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Acids and Bases

Acids and Bases. Some Properties of Acids. Produce H + (H 3 O + ) ions in water. The Hydronium Ion (H 3 O + ) is an H + (proton) attached to a water molecule. Taste Sour. React with certain metals to produce H 2 gas and a salt.

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Acids and Bases

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  1. Acids and Bases

  2. Some Properties of Acids • Produce H+ (H3O+) ions in water. • The Hydronium Ion (H3O+) is an H+ (proton) attached to a water molecule. • Taste Sour. • React with certain metals to produce H2 gas and a salt. • Salt – ionic-metal or a positive polyatomic ion bonded with a negative ion other than OH- • Example: MgCl2, NH4Cl • Aqueous solutions of acids conduct electricity. • Electrolytes – the greater the concentration of ions in solution, the greater the electrical conductivity. • Strong Acids & weak Acids

  3. Some Properties of Acids • React with carbonates and bicarbonates to produce carbon dioxide gas. • HCl(aq) + NaHCO3(aq) NaCl(aq) + H2O(l) + CO2(g) • React with bases to form a salt and water. • Neutralization Reaction (Double Replacement) • HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l) • pH is less than 7 • pH scale expresses the amount of H+ as a number from 0 to 14 • pH of 0 is strongly acidic and has the highest amount of H+ ions, pH of 7 is neutral, pH of 14 is strongly basic and has the fewest H+ ions. • “ABC easy as 123” • Cause acid-base indicators to change color. • Acids turn Blue litmus Red

  4. Acid Nomenclature

  5. Acid Nomenclature • Use the flowchart to name the following acids. • HBr • H2CO3 • H2SO3

  6. Acid Nomenclature

  7. Acid Nomenclature • Use the flowchart to name the following acids. • HBrHydrobromic Acid • H2CO3 Carbonic Acid • H2SO3

  8. Acid Nomenclature • Use the flowchart to name the following acids. • HBrHydrobromic Acid • H2CO3 Carbonic Acid • H2SO3 Sulfurous Acid

  9. Going Backwards… • Write H first. • Write the 2nd ion. (you may have to check table E) • Assign charges. • Criss Cross, if necessary. • Examples • Sulfuric Acid _______________________ • Nitrous Acid _______________________ • Oxalic Acid _______________________

  10. Going Backwards…Sulfuric Acid • Write H first. • Write the 2nd ion. (you may have to check table E) • -ate becomes -icgoing backwards -ic becomes -ate • -itebecomes -ousgoing backwards -ousbecomes -ite • Assign charges. • Criss Cross, if necessary.

  11. Going Backwards… • Write H first. • Write the 2nd ion. (you may have to check table E) • Assign charges. • Criss Cross, if necessary. • Examples • Sulfuric Acid _____ H2SO4__________ • Nitrous Acid _______________________ • Oxalic Acid _______________________

  12. Going Backwards… • Write H first. • Write the 2nd ion. (you may have to check table E) • Assign charges. • Criss Cross, if necessary. • Examples • Sulfuric Acid _____ H2SO4__________ • Nitrous Acid _______HNO2 __________ • Oxalic Acid ______ H2C2O4_________

  13. Name ‘Em • HI(aq) • HCl(aq) • H2SO3 • HNO3 • HClO4

  14. Name ‘Em • HI(aq) • hydroiodic Acid • HCl(aq) • hydrochloric Acid • H2SO3 • Sulfurous Acid • HNO3 • Nitric acid • HClO4 • Perchloric Acid

  15. Some Properties of Bases • Produce OH- ions in water. • Taste Bitter, chalky. • Aqueous solutions of bases conduct electricity. • Electrolytes – the greater the concentration of ions in solution, the greater the electrical conductivity. • Strong bases & weak bases • Feel soapy, slippery. • This is because they break down the normal body fat in your hands or whatever part of your body they come into contact with. • NaOH Before After

  16. Some Properties of Bases • React with acids to form a salt and water. • Neutralization Reaction (Double Replacement) • HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l) • pH is greater than 7 • pH scale expresses the amount of H+ as a number from 0 to 14 • pH of 0 is strongly acidic and has the fewest OH- ions, pH of 7 is neutral, pH of 14 is strongly basic and has the greatest amount of OH- ions. • “ABC is easy as 123” • Cause acid-base indicators to change color. • Bases turn Red litmus Blue

  17. Naming Bases • Name the Metal. • If the metal has only one possible charge, just write it’s name. • If the metal has more than one possible charge, use Roman Numerals to indicate the charge. • Follow with Hydroxide • Examples: • LiOH • Fe(OH)3

  18. Naming Bases • Name the Metal. • If the metal has only one possible charge, just write it’s name. • Li+1 = Lithium • If the metal has more than one possible charge, use Roman Numerals to indicate the charge. • Fe+2 = Iron(II) • Fe+3 = Iron (III) • Follow with Hydroxide • Lithium Hydroxide • Iron(III) Hydroxide

