1 / 47

Toxins Unit – Investigation IV

Toxins Unit – Investigation IV. Lesson 1: Heartburn. 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?.

kezia
Download Presentation

Toxins Unit – Investigation IV

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Toxins Unit – Investigation IV Lesson 1: Heartburn

  2. 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

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

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

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

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

  7. (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

  8. Unit IV • Investigation IV-X

  9. 0 7 14 (cont.) (cont.) Unit IV • Investigation IV-X

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

  11. 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

  12. 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

  13. (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

  14. 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

  15. 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

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

  17. 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

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

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

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

  21. (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

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

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

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

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

  26. 0 7 14 Notes More H+ More OH– pH scale (cont.) Unit IV • Investigation IV-X

  27. (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

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

  29. 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

  30. 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

  31. 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

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

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

  34. (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

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

  36. 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

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

  38. Unit IV • Investigation IV-X

  39. HCl Unit IV • Investigation IV-X

  40. NaOH Unit IV • Investigation IV-X

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

  42. 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

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

  44. (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

  45. (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

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

  47. 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

More Related