process that occurs when an ionic solute dissolves In solution, the ions are surrounded by solvent molecules What is meant by “like dissolves like?” This refers to the polarity of the compounds

8. Electrolytes and Nonelectrolytes Electrolytes: A compound that conducts an electrical current in aqueous solution or in the molten state All ionic compounds are electrolytes, but most covalent compounds are not Some polar covalent compounds form polyatomic ions when dissolved in water These compounds are electrolytes

9. Electrolytes and Nonelectrolytes Nonelectrolytes: A compound that does not conduct an electric current in aqueous solution or in the molten state Weak electrolytes: A solution in which only a fraction of the solute exists as ions. Strong electrolytes: A solution in which a large portion of the solute exists as ions.

10. Water of Hydration Water of hydration: Water molecules that are an integral part of a crystalline structure Written as (ionic formula unit)·#H 2 O The # tells you how many water molecules per ionic formula unit If the water is there it is called a hydrate. If the water is not there (when it usually is) it is called the anhydrate. The two forms often have different colors.

11. Water of Hydration Effloresce: To lose the water of hydration Hydroscopic: A term describing compounds that remove water from the air Dessicant: A hydroscopic substance used as a drying agent Deliquescent: A term describing a substance that removes enough water from the air to form a solution

12. You can use the formula of a a hydrate to calculate its percent by mass water.

13. Water of Hydration Example: Calculate the percent mass of water in Epsom salt, MgSO 4 ·7H 2 O

14. Heterogeneous Aqueous Solutions What is a heterogeneous mixture? One with different parts, like sand in water

15. Suspensions Suspensions: A mixture from which some of particles settle out slowly upon standing Muddy water The particles are about 100 nm in diameter and can be filtered out

16. Colloids Colloid: A mixture whose particles are intermediate in size between those of a suspension and a solution These cannot be filtered Jello is a colliod.

17. Colloids Dispersed phase: The particles in a colloid Usually between 0.1 nm and 100 nm in diameter Dispersing medium: The substance a colloid is made in

18. Colloids Tyndall effect: Scattering of light by particles in a colloid or suspension, which causes the beam to become visible Brownian motion: The chaotic movement of colloidal particles, caused by collision with particles of the dispersing medium

19. Colloids Emulsions: Colloids of liquids in liquids (like shaking oil and vinegar to mix them together) Adding an emulsifier makes the emulsion stable Add flour to oil and water to make gravy Add parmesan cheese to butter and cream to make Alfredo sauce Add egg yolk to oil and vinegar to make mayonnaise