  19. Naming Bases • Name the Metal. • If the metal has only one possible charge, just write it’s name. • If the metal has more than one possible charge, use Roman Numerals to indicate the charge. • Follow with Hydroxide • Examples: • LiOHLithium Hydroxide • Fe(OH)3Iron(III) Hydroxide

  20. Some Common Bases • NaOH ____________________ lye • KOH ____________________ liquid soap • Ba(OH)2 ____________________ • Mg(OH)2 ____________________ • Al(OH)3 ____________________ Maalox stabilizer for plastics milk of magnesia

  21. Some Common Bases • NaOH__Sodium Hydroxide_ lye • KOH Potassium Hydroxide_ liquid soap • Ba(OH)2Barium(II) Hydroxide_ • Mg(OH)2Magnesium(II) Hydroxide • Al(OH)3Aluminum(III) Hydroxide Maalox • Table ‘L’ lists some common Bases stabilizer for plastics milk of magnesia

  22. Going Backwards… • Write the symbol of the metal. • Write OH- • Assign Charges. • Criss Cross, if necessary • Examples • Cesium Hydroxide • Chromium(III) Hydroxide • Strontium Hydroxide

  23. Going Backwards…Cesium Hydroxide • Write the symbol of the metal. • Write OH • Assign Charges • Criss Cross, if necessary

  24. Going Backwards… • Write the symbol of the metal. • Write OH- • Assign Charges. • Criss Cross, if necessary • Examples • Cesium Hydroxide CsOH • Chromium(III) Hydroxide • Strontium Hydroxide

  25. Going Backwards… • Write the symbol of the metal. • Write OH- • Assign Charges. • Criss Cross, if necessary • Examples • Cesium Hydroxide CsOH • Chromium(III) Hydroxide Cr(OH)3 • Strontium Hydroxide SrOH

  26. Practice Name each of the following… • HBr • H2SO3 • H2C2O4 • HClO • Ca(OH)2 • AgOH • HgOH • HF • HI • HClO4 • HCl • LiOH • Sn(OH)2 • Ti(OH)3

  27. Practice Name each of the following… • HBrhydrobromic acid • H2SO3sulfurous acid • H2C2O4oxalic acid • HClOhypochlorous acid • Ca(OH)2calcium(II) hdroxide • AgOHsilver hydroxide • HgOHmercury hydroxide • HF hydroflouric acid • HI hydroiodic acid • HClO4perchloric acid • HClhydrochloric acid • LiOHlithium hydroxide • Sn(OH)2tin(II) hydroxide • Ti(OH)3titanium(III) hydroxide

  28. Practice Now go backwards…. • nitric acid • carbonic acid • dichromic acid • acetic acid • nitrous acid • potassium hydroxide • cesium hydroxide • barium(II) hydroxide • aluminum(III) hydroxide • strontium(III) hydroxide

  29. Practice Now go backwards…. • nitric acid • HNO3 • carbonic acid • H2CO3 • dichromic acid • H2Cr2O7 • acetic acid • HC2H3O2 • nitrous acid • HNO2 • potassium hydroxide • KOH • cesium hydroxide • CsOH • barium(II) hydroxide • Ba(OH)2 • aluminum(III) hydroxide • Al(OH)3 • strontium(III) hydroxide • Sr(OH)3

  30. Explaining Acids and Bases • There have been several attempts to explain the properties of acids and bases. • These explanations define how acids and bases behave. • There are three such definitions. • Arrhenius Theory • Brønsted – Lowry • Lewis Acids & Bases

  31. Arrhenius Theory • Acids – produce H+ ions (or hydronium ions H3O+) as the onlypositive ion. HCl(l) Cl- + H+ • A substance with a carboxyl group(COOH) looks like a base when you look at the chemical formula but it is an acid. (Acetic Acid = HC2H3O2 = CH3COOH) CH3COOH + H2O  CH3COO- + H+

  32. Arrhenius Theory • Bases – produce OH- ions (or hydroxide ions). • Some bases DO NOT have hydroxide ions attached. • Amines – organic compounds containing C and N. Amines are bases even though they do not have an hydroxide ion. Instead they react with water to produce the OH-ion. NH3 + H2O  NH4+ + OH- ~Caution~ • Alcohols – contain an –OH but ARE NOTbases. • Example: CH3OH (hydroxyl group on a carbon chain)

  33. Types of Acids and Bases • Acids • Monoprotic: produce one H+ ion. • HCl • Diprotic: produce two H+ ions. • H2SO4 • Triprotic: produce three H+ ions. • H3PO4 • Bases • Monohydroxy: produce one OH- ion. • NaOH • Dihydroxy: produce two OH- ions. • Ba(OH)2 • Trihydroxy: produce three OH- ions. • Al(OH)3

