Toxins Unit

1. Toxins Unit Investigation III: Precipitating Toxins Lesson 1: Solid Evidence Lesson 2: I’ve Got My Ion You Lesson 3: Sticks and Stones Lesson 4: Blockhead Lesson 5: Mass Appeal Lesson 6: Get the Lead Out Lesson 7: Grammies

2. Toxins Unit – Investigation III Lesson 1: Solid Evidence

3. ChemCatalyst • Below is a double displacement reaction that results in the formation of one type of kidney stone. • CaCl2 (aq) + Na2C2O4 (aq)  • 2 NaCl (aq) + CaC2O4 (s) • What do you expect to see in the beaker if you complete this reaction? • Kidney stones are insoluble. Which compound is the kidney stone? Unit IV • Investigation III-X

4. The Big Question • What is a precipitation reaction and how can you determine whether a precipitate will form? Unit IV • Investigation III-X

5. You will be able to: • Use a solubility table to predict whether a particular chemical reaction will be a precipitation reaction. Unit IV • Investigation III-X

6. Notes • CaCl2 (aq) + Na2C2O4 (aq)  • 2 NaCl (aq) + CaC2O4 (s) (cont.) Unit IV • Investigation III-X

7. Notes(cont.) • Precipitate: A substance of a different phase that separates out of a solution. • A reaction in which a precipitate forms is called a precipitation reaction. (cont.) Unit IV • Investigation III-X

8. S = very soluble, N = not very soluble Unit IV • Investigation III-X

9. Activity • Purpose: In this experiment, you will predict the solubility of various ionic solids and then test your predictions. Unit IV • Investigation III-X

10. Making Sense • Write three solubility rules. (Example: Alkali metal salts tend to be soluble.) Unit IV • Investigation III-X

11. Notes • If we examine the solubility table and the results of the experiment, certain patterns emerge: • Most Group I and NH4+ salts are soluble. • Most nitrates, NO3–, salts are soluble. • Most chlorides, bromides, and iodides are soluble (except for Ag+, Pb2+, Hg2+) • Most carbonates, oxalates, and phosphates are insoluble. • Most salts of heavy metals are insoluble. (cont.) Unit IV • Investigation III-X

12. Notes (cont.) • The pros and cons of the solubility of toxins: • (Con) Things that are soluble get into the water-based systems of our bodies more easily. Once dissolved in the bloodstream they may interact in negative ways with our bodies. • (Pro) Things that are soluble are easier to filter out of the body using our natural filtration systems. (cont.) Unit IV • Investigation III-X

13. Notes(cont.) • (Con) Things that are insoluble may build up inside the body, causing blockages. • (Pro) Things that are insoluble may pass right through the body without causing harm. Unit IV • Investigation III-X

14. Check-In • A solution of K2SO4 is combined with a solution of Pb(NO3)2 and a solid forms. Write the chemical formula for the solid that formed. Unit IV • Investigation III-X

15. Wrap-Up • A precipitate is a solid produced in a chemical reaction between two solutions. • Most alkali metal compounds and most metal nitrates are soluble. Halides tend to be soluble, except for heavy metal halides. Heavy metal compounds tend to be insoluble. • Solubility can interact with the human body in either positive or negative ways. Unit IV • Investigation III-X

16. Toxins Unit – Investigation III Lesson 2: I’ve Got My Ion You

17. ChemCatalyst • Use your results from the experiments you did yesterday to write a balanced chemical reaction to describe what happens when you mix Na2CO3 (aq), sodium carbonate, with Mg(NO3)2 (aq), magnesium nitrate. Unit IV • Investigation III-X

18. The Big Question • What is the role of ions in the precipitation reaction process? Unit IV • Investigation III-X

19. You will be able to: • Predict the products of precipitation reactions and write balanced chemical equations that represent the precipitation reaction process. Unit IV • Investigation III-X

20. Activity • Purpose: This activity provides practice with equations involving ionic compounds. (cont.) Unit IV • Investigation III-X

21. (cont.) (cont.) Unit IV • Investigation III-X

22. (cont.) Unit IV • Investigation III-X

23. Making Sense • How can you predict whether you will see a solid when you dissolve a salt in water? • What patterns do you notice between charges and solubility, in question 5? Unit IV • Investigation III-X

24. Notes • To create a correct chemical equation: • The compounds must be accurately written, with atoms in the right proportions. (Check your subscripts and make sure the charges are balanced. The periodic table can help you with this step.) • The entire equation must be balanced, with the same number of each kind of atom on either side of the equation. (Count and balance.) (cont.) Unit IV • Investigation III-X

25. Notes(cont.) • The correct phase of the reactants and products must be indicated. (Check solubility rules or tables.) (cont.) Unit IV • Investigation III-X

26. Notes (cont.) • Polyatomic ion: An ion consisting of several non-metal atoms covalently bonded to one another. (cont.) Unit IV • Investigation III-X

