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Toxins Unit

Toxins Unit. Investigation IV: Neutralizing Toxins. Lesson 1: Heartburn. Lesson 2: Watered Down. Lesson 3: pHooey!. Lesson 4: Proton Shuffle. Lesson 5: Neutral Territory. Lesson 6: Drip Drop. Lesson 7: Call Poison Control. Toxins Unit – Investigation IV. Lesson 1: Heartburn.

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Toxins Unit

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  1. Toxins Unit Investigation IV: Neutralizing Toxins Lesson 1: Heartburn Lesson 2: Watered Down Lesson 3: pHooey! Lesson 4: Proton Shuffle Lesson 5: Neutral Territory Lesson 6: Drip Drop Lesson 7: Call Poison Control

  2. Toxins Unit – Investigation IV Lesson 1: Heartburn

  3. ChemCatalyst • Countless products are advertised on TV with the promise of reducing acid indigestion. • What is acid indigestion? What is acidity? • What does acid have to do with your stomach? • How do you think acid “reducers” work? Unit IV • Investigation IV-X

  4. The Big Question • What are some characteristics of solutions that are acidic, basic, or neutral? Unit IV • Investigation IV-X

  5. You will be able to: • Describe the differences among acidic, basic, and neutral solutions. Unit IV • Investigation IV-X

  6. Notes • Indicators: A set of substances that respond to other substances with vivid color changes. Unit IV • Investigation IV-X

  7. Activity • Purpose: This activity will introduce you to a special category of solution. (cont.) Unit IV • Investigation IV-X

  8. (cont.) • Safety note: Do not get acids and bases on your skin. In case of a spill, rinse with large amounts of water. Wear goggles. (cont.) Unit IV • Investigation IV-X

  9. Unit IV • Investigation IV-X

  10. 0 7 14 (cont.) (cont.) Unit IV • Investigation IV-X

  11. (cont.) Unit IV • Investigation IV-X

  12. Making Sense • Look for patterns in the names, chemical formulas, uses, and properties of the substances you tested. • List four characteristics of acids. • List four characteristics of bases. Unit IV • Investigation IV-X

  13. Notes • Indicators can be used to identify substances that are acidic, basic, and neutral when dissolved in water. • Acids turn cabbage juice pink and are between 0 and 7 on the universal indicator scale. • Bases turn cabbage juice green or blue and are between 7 and 14 on the universal indicator scale. • Neutral substances do not change color with cabbage juice and are at or very near 7 on the universal indicator scale. (cont.) Unit IV • Investigation IV-X

  14. (cont.) • pH scale: A number line from 0 to 14. The numbers are associated with indicator colors. • The numbers associated with indicator colors are also called pH numbers or simply pH. Unit IV • Investigation IV-X

  15. Check-In • An unknown substance is purple with cabbage juice and does not react with calcium carbonate. Is it an acid, base or neutral substance? Explain. Unit IV • Investigation IV-X

  16. Wrap-Up • Acids and bases are different types of solutions and are classified according to their observable behavior. • Acids and bases respond differently to indicators. Depending on the indicator, different colors will form that show either an acidic or basic substance. Unit IV • Investigation IV-X

  17. Toxins Unit – Investigation IV Lesson 2: Watered Down

  18. ChemCatalyst • Describe what you observe in the three vials. • What is one explanation for the differences you observe? • If you tested each solution with universal indicator before putting in the gummy bears, what colors would you expect to see? Unit IV • Investigation IV-X

  19. The Big Question • How does dilution affect the acidity or basicity of a solution? Unit IV • Investigation IV-X

  20. You will be able to: • Explain how dilution affects the concentration and pH of a solution. Unit IV • Investigation IV-X

  21. Activity • Purpose: In this activity you will examine the effect of concentration on acidity and basicity of solutions. (cont.) Unit IV • Investigation IV-X

  22. (cont.) • Safety note – Do not get acids and bases on your skin. In case of a spill, rinse with large amounts of water. Wear goggles. (cont.) Unit IV • Investigation IV-X

  23. Data Table for dilution of 1.0 M HCl Unit IV • Investigation IV-X

  24. Data Table for dilution of 1.0 M NaOH Unit IV • Investigation IV-X

  25. Data Table for dilution of 1.0 M NaCl Unit IV • Investigation IV-X

  26. Making Sense • What does concentration have to do with the acidity or basicity of a solution? Unit IV • Investigation IV-X

