Living By Chemistry

1. Living By Chemistry Unit 4: TOXINS Stoichiometry, Solution Chemistry, and Acids and Bases

2. In this unit you will learn: • how toxins are defined • how chemists determine toxicity • the mechanisms by which toxic substances act in our bodies and what this has to do with chemical reactions

3. Section I: Toxic Changes • Lesson 1 Toxic Reactions • Lesson 2 Making Predictions • Lesson 3 Spare Change • Lesson 4 Some Things Never Change • Lesson 5 Atom Inventory • Lesson 6 What’sYour Reaction?

4. Lesson 1: Toxic Reactions • Chemical Equations

5. ChemCatalyst 1. What toxins have you encountered in your life? 2. How can toxins enter the body? 3. How can toxins harm you?

6. Lesson 2: Making Predictions • Observing Change

7. ChemCatalyst • Consider this chemical equation: AgNO3(aq)  KCl(aq)  KNO3(aq)  AgCl(s) • a) What do you expect to observe if you carry out this reaction in a laboratory? • b) Write an interpretation of the chemical equation, describing what is taking place.

8. Lesson 3: Spare Change • Physical Versus Chemical Change

9. ChemCatalyst • A chunk of blue, solid cobalt (II) chloride, CoCl2, is placed into some water. The water turns from colorless to pink in color. • What type of change has taken place? How do you know? • Was something new made? Explain.

10. Lesson 4: Some Things Never Change • Conservation of Mass

11. ChemCatalyst • Consider this reaction: • a. Describe what you will observe when sodium carbonate, Na2CO3(aq), and calcium chloride, CaCl2(aq), are mixed. • b. Will the mass increase, decrease, or stay the same after mixing? Explain. Na2CO3(aq) + CaCl2(aq)  2NaCl(aq) + CaCO3(s)

12. Lesson 5: Atom Inventory • Balancing Chemical Equations

13. ChemCatalyst • Does this equation obey the law of conservation of mass? Why or why not? • CuCl2(aq) + Na2S(aq)  CuS(s) + NaCl(aq)

14. Lesson 6: What’s Your Reaction? • Types of Reactions

15. ChemCatalyst • Consider these reactions: • CaCO3(aq)  CaO(aq) + CO2(g) • CO2(g) + NaOH(aq)  NaHCO3(aq) • How are these two reactions different? • How would you describe, in words, what happens to the reactants in each case?

16. Lesson 7: Lethal Dose • Toxicity

17. ChemCatalyst • Which substance do you think is most toxic to you—alcohol (ethanol, C2H6O), aspirin (salicylic acid, C7H6O3), or arsenic (III) oxide (As2O3)? Explain your thinking.

18. Lesson 8: Make It Count • Counting By Weighing

19. ChemCatalyst • The LD50 of arsenic (III) oxide, As2O3, is 15 mg/kg. • Figure out the lethal dose for a 150 lb adult. • How many atoms do you think are in a lethal dose of arsenic (III) As2O3? What would you need to know in order to find out?

20. Lesson 9: Billions and Billions • Avogadro’s Number

21. ChemCatalyst • Which do you think is more toxic, 1 mol of arsenic, As, or 10 g of arsenic? Explain your reasoning.

22. Lesson 10: What’s in a Mole? • Molar Mass

23. ChemCatalyst • Consider 12 nickels, 2 empty aluminum cans, and a balloon full of carbon dioxide gas. • Which has the greatest mass? • Which has the greatest number of atoms? • Which has the greatest number of moles of atoms? Explain the reasoning behind your answers.

24. Lesson 11: Mountains into Molehills • Mass-Mole Conversions

25. ChemCatalyst • Arsenic, As, arsenic (III) oxide, As2O3, and arsenic (III) sulfide, As2S3, are all toxic because they contain arsenic. • Which is more toxic, 1 mol of As or 1 mol of As2O3? Explain your thinking. • Which is more toxic, 1 g of As2O3 or 1 g of As2S3? Explain.

26. Lesson 12: How Sweet It Is • Comparing Amounts

27. ChemCatalyst • Consider two cans of carbonated soft drink. One is regular, and the other is diet. • Which do you think is more toxic, the regular soft drink or the diet soft drink? Explain your reasoning • What information would help you answer this question?

28. Lesson 13: Bearly Alive • Solution Concentration

29. ChemCatalyst • Five gummy bears have been placed overnight in five different aqueous sugar solutions. Each solution contains a different amount of dissolved sugar. • Which solution do you think has the greatest amount of sugar in it? • Explain your reasoning. • What do you think caused the bears to change size?

30. Lesson 14: Drop In • Molecular Views

31. ChemCatalyst • Examine the gummy bear in the sugar solution • you prepared in class yesterday. • What does the gummy bear’s appearance suggest about the solution? • Is the solution saturated? Why or why not?

32. ChemCatalyst • Imagine that you have 1 L of a 2.0 M sugar • solution in a large container. You pour out • 100 mL into a beaker. • Did the concentration of sugar in the large container change? • Did the number of moles of sugar in the large container change?

33. Lesson 15: Holey Moley • Preparing Solutions

34. ChemCatalyst • Imagine that you want to make 5 L of0.60 M NaCl solution for a saltwater aquarium. You need to determine the correct mass of NaCl needed to obtain the correct concentration, or the fish will die. • What information do you have? • What information do you need?

35. Lesson 16: Is It Toxic? • Mystery Solutions

36. ChemCatalyst • Suppose you wanted to determine if your tap water contains lead (II) nitrate, Pb(NO3)2, which is toxic. • Do you expect the mass of 100 mL of pure water to be the same as that of a solution containing Pb(NO3)2? Explain your reasoning. • What is the molar mass of lead nitrate? What would be the mass of 0.100 mole of lead (II) nitrate?