27. Notes(cont.) • NaCl (aq) + AgNO3 (aq)  • AgCl (s) + NaNO3 (aq) (cont.) Unit IV • Investigation III-X

28. Notes(cont.) • Na+(aq) + Cl–(aq) + Ag+(aq) + NO3–(aq)  • AgCl(s) + Na+(aq) + NO3–(aq) (cont.) Unit IV • Investigation III-X

29. Notes(cont.) • Na+(aq) + Cl–(aq) + Ag+(aq) + NO3–(aq)  • AgCl(s) + Na+(aq) + NO3–(aq) (cont.) Unit IV • Investigation III-X

30. Notes(cont.) • Ag+(aq) + Cl–(aq)  AgCl(s) (cont.) Unit IV • Investigation III-X

31. Notes(cont.) • Overall ionic equation: Chemical equation written with the dissolved salts as aqueous ions. • Net ionic equation: Equation written with only those species that participate in the reaction. • Spectator ions: Ions that do not participate in the reaction. Unit IV • Investigation III-X

32. Check-In • Write a balanced chemical equation describing what happens when you mix sodium chromate and calcium nitrate. (The chromate ion is CrO42–) • Predict whether each compound should be labeled as (aq) or (s). Unit IV • Investigation III-X

33. Wrap-Up • The specific charges on ions can be deduced from the periodic table. • Some non-metal atoms remain covalently bonded as polyatomic ions. • If the charges of the cation and anion are low (e.g., +1 and –1), the compound tends to be soluble. If the charges are higher (e.g., +2 and –2 or –3), the compounds tend to be insoluble. Unit IV • Investigation III-X

34. Toxins Unit – Investigation III Lesson 3: Sticks and Stones

35. ChemCatalyst • Oxalate compounds are a common part of our daily diet. Some examples of foods that are high in oxalate are chocolate, eggplant, graham crackers, and strawberries. Too much oxalate in the body can cause kidney stones. (cont.) Unit IV • Investigation III-X

36. Notes(cont.) • Kidney stones are formed by the following precipitation reaction: • CaI2 (aq) + Na2C2O4 (aq)  • calcium iodide sodium oxalate • CaC2O4 (s) + 2 NaI (aq) • calcium oxalate sodium iodide • Do you think 1.0 g of CaI2 (aq) and 1.0 g of Na2C2O4 (aq) will produce 1.0 g of kidney stones, CaC2O4 (s)? Explain your thinking. Unit IV • Investigation III-X

37. The Big Question • What do the coefficients in a balanced chemical reaction mean, and how do they relate to real-world observations? Unit IV • Investigation III-X

38. You will be able to: • Experimentally find the highest-yielding ratios of reactants in a precipitation reaction and relate your results to the balanced chemical equation for the reaction. Unit IV • Investigation III-X

39. Activity • Purpose: You will determine what ratio of reactants gives the maximum amount of products. (cont.) Unit IV • Investigation III-X

40. (cont.) Calcium oxalate – kidney stones (cont.) Unit IV • Investigation III-X

41. (cont.) Calcium phosphate – bones Unit IV • Investigation III-X

42. Making Sense • Explain how you can use the coefficients in the balanced chemical equation to determine the ratio of reactants that will produce the maximum amount of product. Unit IV • Investigation III-X

43. Notes • A formula unit is the chemical formula that describes a substance that is not molecular. It is the simplest ratio of atoms found in the substance. For example, CaCl2 represents one formula unit of calcium chloride. Unit IV • Investigation III-X

44. Check-In • The reaction to form silver phosphate, Ag3PO4 (s) is given below: • AgNO3 (aq) + Na3PO4 (aq)  • Ag3PO4 (s) + NaNO3 (aq) (cont.) Unit IV • Investigation III-X

45. Notes(cont.) • What ratio of reactants give the maximum amount of product? • 1.0 g AgNO3 to 1.0 g Na3PO4 • 3.0 g AgNO3 to 1.0 g Na3PO4 • 1.0 moles AgNO3 to 1.0 moles Na3PO4 • 3.0 moles AgNO3 to 1.0 moles Na3PO4 Unit IV • Investigation III-X

46. Wrap-Up • The coefficients found in chemical equations stand for counting units such as number of molecules, number of moles, etc. • Coefficients in chemical equations represent the ratio in which reactants combine and products form. • Mass and volume amounts cannot be substituted for coefficients. Unit IV • Investigation III-X

47. Toxins Unit – Investigation III Lesson 4: Blockhead

48. + + ChemCatalyst • You have white, gray, and black blocks. You rearrange the pieces on the left side to give the new combinations on the right side. • 4 g 3 g 5 g (cont.) Unit IV • Investigation III-X

49. Notes(cont.) • How much does the gray block weigh? • If you have 40 g of black blocks and 30 g of white-gray pieces, how many white-black blocks can you make? Unit IV • Investigation III-X

50. The Big Question • How does the mole concept help you predict the amount of each product in a particular reaction? Unit IV • Investigation III-X