  34. Strength of Acids and Bases Determined by the amount of Ionization. • Strong Acids • 100% dissociation in water. • Great conductors of electricity. HNO3(aq) + H2O(l) H3O+(aq) + NO3-(aq) • HI, HCl, HBr, H2SO4, and HClO4 are strong acids. • Weak Acids • Much less than 100% dissociation. • Poor conductors of electricity. CH3COOH(aq) + H2O(l) CH3COO-(aq)+ H3O+(aq) • Acetic Acid(CH3COOH)

  35. Strength of Acids and Bases Determined by the amount of Ionization. • Strong Bases • 100% dissociation (ionization) in water. • Great conductors of electricity. NaOH(aq) Na+(aq) + OH-(aq) • KOH, Ca(OH)2, Group 1 or 2 metals with hydroxide!! • Weak Bases • Much less than 100% dissociation (ionization). • Poor conductors of electricity. NH3(aq) + H2O(l) NH4+(aq)+ OH-(aq) • Ammonia (NH3)

  36. Brønsted-Lowry Acids and Bases • Acids – Proton Donors • According to the Brønsted-Lowy concept, an acid is the chemical species that donates the proton in a proton transfer reaction. • Bases – Proton Acceptors • According to the Brønsted-Lowy concept, a base is the chemical species that accepts the proton in a proton transfer reaction. A “proton” is really just a hydrogen that has lost its electron…H+

  37. Conjugate Pairs • The Brønsted-Lowry concept defines a species as an acid or a base according to its function in the proton-transfer reaction. • Consider the Reaction of NH3 + H2O • In the forward reaction, NH3 accepts a proton donated by H2O. Thus, NH3 is a base and H2O is an acid.

  38. Conjugate Pairs • In the reverse reaction, NH4+ donates a proton to OH- which accepts it. Thus, NH4+ is acid and OH- is the base.

  39. Conjugate Pairs • The species NH4+ and NH3 are a conjugate acid-base pair. • A conjugate acid-base pair consists of two species in an acid-base reaction, one acid and one base, that differ by the loss or gain of a proton. • NH4+ is the conjugate acid of NH3 • NH3 is the conjugate base of NH4+ • The species OH- and H2O are a conjugate-acid base pair as well. • OH- is the conjugate base of H2O • H2Ois the conjugate acid of OH-

  40. Conjugate Pairs

  41. Conjugate Pairs…Practice

  42. Conjugate Pairs…Practice

  43. Conjugate Pairs…Practice Problems • Label the Acid, Base, Conjugate Acid, Conjugate Base in each reaction.

  44. Conjugate Pairs…Practice Problems • Label the Acid, Base, Conjugate Acid, Conjugate Base in each reaction.

  45. Strength of Acid-Base Conjugate Pairs • Strong Acids (Proton Donors) have weak conjugate bases. • Strong Bases (Proton Acceptors) have weak conjugate acids. • Strong acids and strong bases are always on the same side of an equation. • An acid can donate it H+ to any base EXCEPT it’s conjugate base. • Example: H3PO4 can donate to F-, but not to PO43-

  46. Practice Problems • Write the conjugate base for each. • HCl ______________ • H2CrO4 ___________ • NH4+ _____________ • NH3 ______________ • Write the conjugate acid for each. • F- _________________ • H2PO4- ___________ • NH3 ______________ • HSO4- ____________

  47. Practice Problems • Write the conjugate base for each. • HCl_____Cl-_______ • H2CrO4 __CrO42-__ • NH4+ _____NH3_____ • NH3____NH2-____ • Write the conjugate acid for each. • F- ____HF____ • H2PO4-_H3PO4_ • NH3 ____NH4+ ____ • HSO4- ___H2SO4___

  48. Practice Problems • CH3COO- + H30+ CH3COOH + H2O • HCl + H2O  H3O+ + Cl- • NH2- + H2O  NH3 + OH- • H3O + OH-  H2O +H2O • CN- + H2O  HCN + OH- • HClO4 + CH3COOH  ClO4- + CH3COOH2+ • HCN + H2O  H3O+ + CN-

  49. Practice Problems Conjugate Acid Conjugate Base Base Acid • CH3COO- + H30+ CH3COOH + H2O • HCl + H2O  H3O+ + Cl- • NH2- + H2O  NH3 + OH- • H3O + OH-  H2O +H2O • CN- + H2O  HCN + OH- • HClO4 + CH3COOH  ClO4- + CH3COOH2+ • HCN + H2O  H3O+ + CN- Conjugate Acid Conjugate Base Acid Base Conjugate Acid Conjugate Base Base Acid Conjugate Acid Conjugate Base Acid Base Conjugate Acid Conjugate Base Base Acid Conjugate Acid Conjugate Base Acid Base Conjugate Acid Conjugate Base Acid Base

  50. Practice Problems • HSO4- + HCl H2SO4 +Cl- • SO42- + HNO3  HSO4- + NO3- • NH4+ + HSO4-  NH3 + H2SO4 • HCl + Al(H2O)5(OH)2+  Cl- + Al(H2O)63+ • NH3 + NH3  NH4+ + NH2-

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