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Unit 8 : Acids, Bases, and Salts Topic 1: Properties of Arrhenius Acids and bases

Unit 8 : Acids, Bases, and Salts Topic 1: Properties of Arrhenius Acids and bases. I. What is an acid (Arrhenius acid?. H 2 O. To be an acid, it must be dissolved in __________ When acids are dissolved in ______________ , they ______________ and form ______________________

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Unit 8 : Acids, Bases, and Salts Topic 1: Properties of Arrhenius Acids and bases

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  1. Unit 8: Acids, Bases, and SaltsTopic 1:Properties of Arrhenius Acids and bases

  2. I. What is an acid (Arrhenius acid? H2O • To be an acid, it must be dissolved in __________ • When acids are dissolved in ______________ , they ______________ and form ______________________ • IMPORTANT: ACIDS ARE SUBSTANES THAT CONTAIN… • See Table ___ in Reference Tables for ________________ H2O BREAK APART FREELY MOVING IONS H+ IONS THAT IONIZE WHEN DISSOLVED IN WATER COMMON ACIDS K

  3. I. What is an acid (Arrhenius acid? • Example: When an acid is dissolved in water, the H+ leaves the acid and bonds to the water molecule to form a ________________________ HCl (g) + H2O (l)  H3O + (aq) + Cl- (aq) The acid HCl contains 1 H+ which combines with 1 H2O to form 1 H3O+ HYDRONIUM ION (H3O+) Dissociation of acids in water animation

  4. Ii. PROPERTIES OF ACIDS A) Acids eat away (oxidize) active metals to produce _____________________ Example: 2 Li + 2 HCl ________________ (__________________________________________) B) Acids have a __________________(we will discuss this more later on) HYDROGEN GAS 2 LiCl + H2 METAL HAS TO BE ABOVE HYDROGEN ON TABLE J pH LESS THAN 7

  5. Ii. PROPERTIES OF ACIDS ELECTROLYTES C) Acids are ________________, meaning the _______________________________________ D)Acids taste ________(like _________, but DO NOT TASTE unknown substances) CONDUCT ELECTRICITY WHEN DISSOLVED IN WATER SOUR LEMONS

  6. Iii. Weak vs. strong acids • Acids always produce H3O+ (hydronium) ions when dissolved in water. The more H+ that dissociate when in water, the stronger the acid will be. • Examples of Strong Acids – ____________________ • Example of Weak Acid – ______________ H Cl, H NO3, H Br, H I CH3CH2COOH (HC2H5O2) (organic acids) WEAK VS. STRONG ACID ANIMATION Weak vs. Strong Acid Animation #2

  7. IV. What is a Base? (Arrhenius Base) • IMPORTANT: BASES ARE SUBSTANES THAT CONTAIN… • See Table _________ in Reference Tables for ____________________ • Example: When a base is dissolved in water, the OH - 1 leaves the base NaOH (s) ______________________ OH- (Hydroxide) ions dissolved in aqueous solution. L COMMON BASES Na + 1 (aq) + OH - 1 (aq)

  8. V. Properties of bases pH above 7 • A) Bases have a _______________ (we will discuss this more later on) • B) Bases are _______________, meaning _________________________________  • C)Bases taste ______________ (like _________) • D)Bases hydrolyze fats (turns them into soap, also called “saponification”) The manufacture of soap involves heating up animal fat or vegetable oil, (for example, glycerylstearate) dissolving it in alcohol and adding NaOH or KOH to it slowly. This forms a soap (for example, sodium stearate), which can now be used for cleaning! ELECTROLYTES THEY CONDUCT ELECTRICITY WHEN DISSOLVED IN WATER BITTER SOAP/ MEDICINE

  9. VI. Strong vs. weak bases • Like acids, the more ions that dissociate in water, the stronger the base is. Bases formed with group 1 and 2 metals are typically stronger. • Examples of Strong Bases – __________________ • Example of Weak Bases – ___________________ LiOH, NaOH, Mg(OH)2 Al(OH)3, NH4OH

  10. Check for understanding • Identify the following as acids or bases • Identify it as a strong or weak acid/base 1) NaOH __________ 4) H2SO4 ___________ 2) H3BO3 __________ 5) HC2H3O2 ___________ 3) KOH __________ 6) Ca(OH)2 _________ acid (strong) base (strong) acid (strong) acid (weak) base (strong) base (strong)

  11. VII. Naming acids and bases • Naming Binary Acids (hydrogen with nonmetal): - Name the hydrogen in the acid hydro- - Name the anion and change ending of the name to –ic acid • Examples: 1. HCl (aq) - _ ____________________________ 2. HI (aq) - _____________________________ 3. HBr(aq) - ____________________________ 4. H2S(aq) - _____________________________ Hydrochloric acid Hydroiodic acid Hydrobromic acid Hydrosulfuric acid

