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Acids and Bases

Acids and Bases. Chemistry Lowell High School 2006-2007. 2/20/07 to …. Agenda. FYI’s Reading Report Acids/Bases Preamble 8. Tuesday, February 20, 2007. FYI. RLog 16 TODAY Quiz (chap 15) 2/23 Friday QP 16 (1-49 odd) 3/2 Friday

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Acids and Bases

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  1. Acids and Bases Chemistry Lowell High School 2006-2007 2/20/07 to …

  2. Agenda • FYI’s • Reading Report • Acids/Bases • Preamble 8 Tuesday, February 20, 2007

  3. FYI • RLog 16 TODAY • Quiz (chap 15) 2/23 Friday • QP 16 (1-49 odd) 3/2 Friday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday Tuesday, February 20, 2007

  4. Important Reading Log Report • On your whiteboard, construct a reading report for chapter 16 (10 min) • Include 3 bullet points and cite section # Interconnected Interesting Incomprehensible Clarification Tuesday, February 20, 2007

  5. Acids/Bases • Acid = produces hydrogen (donor) • Base = accepts hydrogen (acceptor) • Acidity and Basicity are measured using the pH/pOH scales (range 0-14) • pH = – log [H+] pOH = – log [OH-] • pOH + pH = 14 • [H+][OH-] = 1 x 10-14 Tuesday, February 20, 2007

  6. Preamble 8 • Determine the pH of 100.0 mL of a 1.00 M HCl solution. • Suppose you double the volume of the solution by adding water. What is the new pH? You double the volume once more with water. What is the new pH? If you continue to add more water, what is the maximum pH that can be reached? Explain your answer. Tuesday, February 20, 2007

  7. Agenda • FYI’s • Acid/Base • Preamble 8 • Water’s Equilibrium • Neutralization • Preamble 9 Wednesday, February 21, 2007

  8. FYI • Quiz (chap 15) 2/23 Friday • QP 16 (1-49 odd) 3/2 Friday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday Wednesday, February 21, 2007

  9. Acids/Bases • Acid = produces hydrogen (donor) • Base = accepts hydrogen (acceptor) • Acidity and Basicity are measured using the pH/pOH scales (range 0-14) • pH = – log [H+] pOH = – log [OH-] • pOH + pH = 14 • [H+][OH-] = 1 x 10-14 Wednesday, February 21, 2007

  10. Preamble 8 • Determine the pH of 100.0 mL of a 1.00 M HCl solution. • Suppose you double the volume of the solution by adding water. What is the new pH? You double the volume once more with water. What is the new pH? If you continue to add more water, what is the maximum pH that can be reached? Explain your answer. Wednesday, February 21, 2007

  11. Water’s Equilibrium • Water is ALWAYS in equilibrium with itself according to the following equation: 2H2O H3O+ + OH- • The equilibrium constant for this reaction is called Kw = 1.0 x 10-14 • Kw = ion product constant   Wednesday, February 21, 2007

  12. Neutralization • When an acid and base are put together, they will neutralize each other. • If the acid and base contain H and OH, the reaction will form water. • H3O+ + OH- 2H2O Wednesday, February 21, 2007

  13. Preamble 9 • A Lowell student is trying to neutralize 90.0 mL of a 0.400 M solution of the strong base, Sodium hydroxide so he can put it down the drain. • He adds 30.0 mL of a 1.75 M solution of nitric acid. He then adds 240.0 mL of water. • Will the resulting solution be neutral? What will the [H+] and pH be? What is the [OH-] and pOH? Would the solution turn litmus pink? Wednesday, February 21, 2007

  14. Agenda • FYI’s • Conjugate Acid/Base • Indicators Thursday, February 22, 2007

  15. FYI • Quiz (chap 15) 2/23 Friday • QP 16 (1-49 odd) 3/2 Friday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday Thursday, February 22, 2007

  16. Conjugate Acid/Base Pairs • To find the conjugate base of an acid, remove one H • To find the conjugate acid of a base, add one H • Find the conjugate acid/base for the following: • H2SO4, C2H3O2-, NH3, HBr, NaOH Thursday, February 22, 2007

