1 / 34

Solutions, Acids, and Bases

Solutions, Acids, and Bases. Chapter 8. Solute The substance that is dissolved into the solution. examples: Sugar in kool-aid Salt in salt water CO 2 in pop. Solvent The substance that does the dissolving in a solution. examples: Most common is water. Parts of a solution.

abiola
Download Presentation

Solutions, Acids, and Bases

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Solutions, Acids, and Bases Chapter 8

  2. Solute The substance that is dissolved into the solution. examples: Sugar in kool-aid Salt in salt water CO2 in pop Solvent The substance that does the dissolving in a solution. examples: Most common is water. Parts of a solution

  3. Dissolving • Three ways to dissolve a solute in a solvent: • Dissociation • Dispersion • Ionization

  4. 1. Dissociation • The process in which an ionic compound separates into ions in a solution. (physical change) • Example: salt in water

  5. 2. Dispersion • Breaking the solute into small pieces and spreading throughout the solvent. • Ex. Sugar in water • Physical change

  6. 3. Ionization • The process in which neutral molecules lose or gain electrons. • Chemical change • Ex: HCl in water page 230

  7. Conductivity • Many solutions can conduct an electric current if electrolytes are present. (ions) • Electrolytes = substances that will conduct an electric current when dissolved. Ex. NaCl, KCl, MgBr2

  8. Freezing Point Depression • Lowering the freezing point of water by the addition of a solute • ex. salt. • Used on icy roads in winter • Ice-cream

  9. Boiling point elevation • The addition of a solute to a liquid solvent will usually raise the boiling point of the solvent. • Adding salt to boil water when cooking

  10. Heat of Solution • A measure of the amount of energy either absorbed or released when a solute dissolves in a solvent. • Can be endothermic or exothermic.

  11. Rate of Solution • Speed at which solute dissolves in a solvent. • 1st Stirring the solution. Helps to move the solute particles away from the solid solute.

  12. 2nd : Powdering the solute. Increases the surface area 3rd : Heating the solution. Speeds up the molecules Other factors:

  13. Concentrated A large amount of solute dissolved in a solvent Dilute A little bit of solute dissolved in a solvent Concentration

  14. Saturation • A solution that contains all the solute it can possibly hold at a given temperature is said to be saturated. • Unsaturated = contains less solute than it can possibly hold • Supersaturated = a solution that holds more solute than it should at a given temperature.

  15. Supersaturation example: • Sodium acetate in water. • Used in commercial hand warmers.

  16. Insoluble • A substance that will NOT dissolve in water.

  17. “Like dissolves like” • Nonpolar solvents will dissolve nonpolar solutes. • examples: benzene & acetone • Polar solvents will dissolve polar solutes

  18. 1.Temperature Increase in temp generally increases solubility of a solid in a liquid Increase in temp decreases solubility of a gas in a liquid. 2. Pressure Usually has little, if any, effect on solid and liquid solutes. Increase in pressure increases the solubility of a gas in a liquid. 2 factors that affect solubility:

  19. Specific concentration • Can be defined as percent by volume or percent by mass • Example: 3% hydrogen peroxide or 25% fruit juice.

  20. MOLARITY

  21. Acids • Very important chemicals in everyday life processes.

  22. Properties of acids: • Sour taste (never taste a chemical) • All contain hydrogen • Also called “proton donors” • React with active metals to produce hydrogen gas. (exp. 21) Zn + 2HCl ZnCl2 + H2

  23. Indicators • Chemicals used to identify acids and bases by changing color. • ACIDS: • Litmus paper (blue to red) • Phenolphthalein (colorless) • Methyl Orange (orange to red) • Bromothymol Blue (changes to yellow)

  24. Common acids • Sulfuric (H2SO4) used in car batteries • Nitric (HNO3) also fertilizers • Hydrochloric (HCl) stomach acid • Carbonic (H2CO3) carbonated drinks • Acetic (HC2H3O2) vinegar

  25. Also very important in everyday processes. Bases

  26. Properties of Bases: • Taste bitter; feel slippery • Contain hydroxide (OH) ions. • Known as “proton acceptors” • Phenolphthalein turns bright pink • Red litmus paper turns blue • Bromothymol blue turns blue • Methyl orange turns yellow

  27. Common bases: • Sodium hydroxide NaOH making soap; drain cleaners • Potassium hydroxide KOH battery electrolyte • Calcium hydroxide Ca(OH)2 making plaster and drywall • Magnesium hydroxide Mg(OH)2antacids

  28. Solutions of acids and bases • pH scale (page 247) • A numerical scale developed to measure the relative strengths of acids and bases • Ranges from 0 to 14 • 0 is the strongest acid • 14 is the strongest base.

  29. Always forms water and a salt. Salt = ionic compound formed when a positive ion of a base combines with a negative ion of an acid. Neutralization. These are double replacement reactions. Examples: (on board) What happens when an acid and a base combine?

  30. What determines if an acid is classified as “strong” or weak? • Which is stronger? 1 M acetic acid or 1M hydrochloric acid? • Strength is determined by how well the acid or base dissociates into solution. • Strong acids and strong bases are good electrolytes.

  31. Buffers • A mixture of a weak acid or weak base with its salt. • Resists large changes in pH. • Examples: • Bicarbonate ions in your blood stream.

  32. Assignment • Pages 257-258 • 1-10, 11, 13, 16, 20, 22, 23, 24, 27, 30, 31, 32

More Related