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Chapter 10: Acids, Bases, and Salts

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Chapter 10: Acids, Bases, and Salts

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    1. Chapter 10: Acids, Bases, and Salts 22 March, 2012

    2. Introduction Common acids are listed in Table K, and common bases are listed in Table L of the Reference Table

    4. Introduction HCl (hydrochloric acid) is produced by the walls of our stomachs to help digest food pH of the stomach is _____?

    5. Introduction HCl (hydrochloric acid) is produced by the walls of our stomachs to help digest food pH of the stomach is 1, which is very acidic

    7. pH scale pH is a way to measure how acidic or basic a solution is Low pH values = acids High pH values = bases

    8. pH Scale pH measures the concentration of hydrogen ions = H+ If a hydrogen atoms (1 proton, 1 electron), loses its electron, what is left? So, H+ is also referred to as a proton

    9. Properties of Acids 1. Dilute acids have a sour taste (think lemons and vinegar) 2. Acids are called electrolytes, because they form ions and conduct electricity HCl ? H+ + Cl-

    11. Properties of Acids 3. Acids react with bases to form water and a salt. This is called a neutralization reaction HCl + NaOH ? H2O + NaCl Acid Base Water Salt What type of reaction is this?

    12. Properties of Acids 3. Acids react with bases to form water and a salt. This is called a neutralization reaction HCl + NaOH ? H2O + NaCl Acid Base Water Salt Double Replacement

    13. Properties of Acids Acids react with certain metals to produce hydrogen gas H2. To determine if it reacts, use table J HCl + LiOH ? react?

    14. Properties of Acids Acids react with certain metals to produce hydrogen gas H2. To determine if it reacts, use table J HCl + Li ? react? YES because Li is above/more active than hydrogen

    15. Properties of Acids 5. Acids cause acid/base indicators to change color: Table M

    16. Properties of Bases Bitter taste Slippery/soapy feeling Are also electrolytes (form ions NaOH ? Na+ + OH-

    17. Properties of Bases Bases react with acids to produce ___and____? 5. Bases cause acid-base indicators to change color

    18. Arrhenius Theory An Arrhenius acid is a substance whose water solution contains the hydrogen ion as the only positive ion

    19. Arrhenius Theory What this means is that only compounds that have H with an ionic bond, can be acids HBr ? H+ + Br- CH4 ? NO H+ IONS, because C-H bonds are ____?

    20. Arrhenius Theory What this means is that only compounds that have H with an ionic bond, can be acids HBr ? H+ + Br- CH4 ? NO H+ IONS, because C-H bonds are covalent The H is almost always the first element listed in an acid

    21. Arrhenius Theory Arrhenius was almost right Now we know that H+ in water will form the hydronium ion H+ + H2O ? H3O+ SO, acids have a high concentration of H+/H3O+ ions

    22. Bases and the hydroxide ion An Arrhenius base produces OH- when dissolved in water Mg(OH)2 ? Mg2+ + 2OH- NH3 + H2O ? NH4+ + OH-

    23. Bases and the hydroxide ion Some substances have an OH, but ARE NOT BASES CH3OH ? does not form OH ions. Why? (hint: why doesnt this form IONS?)

    24. Bases and the hydroxide ion Some substances have an OH, but ARE NOT BASES CH3OH ? does not form OH ions. Why? These are all covalent bonds When you see carbon, proceed with caution

    25. Strength of Acids and Bases HCl is a very strong acid, which can cause severe injury to human skin Citric acid is present in organges, lemons, grapefruits, etc., but is a much weaker acid

    26. Strength of Acids and Bases Another way to think about this, is how many ions are formed: When 100 molecules of HCl are put into water, 100 H+ ions are formed When 100 molecules of citric acid are put into water, only 5 H+ ions are formed

    27. Naming of Acids and Bases Binary acids: hydrogen and one other element HBr is called hydrobromic acid Hydro for the hydrogen, and bromine turns into bromic HF?

    28. Naming of Acids and Bases Binary acids: hydrogen and one other element HBr is called hydrobromic acid Hydro for the hydrogen, and bromine turns into bromic HF = hydrofluoric acid

    29. Naming of Acids and Bases Ternary acids: hydrogen and a polyatomic anion HNO3 = nitrate ion, nitric acid HNO2 = nitrite ion, nitrous acid See table 10-1

    30. Naming of Acids and Bases I ate something icky, I got an ite-ous

    31. Naming of Acids and Bases Bases are easy The name of the positive ion, and ends with hydroxide Ca(OH)2 is calcium hydroxide

    32. HW #11 Start now: Pg 177 1, 2, 4, 6, 7, 8, 9, 10 Tonight, start flash cards for Chapter 10: 10 flash cards due Monday

    33. Chapter 10 part 2 23 March, 2012

    34. Review HW#11 Pg 177 1, 2, 4, 6, 7, 8, 9, 10

    35. Remember For Monday: 10 flashcards from chapter 10 This will count as a quiz grade

    36. Review Arrhenius acids: form ___ Arrhenius bases: form _____ Neutralization reaction produces: _____and _______ H3O+ is called ____ and is formed how?

