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Acids, Bases, & Salts

Acids, Bases, & Salts

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Acids, Bases, & Salts

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  1. Acids, Bases, & Salts

  2. Taste Sour. Can sting skin if open (cut). React with metals to produce H2 gas. Disassociate in water to produce ions that conduct electricity. (ELECTROLYTE) Acids cause indicators to change color. Properties ACIDS Blue litmus paper turns red!

  3. Taste Bitter. Feel slippery to touch. Do not react with metals. Disassociate in water to produce ions that conduct electricity. (ELECTROLYTE) Bases cause indicators to change color. Properties BASES Red litmus paper turns blue!

  4. & BASES ACIDS

  5. Neutralize each other in what is called a Neutralization Reaction. & BASES ACIDS

  6. Definitions • Arrhenius Acidsform hydrogen ions (H+) • HCl (hydrochloric acid) • HNO3 (nitric acid) • HC2H3O2 (acetic acid) • H2SO4 (sulfuric acid) • H2CO3 (carbonic acid) • H3PO4 (phosphoric acid)

  7. Definitions OH! It’s a base! • Arrhenius Basesform hydroxide ions (OH-) • NaOH (sodium hydroxide) • KOH (potassium hydroxide) • Mg(OH)2 (magnesium hydroxide) • Ca(OH)2 (calcium hydroxide) • Ba(OH)2 (barium hydroxide)

  8. Always produce a salt and water Arrhenius BASES Arrhenius ACIDS & ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H2O

  9. Arrhenius BASES Arrhenius ACIDS &

  10. Definitions • Brønsted-Lowry • Acidsare hydrogen ion (H+) donors. • Bases are hydrogen ion (H+) acceptors. HCl + H2O  Cl– + H3O+ acid base

  11. Definitions • Types of Acids: • Monoprotic Acids– have 1 proton to donate. • Diprotic Acids– have 2 protons to donate. • Triprotic Acids– have 3 protons to donate. HCl, HNO3, HF H2SO4, H2CO3, H2S H3PO4

  12. H H – + O O Cl Cl H H H H Hydronium Ion Produced when an acid dissociates in water and the water picks up the hydrogen ion. H3O+

  13. Brønsted-Lowry Acids & Bases

  14. What part does water play? H2O + HNO3 H3O+ + NO3– Base Acid

  15. What part does water play? NH3 + H2O  NH4+ + OH- Base Acid • Water is amphoteric: can act as an acid or a base.

  16. conjugate base conjugate acid Conjugate Acid – Base Pairs • When a base gains a proton, it becomes its conjugate acid. • When an acid loses a proton, it becomes its conjugate base. HCl + H2O  Cl– + H3O+ acid base

  17. Conjugate Acid – Base Pairs • Pairs are joined together by the loss and gain of a proton. • Acid & Base – Reactants side. • Conjugate Base & Conjugate Acid – Products side. NH3 + H2O  NH4+ + OH- conjugate base conjugate acid acid base

  18. Strength of Conjugate Acid-Base Pairs The stronger the acid … The weaker its conjugate base. The weaker its conjugate acid. The stronger the base …

  19. Conjugate Acid – Base Pairs

  20. Determining Strengths of Acids and Bases

  21. - + Strength • Strong Acids – Dissociate almost completely in water to produce H3O+ ions • Strong Bases – Strongly attract hydrogen ions in water, thus leaving OH- STRONG ACIDS STRONG BASES HBr HI HClO4 HCl HNO3 H2SO4 Ca(OH)2 CaO NaOH KOH

  22. - + Strength • Weak Acids – Dissociate slightly in water to produce H3O+ ions. Do not readily dissociate. • Weak Bases – react only partially with water to form OH- ions. WEAK BASES WEAK ACIDS HF CH3COOH H3PO4 CO32- PO43- NH3 H2NNH2 H2CO3 HCN

  23. HC2H3O2 + H2O HC2H3O2 + H2O H3O++ C2H3O2– H3O++ C2H3O2– SINGLE ARROW Strong Acid: HCl + H2O  H3O+ + Cl– DOUBLE ARROW Weak Acid: HC2O + H2O H3O+ + OH-

  24. SINGLE ARROW Strong Base: CaO Ca2+ + O2– O2–+ H2O 2OH– DOUBLE ARROW Weak Base: CO32-+ H2O HCO3- + OH– HC2O + H2O H3O+ + OH-

  25. Strong & Weak

  26. Acid Dissociation Constant Ka is a measure of the strength of an acid. HA(aq) + H2O (l) H3O+ (aq) + A–(aq) The greater the Ka, the stronger the acid! Ka = [H3O+][A-] [HA]

  27. If the acid is diprotic or triprotic, the loss of each hydrogen is a separate ionization. Each ionization results in a different Ka value.

  28. Base Dissociation Constant Kb is a measure of the strength of a base. B(aq)+ H2O(l) HB(aq) + OH–(aq) The greater the Kb, the stronger the base! Kb = [HB][OH-] [B]

  29. Practice Problem #1 Acetic acid is a weak monoprotic acid. If the initial concentration of acetic acid is 0.200 M and the equilibrium concentration of H3O+ is 0.0019 M, calculate Ka for acetic acid. HA(aq)+ H2O(l) H3O+(aq) + A–(aq) [H3O+][A-] Ka = [HA]

  30. Practice Problem #1 HA(aq)+ H2O(l) H3O+(aq) + A–(aq) [H3O+][A-] Ka = [H3O+] = [A-] [HA] Use Stoichiometry! The reaction produces an A- ion for every H3O+ ion.

  31. Practice Problem #1 HA(aq)+ H2O(l) H3O+(aq) + A–(aq) The equilibrium concentration of HA equals its initial concentration minus the amount that ionizes. [H3O+][A-] Ka = [HA] [HA] = 0.200M – 0.0019M [HA] = 0.1981M

  32. Practice Problem #1 HA(aq)+ H2O(l) H3O+(aq) + A–(aq) [H3O+][A-] (0.0019M)(0.0019M) Ka = = [HA] (0.1981M) [H3O+] = [A-] = 0.0019M = 1.8 x 10-5 [HA] = 0.1981M

  33. Acid-Base Properties of Salts Salts dissociate in water to form H3O+ or OH- Knowing what type of acid and base formed the salt helps predict salt solution acid-base properties.

  34. Acid-Base Properties of Salts RULES: Strong Acid + Strong Base Neutral Salt Strong Acid + Weak Base Acidic Salt Weak Acid + Strong Base Basic Salt Weak Acid + Weak Base Cannot predict very easily

  35. Neutral Salt HCl + NaOH NaCl STRONG ACID & BASE

  36. Acidic Salt NH3 + HCl NH4Cl WEAK BASE STRONG ACID

  37. Basic Salt NaOH + H2CO3 Na2CO3 STRONG BASE WEAK ACID