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Acids and Bases- 2014

Acids and Bases- 2014. Write your own notes on this powerpoint and all examples. Read chapters 14 AND 15. Acid. Base. Taste-----sour Touch stings Reacts vigourously with metals Conducts Blue litmus turns red . Taste-- bitter Touch- slippery Little reaction with metals

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Acids and Bases- 2014

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  1. Acids and Bases- 2014 Write your own notes on this powerpoint and all examples. Read chapters 14 AND 15

  2. Acid Base • Taste-----sour • Touch stings • Reacts vigourously with metals • Conducts • Blue litmus turns red Taste-- bitter Touch- slippery Little reaction with metals Conducts Red litmus turns blue

  3. There are 3 definitions of acids and bases. Each definition allows more substances to be classified as an acid or base

  4. Arrhenius Definition • Arrhenius Acid- substance that ionizes to produce H+ ions ex- HCl • Arrhenius Base- substance that dissociates to produce OH- ions ex- NaOH • Problem- must be in a water solution

  5. Lewis Definition • Uses electrons and usually deals with organic chemistry

  6. Bronsted-Lowery Definition • Acid- any substance that donates H+ • Base- any substance that accepts H+ • This definition allowed Ammonia (NH3) to be classified as a base • Water solution is NOT necessary

  7. Examples

  8. Common Acids and uses • HCl- hydrochloric acid- stomach acid and concrete cleaner • H2SO4- sulfuric acid- dehydrating agent, fertilizers • HNO3- Nitric acid- explosives H3PO4- Phosphoric Acid- soft drinks CH3COOH- Acetic Acid- vinegar

  9. Common Bases • NH3 Ammonia- cleaner • NaOH- sodium hydroxide-lye soap, drain cleaner • Mg(OH)2- Magnesium hydroxide- antacid- MOM • Calcium carbonate- antacid

  10. Bases usually contain OH- (hydroxide) but carbonates and phosphates can form basic salts • NaOH, Ca(OH)2 • Salts: CaCO3 Na3PO4 • Calcium carbonate is found in chalk, TUMS, sea shells

  11. Organic bases contain the amine functional group • (-NH2)

  12. The term alkaline refers to a base solution • Example- shampoo commercial advertises that the shampoo is a slightly alkaline (slightly basic)

  13. Relationship between Acids and Bases Conjugate Acid –Base pairs: molecules and ions that differ only by one proton (or H+1) HCN + H2O <--> H3O+1 + CN-1

  14. Acids ionize to form a H+ ion • Monoprotic- 1 ionizable H+ • Examples: HCl, HF, HBr,

  15. Diprotic Acid- contains 2 hydrogen • H2SO4 • Diprotic Acids ionize on H+1 at a time.

  16. Triprotic Acid- contains 3 hydrogens • H3PO4 Phosphoric Triprotic Acids ionize on H+1 at a time.

  17. A Binary Acid is an acid that contains hydrogen and one other element • HBr • HCl • HF • Hydro ______ic

  18. Oxyacid- an acid that contains oxygen • H2SO4 • HNO3 H3PO4

  19. Carboxylic Acid- An organic acid that will always contain the functional group -COOH • Example- Acetic Acid CH3COOH

  20. Strong Acid ionizes completely to produce strong electrolytes • HCl H+ + Cl- • HI and HBr are also strong acids (will discuss diprotic acids later)

  21. Weak Acids ionize incompletely to form weak electrolytes • HF H+ + F- • What property explains why Flourine and hydrogen refuses to break apart completely?

  22. Strong bases- break apart completely • NaOH Na+ + OH- Remember: Groups 1 and 2 except for Be and Mg

  23. Weak bases break apart incompletely • Al(OH)3 Al+3 + OH-

  24. Acid Naming rules • -ate polyatomic forms the –ic acid • Per_________ic • _________ic • _________ous • Hypo ________ous • Examples:

  25. Neutralization reaction • Acid + Base = salt + water • Sodium hydroxide + Hydrochloric Acid Salt: cation comes from the base and the anion from the acid.

  26. Sulfuric Acid + Sodium hydroxide • Carbonic Acid + Aluminum hydroxide

  27. Salts can react in neutralization rx • Hydrochloric Acid + Magnesium carbonate • Phosphoric acid + Calcium carbonate • Sulfuric Acid + Calcium carbonate  Molarity math problems

  28. Salt Prediction • Salt- a compound formed from the reaction of an acid and a base • For each salt predict the acid and base that was used: • Cation –from the base; Anion -from the acid • Sodium chloride • Magnesium phosphate • Aluminum nitrate

  29. Net Ionic • Strong Acids and Strong Bases break apart • Use this fact along with the solubility rules from the solutions chapter. • Examples:

  30. Buffers • Buffers are acids or bases that are used to prevent the pH from changing. • Bronsted-Lowery definitions for acids and bases explain buffers

  31. How buffers work • Buffers works by absorbing excess H+ or OH- in a solution. This prevents the pH from changing.

  32. Examples: • Antacids work by absorbing excess stomach acid- • They contain a buffer that prevents the stomach’s pH from changing too drastically to a basic pH

  33. Baking soda(homemade antacid) is not buffered. The pH is changed to much and the stomach releases more stomach acid and the indigestion process continues.

  34. Other common uses of buffers • Fish tanks, blood system, swimming pools

  35. Blood system—real life example • Hyperventilation- person breathes too rapidly • Too much CO2 is lost • pH of the blood increases (too basic)

  36. treatment Breathe into a bag air is rich with CO2 causes an increase in the H+ and the pH decreases back to normal

  37. Heart Failure • Person fails to release CO2 • Too much CO2 in blood system • pH of blood becomes too acidic (low pH)

  38. Treatment • IV of sodium bicarbonate(basic salt) • Increases the pH back to normal

  39. Amphoteric • A substance the can react as an acid or base depending on the chemical it is reacting with. • Examples- Al(OH)3 Water

  40. pH • Water is capable of self ionizing

  41. 1.o Liter of water produces 1.0 x 10-7 moles of H3O+ and 1.0 x 10-7 moles of OH- • This allows the Ionization constant for water to be calculated

  42. Calculate the H3O+ and the OH- • 1) .00236 M HCl 2) .0000569 M NaOH • 3) 2.69 x 10-3 M HBr 4) 4.14 x 10-11 M KOH

  43. pH is a way of expressing the hydronium ion concentration • pH scale 7 is neutral • less than 7= acid greater than 7= base

  44. Calculate the pH for the following: • .000569 M HCl 2) .00489 M HBr 3) 5.69 x 10-5 M HCl

  45. pOH is a way of expressing the hydroxide ion

  46. Calculate the pOH • 5.69 x 10-6 M NaOH • .00896 M KOH

  47. Determine the 1) hydronium 2) hydroxide • 3) pH 4) pOH • .00553 M HI • 7.23 x 10-4 M LiOH

  48. When given the pH or the pOH the H3O+ and OH- can be calculated: • H3O+ = antilog(-pH) or 10-pH • OH- = antilog (-pOH) or 10-pOH Remember the pH or pOH must be typed in as a negative number

  49. Calculate the hydronium and hydroxide ion concentration for each of the following: • 1) pH = 6.43 • 2) pOH = 3.43 • Identify if the substances are acidic ore basic

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