    37. Review Arrhenius acids: form ___H+ Arrhenius bases: form _____OH- Neutralization reaction produces: water and a salt H3O+ is called the hydronium ion and is formed when H+ reacts with H2O

    38. Neutralization Reactions Involve an acid and a base Nitric acid reacts with potassium hydroxide HNO3 + KOH ? KNO3 + H2O What is the salt?

    39. Neutralization Reactions Involve an acid and a base Nitric acid reacts with potassium hydroxide HNO3 + KOH ? KNO3 + H2O What is the salt? KNO3 because it is made up of a cation and an anion

    40. Neutralization Reactions In fact, both reactants form ions: H+ + NO3- + K+ + OH- ? H2O(l) + K+ + NO3- For a net ionic equation, we cancel out the ions that did not change = spectator ions

    41. Neutralization Reactions H+ + NO3- + K+ + OH- ? H2O(l) + K+ + NO3- For a net ionic equation, we cancel out the ions that did not change = spectator ions We are left with: H+ + OH- ? H2O(l)

    42. Neutralization Reactions This will be the net ionic equation for all reactions between an acid and a base Because, the salt will form ions and cancel out

    43. Neutralization Reactions Calcium hydroxide reacts with sulfuric acid Write out the chemical reaction AND the net ionic equation

    44. Ca(OH)2 + H2SO4 ? 2H2O + CaSO4 Ca2+ + 2OH- + 2H+ + SO42- ? 2H2O + Ca2+ + SO42- Ca2+ + 2OH- + 2H+ + SO42- ? 2H2O + Ca2+ + SO42- 2H+ + 2OH- ? 2H2O(l)

    45. Reactions with Acids and Metals Using Table J, will the following reactions be spontaneous? Zn + HCl ? ? Cu + HCl ? ? Ca + HCl ? ?

    46. Reactions with Acids and Metals Using Table J, will the following reactions be spontaneous? Zn + 2HCl ? Yes ? ZnCl2 + H2(g) Cu + HCl ? No Ca + 2HCl ? Yes ? CaCl2 + H2(g)

    51. HW#12 Pg 178: 11, 14, 15 Pg 181: 22, 35, 39 a and b

    52. 26 March, 2012

    53. Review HW#12 Pg 178: 11, 14, 15 Pg 181: 22, 35, 39 a and b And Flash cards

    54. Remember? Acids: H+/H3O+ ions Bases: OH- ions

    55. When an acid has more than 1 H+ to give Monoprotic acid: 1 H+ EX: HNO3 ? H+ and NO3- Diprotic acid: 2 H+ EX: H2SO4 ? 2H+ + SO42-

    56. When an acid has more than 1 H+ to give Triprotic acid: 3 H+ EX: H3PO4 ? 3H+ + PO43-

    57. When an acid has more than 1 H+ to give If the concentration of a monoprotic base is 1.5M, then the concentration of H+ is the same BUT for a diprotic acid: 1.5M H2SO4 = 3.0M H+

    58. When a base has more than 1 OH- to give 2.6M NaOH, the concentration of OH- = 2.6M 2.6M Mg(OH)2, the concentration of OH- =?

    59. When a base has more than 1 OH- to give 2.6M NaOH, the concentration of OH- = 2.6M 2.6M Mg(OH)2, the concentration of OH- =5.2M

    60. Titration A way to determine the concentration of an acid or base ALWAYS have 3 knowns and 1 unknown

    62. Titration Molarity of the acid = MA Volume of the acid = VA Molarity of the base = MB Volume of the base = VB MAVA = MBVB

    63. Titration Molarity of the KOH is 0.250M Volume of the base is 50.0mL Volume of the HCl is 20.0mL What is the molarity of the acid?

    64. MA = MBVB VA MA = 0.250M x 50.0mL 20.0mL MA = 0.625M

    65. Titration If titration involves combing an acid and a base, what type of reaction is it?

    66. Titration If titration involves combing an acid and a base, what type of reaction is it? Neutralization

    67. Acid Base Indicators In order to do a titration, you need to know when all of the acid/base has been neutralized An indicator is a chemical that changes color in response to change of H+ and/or OH-

    68. Acid Base Indicators

    69. Acid Base Indicators Methyl orange pH range: 3.1 - 4.4 Color change: red to yellow What that means is: At pH 3.1 and below, it is red Between 3.1-4.4, it is a mix of red and yellow Above pH4.4 it is yellow

    70. Acid Base Indicators Bromothymol blue At pH 6.0 and below it is yellow Between 6.0-7.6 it is a mix of yellow and blue Above pH 7.6, it is blue

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