  17. Indicators • Indicators INDICATE pH via color • As the pH of the solution changes, the indicator molecule reacts to the presence of H+ by rearranging itself and forming a different color. • There is no “standard” color for each pH. Red is not always acid, blue is not always base Thursday, February 22, 2007

  18. Agenda • FYI’s • Quiz • Conjugate Acid/Base • Indicator Lab Friday, February 23, 2007

  19. FYI • Quiz (chap 15) TODAY • QP 16 (1-49 odd) 3/2 Friday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday Friday, February 23, 2007

  20. Conjugate Acid/Base Pairs • To find the conjugate base of an acid, remove one H • To find the conjugate acid of a base, add one H • Find the conjugate acid/base for the following: • H2SO4, C2H3O2-, NH3, HBr, NaOH Friday, February 23, 2007

  21. Indicator Lab Questions • Draw a color line for each of the indicators in the lab (one end = acidic, other = basic) • Compare the color lines to the ones in the book on page 520. • Why did the Bromothymol Blue solution turn yellow? What was the reaction? • What have you learned about indicators? What were some of the differences between the indicators? Friday, February 23, 2007

  22. Agenda • FYI’s • Indicator Lab Finish (10 min) • Garden Project • Buffers • Normality • Preamble 10 Monday, February 26, 2007

  23. FYI • QP 16 (1-49 odd) 3/2 Friday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday Monday, February 26, 2007

  24. Acid/Base Lab • Questions: (I saw/ I thought)1. Draw a color line for each of the indicators in the lab (one end = acidic, other = basic)2. Compare the color lines to the ones in the book on page 520. 3. Why did the Bromothymol Blue solution turn yellow? What was the reaction?4. What have you learned about indicators? What were some of the differences between the indicators? Monday, February 26, 2007

  25. Garden Project • Garden center informational brochure • Tri-fold, HANDWRITTEN/DRAWN • 4 parts that must be included • “Documents A-D” are there for your reference. You may also use web sources if you need more help • Suggestions: • Lay out a mock brochure on notebook paper before making a final version on nice paper • Use pens/markers instead of pencil for impact Monday, February 26, 2007

  26. Buffers • A buffer is a mixture of a weak acid and its conjugate base • The conjugate base is typically balanced with the presence of an alkali or alkaline earth metal (Groups 1/2) • If a base is added, it will react with the weak acid • If an acid is added, it will react with the conjugate base Monday, February 26, 2007

  27. Strong vs. Weak Acids • Strong acids: • HCl • HBr • HI • HNO3 • H2SO4 • Weak acids: • HNO2 • HF • HC2H3O2 • HCN • You will need to memorize these lists (suggestion, memorize the strong, all others are weak) Monday, February 26, 2007

  28. Normality • When an acid or a base is dissolved in water, it produces a certain amount of H+ or OH- • Normality is the concentration of H+ or OH- in the solution • Often, pH = – log N (instead of –log M) • Equivalent = amount that provides 1 mol of acid or base Monday, February 26, 2007

  29. Preamble 10 • Decide which of the following are strong vs. weak acids and write out their conjugate bases • Then, if they are weak acids, write out the reaction of a buffered solution with 1) HCl and 2) NaOH • HNO3 HF • HClO4 CH3COOH • HCl H2S Monday, February 26, 2007

  30. Agenda • FYI’s • Titration • Titration Lab Tuesday, February 27, 2007

  31. FYI • QP 16 (1-49 odd) 3/2 Friday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday Tuesday, February 27, 2007

  32. Preamble 10 • Decide which of the following are strong vs. weak acids and write out their conjugate bases • Then, if they are weak acids, write out the reaction of a buffered solution with 1) HCl and 2) NaOH • HNO3 HF • HClO4 CH3COOH • HCl H2S Tuesday, February 27, 2007

  33. Titration • Titration is a process that determines the amount/concentration of an unknown substance in a solution • The analyte = the unknown (analyzed) • The titrant = substance reacting with analyte (titrating the analyte) • In the Sailin’ the High C’s lab,Vitamin C = analyte and iodine = titrant Tuesday, February 27, 2007