  12. VII. Naming acids and bases • Naming Ternary Acids (hydrogen with PAI’s) • Go to Table ______ and name the PAI (polyatomic ion) • DO NOT use the prefix hydro – • If the PAI ends in - ate, it changes to –ic acid • If the PAI ends in – ite, it changes to –ous acid • Examples: 1) H2CO3 (aq) - _ ____________________________ 2) H3PO4 (aq) - _____________________________ 3) H2SO4 (aq) - _____________________________ 4) H2SO3(aq) - _____________________________ E Carbonic acid Phosphoric acid Sulfuric acid Sulfurous acid

  13. VII. Naming acids and bases • Naming Bases: - Bases are all ____________________, therefore, they are named just like ________________ • Name 1st element • Use roman numeral if the metal has more than one charge listed • 2nd half of the name will typically be _______________ • Examples: 1. NaOH (aq) - ____________________ IONIC COMPOUNDS IONIC COMPOUNDS HYDROXIDE Sodium hydroxide

  14. VII. Naming acids and bases • Naming Bases (continued): 2. Ca(OH)2 (aq) - _____________________________ 3. Fe(OH)3 (aq) - _____________________________ 4. Co(OH)2 (aq) - _____________________________ Calcium hydroxide Iron (III) hydroxide Cobalt (II) hydroxide

  15. VIII. How to know if a solution is acidic or basic a substance that changes color if an acid or base is added • Indicator –  • Acid-Base Indicators (Found on Table ___________) • Acid-Base Indicators and narrowing down pH using multiple indicators (mixture of indicators gives great range of colors, pH paper) • Remember: An acid has a pH _________________ and a base has a pH _________________ M less than 7 above 7

  16. VIII. How to know if a solution is acidic or basic • Tips Using Table M: • If the indicator changes TO the listed color, pH is ___________ the pH range. • If the indicator does NOT change, pH is __________ the pH range. • The pH range does NOT indicate that the solution has pH within that range above below

  17. Tips on using Table M • Tip 1- Notice "Common Acid Base Indicators," acid is on the left and base is on the right. • Low pH numbers are on the left and high pH numbers are on the right. They match up. • Tip 2 - Look at Methyl Orange, red is on the left, 3.2 is on the left. To the left (or below) a pH of 3.2 the color is red. • To the right (above) a pH of 4.4 the color is yellow. • Tip 3 - Between the 2 numbers will never be asked on a test. This is where the indicator changes color.

  18. VIII. How to know if a solution is acidic or basic • Example: A solution has a pH of 5.5. What color changes will happen to following indicators. 1) Methyl orange __________ 3) Bromscresol green____________ 2) Bromthylmol blue ________ 4) Thymol blue ______________ yellow blue yellow yellow

  19. VIII. How to know if a solution is acidic or basic • Example: A solution yields the following results when tested with various indicators: Methyl Orange = yellow Phenolphthalein = clear Bromcresol Green = blue Thymol Blue = yellow - Can the pH be: a) 2.8 b) 6.5 c) 8.5 d) 4.8  pH above 4.4  pH below 8.0  pH above 5.4  pH below 8 XXXX XXXX XXXX

  20. Unit 8: Acids, Bases, and SaltsTopic 2:pH SCALE

  21. IX. The Power of Hydronium (What ph really means) • The pH scale is easiest method to use for comparing the strengths of acids and bases. We test our fish tanks (fish pee out ammonia, which is a base, and brings the pH up), our lawns (acid rain brings the pH of the soil down) and even food is pH tested as it is being made to make sure that it falls within the right range. You wouldn’t want your super sour candy to have too little bite, would you? So just what is this pH, what does it mean, and how is it measured? • Water breaks up very slightly to form hydrogen ions and hydroxide ions: • H2O  H +1 + OH – 1 • In neutral water, the concentration of H + = 1.0 x 10 - 7 M, so the pH = _____ 7

  22. IX. The Power of Hydronium (What ph really means) • A pH of 0-7 is __________ When the concentration of H+ is... • A pH of 7 is ____________  10-1 M, pH = ____, 10 -2, pH =___ • A pH of 7-14 is _____________ 10 -3, pH = _____ acidic 1 2 neutral basic 3

  23. IX. The Power of Hydronium (What ph really means) • The pH scale is logarithmic. Each change of a single pH unit signifies a tenfold change in the concentration of the hydrogen ion. Therefore, the[H+] is ten times greater in a solution of pH of 5 as in a solution of pH of 6. • Examples: • A solution with pH of 3 is 10 times more acidic than solution with a pH of ____ B) A solution with pH of 3 is ___________ times more acidic than solution with a pH of 6. C) A solution with a pH of 2.0 has a hydronium ion concentration 10,000 times greater than a solution with a pH of ___________ 4 (for every power of 10, pH goes UP 1) 1,000 6

