1. A solution is a mixture of two or more substances, where the substance that dissolves the others is the solvent and the substances that dissolve are solutes. For example, in salt water the solvent is water and the solute is salt. 2. Solubility is affected by temperature - more solute can dissolve in hot solvents than cool solvents. At saturation, cooling a solution can cause crystals to precipitate out. 3. Electrolytes conduct electricity in solution due to dissociating into ions, while nonelectrolytes do not conduct electricity or dissociate. Electrolytes are important for functions like nerve signaling in the body.

1. SolutionsWhy Does Pasta Expand When Cooked?Why does Lemon Juice sting?Why Do Salt Grains Dissolve?

2. How Do Solutions Form?Polar molecules pull polar molecules apartWater molecules break up the salt crystals

3. Polar MoleculesSalt CrystalWater molecules attracting sodiumSome DefinitionsA solution is a mixture of 2 or more substances. The substance that dissolves the others is the SOLVENT.The substance that dissolve into the solvent are SOLUTES.Example: Salt WaterWater = Solvent Salt = Solute

5. DefinitionsSolutions can be classified as saturated or unsaturated.An unsaturated solution contains less than the maximum amount of solute.That means you can dissolve more at that particular temperature

6. DefinitionsSolutions can be classified as saturatedor unsaturated.A saturated solution contains the maximum quantity of solute that dissolves at that temperature.If it gets too saturated, crystals will form and drop out of solution.

7. How Temperature Affects SolubilityMore can dissolve in hot fluids than cool fluids.That is why you heat water to dissolve sugar or other substances into them.At cooler temperatures, the crystals will just drop to the bottom.If it is saturated and you cool it down, crystals will drop out of solution.

8. DefinitionsSUPERSATURATED SOLUTIONS contain more solute than is possible to be dissolvedSupersaturated solutions are unstableand temporaryAny disturbance, including shaking, stirring, or adding more solute will cause it to come out of solution.

9. Supersaturated Sodium AcetateOne application of a supersaturated solution is the sodium acetate “heat pack.”Click on the metal piece inside and it instantly precipitates

10. Aqueous SolutionsHow do we know ions are present in aqueous solutions?ELECTROLYTESThey conduct electricityHCl, MgCl2, and NaCl are strong electrolytes. They dissociate completely (or nearly so) into ions.

11. Aqueous SolutionsSome compounds dissolve in water but do not conduct electricity. They are called nonelectrolytes.These are usually covalent compounds, not ionicExamples include: sugar ethanol ethylene glycol

12. Electrolytes in the BodyCarry messages to and from the brain as electrical signals

13. Maintain cellular function.Changing Physical PropertiesOn adding a solute to a solvent, the properties of the solvent are modified.Vapor pressure decreasesMelting point decreasesBoiling point increasesOsmosis is possible (osmotic pressure)They depend only on the NUMBER of solute particles relative to solvent particles, not on the KIND of solute particles.

14. Change in Freezing Point Ethylene glycolPure waterThe freezing point of a solution is LOWERthan that of the pure solvent

15. Change in Freezing Point Common Applications of Freezing Point DepressionEthylene glycol – deadly to small animalsPropylene glycol

16. Properties of AcidsSour Taste

17. Litmus paper turns red

18. Reactivity with MetalsProperties of Bases Bitter Taste

19. Litmus paper turns blue

20. Slippery Feel

21. CorrosiveDefinitions:An acid is a substance that increases the H+ (or H3O+) concentration in an aqueous solution. Also known as proton donors.HCl + H2O  H++ H2O+ Cl-H3O+ + Cl- A base is a substance that increases the OH- concentrationin an aqueous solution. Also known as proton acceptors.NaOH(s)  Na+ + OH-

22. pH Scale

23. Why is Sea Water Basic?Alkaline substances such as limestone dissolve from rocks, head down rivers, and are deposited in the seaCoral, clams, snails, and others make their shells from the calcium dissolved in sea water