1. DAILY QUESTION November 12, 2008 1. What is “the universal solvent”?

2. Agenda11/12/08 Daily Question Check-in: Lab Wksht Ch 7 Section 2 Notes Assignments: 1. Ch 7 Sect 2 Review Wksht due 11/13

3. Water – The Universal Solvent Structure of water makes it a good solvent –Uneven distribution of electrons creates a partial positive regions by the hydrogens and a partial negative region by the oxygen –Water molecule attracts both positive and negative ions of an ionic compound This attraction pulls apart ionic compounds and “dissolves” them into solution

4. Dissolving depends on forces between particles Not all ionic compounds can be dissolved by water To dissolve a substance, solvent molecules must exert more force on the particles of the substance than the particles exert on one another

5. Hydrogen Bonding Plays a large role in dissolving molecular compounds –Attraction helps pull apart the molecules

6. Like Dissolves Like Polar compounds will dissolve polar compounds Nonpolar compounds will dissolve nonpolar compounds

7. The Dissolving Process Solutes with a larger surface area dissolve faster –Sugar cube vs. crushed crystals Stirring or shaking help solutes dissolve faster –Moving around causes more collisions Hot solvent will dissolve solutes faster –Warmer temperature causes particles to move faster, more collisions

8. Solutes affect the physical properties of a solution Raising boiling points Lowering freezing points Examples: Antifreeze in cars, Salt in ice to make ice cream