  24. IX. The Power of Hydronium (What ph really means) • The pH scale is logarithmic. Each change of a single pH unit signifies a tenfold change in the concentration of the hydrogen ion. Therefore, the[H+] is ten times greater in a solution of pH of 5 as in a solution of pH of 6. • Examples (continued): D) A sample of base has pH of 9. What would the pH of a base 1,000 more basic be? E) A sample of acid has a pH of 3. What would be the pH of an acid 100 times more acidic be? 12 (for every power of 10, the pH goes UP 1 becomes more basic) 1 (for every power of 10, the pH goes DOWN 1 becomes more acidic)

  25. IX. The Power of Hydronium (What ph really means)

  26. IX. The Power of Hydronium (What ph really means)  

  27. Think about this… • If you add a strong acid to a base, what would happen to the pH of the mixed solution? pH would decrease

  28. Unit 8: Acids, Bases, and SaltsTopic 3:acid and base neutralization

  29. X. Acid and base neutralization • Neutralization: When an acid and base are mixed, the ____________________ and the  ______________________ combine to form _______________. The anion of the acid and the cation of the base come together to form a _________________. Neutralization of Acid and Base Video Clip Double Replacement Animation Rainbow Connection Demo (Titration with pH indicators) • Salt – __________________________________________ H+ of the acid OH --- of the base Water (H2O) salt An ionic compound (metal with nonmetal/PAI) that can be formed by acid-base neutralization

  30. X. Acid and base neutralization DOUBLE REPLACEMENT REACTIONS!!! • Examples: 1) HCl (aq) + NaOH (aq)  _____ _____ ______ ___________ 2) H2SO4(aq) + 2 __________  K2SO4 (aq) + 2 _________ _______ _______ ___________ ___________ 3) 2 HNO3(aq) + __________  Ca(NO3)2 (aq) + 2 __________ _______ _______ _______ _________ HOH (l) + NaCl(aq) salt acid base water HOH(l) KOH (aq) acid salt base water Ca(OH)2 (aq) HOH (l) acid base salt water

  31. X. Acid and base neutralization • Example: Write the equation for the neutralization reaction between dilute nitric acid (HNO3) and potassium hydroxide (KOH). (DON’T FORGET TO BALANCE) 1 1 1 1 ___ HNO3( aq) + ___ KOH (aq)  ___ H(OH)(l) + ___ K(NO3)(aq) Potassium nitrate water

  32. X. Acid and base neutralization • Example: Write the equation for the neutralization reaction between dilute Mg(OH)2 and HCl. (DON’T FORGET TO BALANCE) 1 2 2 1 ___ Mg(OH)2 ( aq) + ___ HCl (aq)  ___ H(OH)(l) + ___ MgCl2(aq)

  33. Neutralization Worksheet Complete problems 1, 3, and 5 with your assigned partner. • Write the general chemical equation for a neutralization reaction: • Example: lithium hydroxide is mixed with carbonic acid.

  34. Neutralization Worksheet (answers) 1) Ba(OH)2(aq) + 2HCl(aq) BaCl2 (aq) + 2H2O(l) barium barium hydroxide + hydrochloric acid  barium chloride + water 2) 2Al(OH)3(aq) + 3H2SO4(aq) Al2(SO4)3(aq) + 6H2O(l) aluminum hydroxide + sulfuric acid  aluminum sulfate + water 3) 3Fe(OH)2(aq) + 2H3PO4(aq)  Fe3(PO4)2(aq) + 6H2O(l) iron (II) hydroxide + phosphoric acid  iron (II) phosphate + water

  35. Neutralization Worksheet (answers) 4) Ca(OH)2(aq) + 2HNO3(aq)  Ca(NO3)2(aq) + 2H2O(l) calcium hydroxide + nitric acid  calcium nitrate + water 5) 2NH4OH(aq) + H2S(aq) (NH4)2S(aq) + 2H2O(l)ammonium hydroxide+ hydrosulfuric acid ammonium sulfide + water 6) KOH(aq) + HClO2(aq) KClO2(aq) + H2O(l) potassium hydroxide + chlorous acid  potassium chlorite + water

  36. X. Titration (video demo) • Definition: process of adding a known amount of solution of known concentration to determine the concentration of another solution • moles of H+1 (aq) = moles of OH-1 (aq) • Molarity of Acid * Volume of Acid = Molarity of base * Volume of Base • Titration Equation (see Table T): Titration Animation Titration Animation #2 One mole of H + neutralizes one mole of OH -- MA(VA) = MB(VB) OR (#H+)(MA)(VA) = (#OH---)(MB)(VB)