  34. Titration • Titration between a strong acid and a strong base involves neutralization • H+(from acid) + OH-(from base) H2O • In this reaction, the titration is finished when the pH = 7 • The end = the equivalence point Tuesday, February 27, 2007

  35. Titration Lab • You will be given a sample with an unknown concentration of sulfuric acid (analyte). Using phenolphthalein as an indicator and sodium hydroxide as your titrant, determine the original concentration of the sulfuric acid solution. • You will be given a buret, distilled water, flasks, and graduated cylinders • Design a procedure for your experiment Tuesday, February 27, 2007

  36. Agenda • FYI’s • Extra Credit • Titration Lab • Preamble 11 Thursday, March 1, 2007

  37. FYI • QP 16 (1-49 odd) TOMORROW • Acid/Base Lab 3/5 Monday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday Thursday, March 1, 2007

  38. Extra Credit (bring 1 or 2) • 1 10lb bag of sugar • Straws (100) • box of Alka-Seltzer • Bottle of Borax • 1 large match box • Sponges • Gloves (50) M or L • Medicine cups (5) • 1 pack Food coloring • 1 box baking soda • Distilled Water (1 Gallon) • 1 25 lb bag of salt (Costco) • 1 pack of balloons (12”) (20-25/pack) • 1 hour of work after school for Ms. Rotter • Bring these supplies M-F of next week, they will apply to this marking period Thursday, March 1, 2007

  39. Acid/Base Titration Writeup • You will be doing a formal write-up for this lab. The sections that should be included are on the website. • In your lab notebook should simply be your data • The write-up (to be peer reviewed) will be due on Monday. Make sure there is a copy for each person in your team. Thursday, March 1, 2007

  40. Acid/Base Titration • Determine the concentration of the original sulfuric acid solution • What was the reaction that took place in your beaker? • What are indications that you are approaching an endpoint? • What would be the difference if you had hydrochloric acid instead of sulfuric acid? What changes would you have seen? Be specific with numbers. • Design an experiment to determine the concentration of hydroxide in an unknown sample. Thursday, March 1, 2007

  41. Preamble 11 • What ideas do you have about what happens when ice is added to water?  What happens to both the water and the ice? Use terms such as cooling, heating, melting, freezing, molecular motion/speed and energy. • Draw a series of pictures to represent what happens when ice melts into water.  Label as necessary. Thursday, March 1, 2007

  42. Agenda • FYI’s • Extra Credit • QP 16 Review Friday, March 2, 2007

  43. FYI • QP 16 (1-49 odd) TODAY • Acid/Base Lab 3/5 Monday • Garden Project 3/5 Monday (look online) • RLog 10/14 3/12 Monday • QP 10 (1-35 odd) 3/19 Monday • QP 14 (1-41 odd) 3/26 Monday • RLog 19 3/29 Thursday Friday, March 2, 2007

  44. Extra Credit (bring 1 or 2) • Gloves (50) M or L • Distilled Water (1 Gallon) • Medicine cups (5) • 1 pack Food coloring • 1 box baking soda • 1 25 lb bag of salt (Costco) • Sponges • 1 pack of balloons (12”) (20-25/pack) • 1 hour of work after school for Ms. Rotter • Bring these supplies M-F of next week, they will apply to this marking period • 1 10lb bag of sugar • Straws (100) • box of Alka-Seltzer • Bottle of Borax • 1 large match box Friday, March 2, 2007

  45. QP 16 (8 min) • On your whiteboard, put the following questions from QP 16 • Carbon Cavaliers – # 7 + 9 • Periodic Pros – # 15 + 17 • Avogadro Aces – # 21 + 29 • Kinetic Kids – # 23 + 25 • Equilibrium Experts – # 33 • Reaction Radicals – # 47 + 49 • Solubility Stars – # 43 + 45 • Valance Veterans – # 39 + 41 Friday, March 2, 2007

  46. Acid/Base Titration Writeup • You will be doing a formal write-up for this lab. The sections that should be included are on the website. • In your lab notebook should simply be your data (PLUS FIRST ANALYSIS QUESTION) • The write-up (to be peer reviewed) will be due on Monday. Make sure there is a copy for each person in your team. Friday, March 2, 2007

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