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ACIDS AND BASES

ACIDS AND BASES. CHAPTER 19 Pages 594-633. Properties of Acids. Acids have a SOUR taste Turn blue litmus paper RED Conduct electricity React with metals to produce H 2 gas (Single Replacement reaction) Form H + ions in water pH < 7.0. Acids ( continued).

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ACIDS AND BASES

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  1. ACIDS AND BASES CHAPTER 19 Pages 594-633

  2. Properties of Acids • Acids have a SOUR taste • Turn blue litmus paper RED • Conduct electricity • React with metals to produce H2 gas (Single Replacement reaction) • Form H+ ions in water • pH < 7.0

  3. Acids (continued) • React with BASES to produce a salt & H2O (aka a DOUBLE REPLACEMENT & NEUTRALIZATIONREACTION) Remember: A salt is an ionic compound, a metal and non-metal. An electrolyte is a substance which conducts electric current.

  4. ALL ACIDS MUST CONTAIN HYDROGEN

  5. Acids containing only one hydrogen are called Monoprotic, Ex: HNO3 • Acids with two hydrogens are diprotic, EX: H2SO4 & H2CO3 • Acids with 2 or more are polyprotic, EX: H3PO4

  6. ACID NOMENCLATURE • Binary- contain 2 different elements Hydrogen and one other element Binary acids begin with HYDRO Hydro+ root word of 2nd element + IC

  7. Examples of Binary Acids • HF - Hydrofluoric • HCl - Hydrochloric • HBr - Hydrobromic • HI - HydroIodic • H2S - Hydrosulfuric

  8. OXY acids • Contain OXYGEN hydrogen one other non metal

  9. OXY acid nomenclature • Named after POLYATOMIC ion they contain (…ate or …ite) RECALL: • “If I ate an acid, it would make me sick” • “Dynamite is dangerous”

  10. HERE WE GO!! • HNO3 (nitrate)HNO2 (nitrite) Nitric Nitrous • H2SO4 (sulfate) H2SO3 (sulfite) Sulfuric Sulfurous • H3PO4 (phosphateH3PO3 (phosphite) Phosphoric Phosphorous

  11. Oxyacid nomenclature …. • HC2H3O2 or CH3COOH (acetate) acetic acid when diluted it is known as vinegar • H2CO3 (carbonate) carbonic acid

  12. Arrhenius & Bronsted-Lowry Acids & Bases

  13. According to Arrhenius …. • An acid is a substance that contains hydrogen & ionizes to produce hydrogen ions (H+) in aqueous solution. • An base is a substance that contains a hydroxide group and dissociates to produce hydroxide ions (OH-) in aqueous solution.

  14. Arrhenius acid: HCl (g)→ H+(aq) + Cl-(aq) the HCl ionizes to produce H+ ions which makes the solution acidic. Arrehenius base NaOH(s) → Na+ (aq) + OH- (aq) the NaOH ionizes in water to produce OH - ions to make the solution basic.

  15. According to Bronsted-Lowry… • An acid is a hydrogen ion or proton donor • A base is a hydrogen-ion or proton acceptor

  16. Conjugate Acid Base Pairs • A conjugate acid-base pair consists of two substance related to each other by the donating and accepting of a single hydrogen ion.

  17. Let’s compare! The conjugate base is the species that results when an acid donates a hydrogen ion to a base. • The conjugate acid is the species formedwhen a base accepts a hydrogen ion from an acid.

  18. Let’s Practice • Do the practice problems on page 599 of text

  19. Strong acids • Strong acids ionize completely in water: that means that their ions remain as ions in water • Weak acids do NOT ionize completely in water: that means that their ions react to reform their acid in a reversible reaction.

  20. See page 603 for examples of strong and weak acid reactions. Notice the double arrows Indicating a reversible reaction.

  21. Strong acids do NOT produce a reversible reaction. • Weak acids DO produce a reversible reaction.

  22. Strong Acids • HCl → H+ + Cl – • H2SO4 → 2H+ + SO4-2 • HNO3 → H+ + NO3- (note only one arrow in one direction)

  23. WEAK ACIDS • Produce reversible reactions • Equilibrium reactions • H3PO4 3H+ + PO4-3 • HC2H3O2 H+ + C2H3O2- (CH3COOH) • H2CO3 2H+ + CO3-2

  24. Why Acids? Acids are important in industry and manufacturing processes. • H2SO4 -the most commonly produced chemical in the world. Used in petroleum cracking, production of dyes, fertilizers, paints, paper, detergents. Car batteries Dehydration agent (removal of H2O)

  25. HNO3 Used in making dynamite, explosives (TNT) Used in making rubber, plastics, dyes, & pharmaceuticals • H3PO4 Flavoring agent in beverages

  26. HCl - Stomach acid used in digestion process to break up and dissolve food particles & to kill unwanted bacteria Commercially used as a cleaning agent, sold at Home Depot as Muriatic Acid, used to clean brick & concrete. (This is the yellow, sour stuff when you throw up!)

  27. HC2H3O2 or CH3COOH diluted 1:10 to make vinegar A carboxyl acid, because the COOH is called a carboxyl group. It is at the end of a long chain of hydrocarbons. CH3C = O -OH

  28. Self Ionization of Water H2 O + H2 O ↔ H3O+ + OH- {H3O+} =Concentration of hydronium ions is 1 x 10-7 M {OH- } = Concentration of hydroxide ions is 1 x 10-7 M

  29. Ionization constant (K) for water • Kw = {H3O+} {OH- } = 1 x 10-14 M2 (1 x 10-7M) (1 x 10-7M) = 1 x 10-14 M2

  30. pH- • The letters “pH” originated in France and mean “the power of Hydrogen” Numerically pH is the negative of the common (base 10) logarithm of the hydronium ion. pH = - log {H3O+} pOH = -log {OH-}

  31. Practice Problem • A 1.0 x 10-4 M solution of HNO3 has been prepared for a laboratory experiment. a) Calculate the {H3O+} of this solution. b) Calculate the {OH-}.

  32. Numerically pH & pOH are the negative of the common (base 10) logarithm of the hydronium & hydroxide ions. pH = - log {H3O+} -log of 1 x 10-7 = -(-7) = 7 pOH = -log {OH-} -log of 1 x 10-7 = -(-7) = 7

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