  37. X. Titration • Example: What is the concentration of hydrochloric acid solution if 50.0 mL of a 0.250 M KOH are needed to neutralize 20.0 mL of the HCL solution of unknown concentration? (#H+)(MA)(VA) = (#OH---)(MB)(VB) #H+= 1 MA = ? MA = 0.625 M VA = 20.0 mL #OH--- = 1 MB = 0.250 M VB = 50.0 mL

  38. X. Titration • Example: What is the concentration for sulfuric acid solution if 50 mL of a 0.25 M KOH are needed to neutralize 20 mL of the sulfuric solution of unknown concentration? H2SO4 (#H+)(MA)(VA) = (#OH---)(MB)(VB) #H+= 2 MA = ? MA = 0.313 M VA = 20.0 mL #OH--- = 1 MB = 0.250 M VB = 50.0 mL

  39. X. Titration • Example: How many mL of 2.0 M H2SO4 are required to neutralize 30.0 mL of 1.0 M NaOH? (#H+)(MA)(VA) = (#OH---)(MB)(VB) #H+= 2 MA = 2.0 M VA = 7.5 mL VA = ? #OH--- = 1 MB = 1.0 M VB = 30.0 mL

  40. X. Titration • Example: How many mL of 0.10 M Ca(OH)2 are required to neutralize 25.0 mL of 0.50 M HNO3? (#H+)(MA)(VA) = (#OH---)(MB)(VB) #H+= 1 MA = 0.50 M VB = 62.5 mL VA = 25.0 mL #OH--- = 2 MB = 0.10 M VB = ??

  41. TITRATION Partner Activity With a partner and on a separate piece of paper answer question 2-12 (evens only) on pages 16-17 in the Unit 8 Work Packet. • Be sure to show ALL your work • I will collect one person’s paper from each group to grade.

  42. Unit 8: Acids, Bases, and SaltsTopic 3:pH SCALE

  43. XI. The Power of Hydronium (What ph really means) • The pH scale is easiest method to use for comparing the strengths of acids and bases. We test our fish tanks (fish pee out ammonia, which is a base, and brings the pH up), our lawns (acid rain brings the pH of the soil down) and even food is pH tested as it is being made to make sure that it falls within the right range. You wouldn’t want your super sour candy to have too little bite, would you? So just what is this pH, what does it mean, and how is it measured? • Water breaks up very slightly to form hydrogen ions and hydroxide ions: • H2O  H +1 + OH – 1 • In neutral water, the concentration of H + = 1.0 x 10 - 7 M, so the pH = _____ 7

  44. XI. The Power of Hydronium (What ph really means) • A pH of 0-7 is __________ When the concentration of H+ is... • A pH of 7 is ____________  10-1 M, pH = ____, 10 -2, pH =___ • A pH of 7-14 is _____________ 10 -3, pH = _____ acidic 1 2 neutral basic 3

  45. XI. The Power of Hydronium (What ph really means) • The pH scale is logarithmic. Each change of a single pH unit signifies a tenfold change in the concentration of the hydrogen ion. Therefore, the[H+] is ten times greater in a solution of pH of 5 as in a solution of pH of 6. • Examples: • A solution with pH of 3 is 10 times more acidic than solution with a pH of ____ B) A solution with pH of 3 is ___________ times more acidic than solution with a pH of 6. C) A solution with a pH of 2.0 has a hydronium ion concentration 10,000 times greater than a solution with a pH of ___________ 4 (for every power of 10, pH goes UP 1) 1,000 6

  46. XI. The Power of Hydronium (What ph really means) • The pH scale is logarithmic. Each change of a single pH unit signifies a tenfold change in the concentration of the hydrogen ion. Therefore, the[H+] is ten times greater in a solution of pH of 5 as in a solution of pH of 6. • Examples (continued): D) A sample of base has pH of 9. What would the pH of a base 1,000 more basic be? E) A sample of acid has a pH of 3. What would be the pH of an acid 100 times more acidic be? 12 (for every power of 10, the pH goes UP 1 becomes more basic) 1 (for every power of 10, the pH goes DOWN 1 becomes more acidic)

  47. XI. The Power of Hydronium (What ph really means)

  48. XI. The Power of Hydronium (What ph really means)  

  49. Unit 8: Acids, Bases, and SaltsTopic 4:Alternative theory of Arrhenius Acids and bases

  50. XII. Alternate Theory of Acids and Bases (Bronsted-Lowry Acids and Bases) A. Review Arrhenius Acids and Bases • Acids: ___________ ions are the only____________ ions in water • Bases: ___________ ions are the only ___________ ions in water • Bronsted-Lowry (Alternate Theory)Acids and Bases • Acids: are proton ___________________________________ • Bases: are proton ___________________________________ H + (aq) POSITIVE OH --- (aq) NEGATIVE DONORS, GIVE AWAY H+ (aq) to another substance ACCEPTORS, RECEIVE H+ (aq) from another substance

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