  27. 0 7 14 Notes More H+ More OH– pH scale (cont.) Unit IV • Investigation IV-X

  28. (cont.) • Arrhenius definition: • An acid is any substance that adds a hydrogen ion (H+) to the solution. • A base is any substance that adds a hydroxide ion (OH–) to the solution. (cont.) Unit IV • Investigation IV-X

  29. (cont.) • HA  H+ + A– • XOH  X+ + OH– Unit IV • Investigation IV-X

  30. Check-In • Lemon juice has a pH of about 2. What does this tell you about what is in the solution? • What would happen if you diluted this solution? Unit IV • Investigation IV-X

  31. Wrap-Up • The acidity and basicity of a solution are related to the concentration of the solution. Dilute solutions are less acidic and basic than more concentrated solutions. • Dilution of an acid or a base results in a solution that is increasingly neutral. (cont.) Unit IV • Investigation IV-X

  32. The pH scale is related to the concentration of H+ and OH– ions in solution. • According to Arrhenius, an acid is any substance that adds a hydrogen ion (H+) to the solution and a base is any substance that adds a hydroxide ion (OH–) to the solution. Unit IV • Investigation IV-X

  33. Toxins Unit – Investigation IV Lesson 3: pHooey!

  34. ChemCatalyst • Examine the following data: (cont.) Unit IV • Investigation IV-X

  35. (cont.) • What do you think pH really represents? • How does the concentration of the solutions relate mathematically to the pH of the solutions? Unit IV • Investigation IV-X

  36. The Big Question • How does pH relate to the concentrations of acidic and basic solutions? Unit IV • Investigation IV-X

  37. You will be able to: • Find the pH of a solution if you know the concentrations of hydrogen or hydroxide ions that it contains. Unit IV • Investigation IV-X

  38. Activity • Purpose: You will explore the relationship between pH, pOH, [H+], and [OH–]. (cont.) Unit IV • Investigation IV-X

  39. Unit IV • Investigation IV-X

  40. HCl Unit IV • Investigation IV-X

  41. NaOH Unit IV • Investigation IV-X

  42. Making Sense • How are pH and pOH related to each other mathematically? Unit IV • Investigation IV-X

  43. Notes pH = 4 pH = 5 pH = 6 pH = 7 This box would show 1,000 H+ ions and 1,000 Cl– ions. This box would show 100 H+ ions and 100 Cl– ions. (cont.) Key: H+ Cl– Unit IV • Investigation IV-X

  44. (cont.) • pH = –log[H+] • pOH = –log[OH–] (cont.) Unit IV • Investigation IV-X

  45. (cont.) • Sample Problem: • What is the pH of a solution with a hydrogen ion concentration of 3.4  10–4 moles/ L? (cont.) Unit IV • Investigation IV-X

  46. (cont.) • Please be careful when entering scientific notation into your calculator—it is very easy to make a mistake. When entering 3.4  10–4, first enter “3.4”. Then press the button labeled “EXP” or “10X” or “EE”. Now enter –4, using the “+/–“ key, not the subtraction key. Never try to enter this number by pressing “X” and “10” and “–4”. Unit IV • Investigation IV-X

  47. Check-In • What is the pH of a solution with [OH–] = 1.0  10–12 M? Unit IV • Investigation IV-X

  48. Wrap-Up • The relationship between pH and pOH of a solution is expressed by the following: pH + pOH = 14. • The relationship between [H+] and [OH–] in a solution is expressed by the following: –log [H+] + –log [OH–] = 14. • The pH of a solution is logarithmically related to the concentration of hydrogen ion and can be calculated mathematically using the following equation: pH = log [H+] Unit IV • Investigation IV-X

  49. Toxins Unit – Investigation IV Lesson 4: Proton Shuffle

  50. ChemCatalyst • Besides HCl, the digestive system also produces a compound called bicarbonate, HCO3–. Bicarbonate plays a vital role in regulating the pH of the digestive system. • Do you think bicarbonate, HCO3–, is an acidic, basic or neutral substance? Explain your reasoning. Unit IV • Investigation IV-X

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