1. Dissolving and Solubility
Chapter 6 Section 2 notes
Dissolving and Solubility

2. Dissolving and Solubility
The dissolving Process: 3 factors that affect solubility
Solutes with larger surface area dissolve faster. Why
When solids are whole, the particles are buried. But, when the substance is broken up, there is a larger surface area, and more collisions occur between the solute & solvent
Example: loose sugar dissolves faster than a sugar cube

3. Stirring helps a solute to dissolve faster. Why?
Stirring moves the dissolved solute away so that new solute can interact with the solvent.
Solutes dissolve faster when the solvent is hot. Why?
As a substance is heated, the particles collide more often and the solute dissolves faster.

4. Not every substance dissolves:
If a substance dissolves in water, it is soluble
If a substance doesn’t dissolve, it is insoluble
If a substance partially dissolves in water, it is partly soluble
Because water can dissolve many substances, it is said to be the universal solvent

5. The structure of a water molecule: There is 1 oxygen atom and 2 hydrogen atoms. Oxygen has a partial negative charge because oxygen attracts the electrons from hydrogen. Hydrogen has a partial positive charge. Therefore, water is a polar substance.

6. “Like Dissolves Like”: Polar substances dissolve in other polar substances. Nonpolar substances dissolve in other nonpolar substances.
Example: Water dissolves methanol but not gasoline because methanol is polar and gasoline is nonpolar.

7. Concentration: how much solute is in a solution
Dilute substance: not very much solute
Concentrated substance: a lot of solute
Unsaturated solution: a solution that can dissolve more solute
Saturated solution: a solution in which no more solute can dissolve at the given temperature
Solubility: Largest amount that will dissolve to produce a saturated solution.

8. Supersaturated solution (page 197): a solution that holds more solute than is allowed at a particular temperature.
Molarity = Moles of solute
Liters of solution
Problem: What is the molarity of a solution of sugar water if there are 9 moles of sugar and 3 liters of water?