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  1. Toxins Unit Investigation I: Dissolving Toxins Lesson 1: Lethal Dose Lesson 2: Bearly Alive Lesson 3: Mixing It Up! Lesson 4: Weighing In Lesson 5: Finding Solutions Lesson 6: Holey Moley Lesson 7: Is It Toxic?

  2. Toxins Unit – Investigation I Lesson 1: Lethal Dose

  3. ChemCatalyst • Which substance do you think is most toxic to you – alcohol (ethanol, C2H6O), aspirin (salicylic acid, C7H6O3), or arsenic (As)? Explain your thinking. • How do you think toxicity is determined? Unit IV • Investigation I-X

  4. The Big Question • How is the toxicity of a substance measured and described? Unit IV • Investigation I-X

  5. You will be able to: • Calculate the toxicity of substances based on the lethal dose. Unit IV • Investigation I-X

  6. Notes • Lethal dose (LD50) is the amount of an ingested substance that kills 50 percent of a test sample. It is expressed in mg/kg, or milligrams of substance per kilogram of body weight. Unit IV • Investigation I-X

  7. Activity • Purpose: In this activity you will compare the toxicity of various substances. Unit IV • Investigation I-X

  8. Making Sense • How is dosage related to toxicity? Unit IV • Investigation I-X

  9. Check-In • Methadone is a medication used as a painkiller and as a treatment for those recovering from heroin addiction. The LD50 for methadone is 95 mg/kg. • Would you consider methadone to be more or less toxic than acetaminophen (LD50 = 2404 mg/kg) or aspirin (LD50 = 200 mg/kg)? • Explain how you would calculate the amount of this substance that would be lethal to a 120-pound human. Unit IV • Investigation I-X

  10. Wrap-Up • Toxicity is relative to dosage: The toxicity (or therapeutic effect) of a substance depends on the dose in which it is received. • The lethal dose (or therapeutic dose) of a substance is often expressed as a ratio between a certain mass of the substance and one kilogram of the body weight of an organism exposed to the substance. Unit IV • Investigation I-X

  11. Toxins Unit – Investigation I Lesson 2: Bearly Alive

  12. ChemCatalyst • Drinking water in our homes contains low concentrations of dissolved chlorine, a highly toxic substance. Why can we drink the water? • What do you think concentration means? Unit IV • Investigation I-X

  13. The Big Question • What are the components of solutions, and how are the concentrations of solutions described? Unit IV • Investigation I-X

  14. You will be able to: • Identify the components of solutions and explain their relationship to the concept of solution concentration. Unit IV • Investigation I-X

  15. Notes • A solution is a mixture of two or more substances that is uniform throughout. The substance in the greatest amount is called the solvent. The solute is dissolved in the solvent. • Concentration is the amount of solute for a specified amount of solvent. A common measure of concentration is moles per L, moles/L, which is referred to as molarity, M. Unit IV • Investigation I-X

  16. Activity • Purpose: This activity introduces you to solution chemistry and allows you to examine solutions of differing concentrations. (cont.) Unit IV • Investigation I-X

  17. Unit IV • Investigation I-X

  18. Making Sense • What do you think is happening in this activity? Write a paragraph explaining your ideas. Include your answers to the following questions: • What causes the size of the gummy bears to change? • Why are the gummy bears in the sugar solutions ranked the way they are? (cont.) Unit IV • Investigation I-X

  19. (cont.) • Why are the gummy bears in the salt solutions different sizes than the gummy bears in the sugar solutions of the same concentration? (cont.) Unit IV • Investigation I-X

  20. (cont.) • The movement of substances from an area of high concentration to an area of lower concentration is called diffusion. Unit IV • Investigation I-X

  21. Check-In • What would happen if you placed a gummy bear in a 1.5 M sugar solution overnight? Use your data table to help you determine the outcome. Draw a picture showing which molecules are moving. Explain your answer in terms of diffusion of water into or out of the bear. Unit IV • Investigation I-X

  22. Wrap-Up • A solution is a mixture that is uniform throughout. The substance in the greatest amount is the solvent. The substance that is dissolved is the solute. • Molarity tells us how many particles or molecules are in solution. Molarity is a measure of the concentration of a solution. (cont.) Unit IV • Investigation I-X

  23. (cont.) • Diffusion is defined as the movement of molecules from an area of higher concentration of that molecule to an area of lower concentration of that molecule. • Salts dissolve in water to give two (or more) ions. Molecular substances do not dissociate; they remain intact as individual molecules. Unit IV • Investigation I-X

  24. Toxins Unit – Investigation I Lesson 3: Mixing It Up!

  25. ChemCatalyst • List three things that dissolve in water. • List three things that do not dissolve in water. Unit IV • Investigation I-X

  26. The Big Question • What is solubility, and how is it determined? Unit IV • Investigation I-X

  27. You will be able to: • Explain the concept of solubility and determine the solubility of a substance. Unit IV • Investigation I-X

  28. Notes • Homogeneous: A mixture in which the substances are distributed uniformly. All solutions are homogeneous by definition. • Heterogeneous: A mixture that is not uniform throughout. Unit IV • Investigation I-X

  29. Activity • Purpose: In this activity you will examine the solubility of five solutes in water. (cont.) Unit IV • Investigation I-X

  30. Unit IV • Investigation I-X

  31. Dye molecules View 1: Uniform distribution of molecules View 2: More molecules at the bottom (cont.) Unit IV • Investigation I-X

  32. Making Sense • Explain how you can tell when a substance is soluble or insoluble in water. Unit IV • Investigation I-X

  33. Notes • A solute is a gas, liquid, or solid that dissolves when mixed with another substance. • A solvent is the substance present in the greatest quantity in a solution. Solvents are usually liquids. (cont.) Unit IV • Investigation I-X

  34. (cont.) • Soluble substances are solutes that dissolve completely. • Insoluble substances are those that do not dissolve at all. • Partially soluble substances are those for which only a certain amount will dissolve. Many substances are partially soluble. Unit IV • Investigation I-X

  35. Check-In • There is solid sugar at the bottom of your tea. Why do the last sips taste sweeter? • All of the sugar in your tea is dissolved. The last sips taste the same as the first. Use a molecular view of sugar dissolved in water to explain why. Unit IV • Investigation I-X

  36. Wrap-Up • Gases, liquids, and solids can dissolve in water. However, some substances are not soluble. • Partially soluble means that when two substances are mixed, a solution forms but one substance is leftover. • Solutions are homogeneous. The molecules or ions of the solute are distributed uniformly between the solvent molecules. Unit IV • Investigation I-X

  37. Toxins Unit – Investigation I Lesson 4: Weighing In

  38. ChemCatalyst • Which do you think is more toxic—one mole of arsenic, As, or ten grams of arsenic? Explain your reasoning. Unit IV • Investigation I-X

  39. The Big Question • How is the mole concept used to connect the mass of a sample to the number of particles it contains? Unit IV • Investigation I-X

  40. You will be able to: • Use the molar mass of a substance to find the number of molecules in a sample. Unit IV • Investigation I-X

  41. Activity • Purpose: The purpose of today's lesson is to explore the relationship between mass and moles. (cont.) Unit IV • Investigation I-X

  42. (cont.) (cont.) Unit IV • Investigation I-X

  43. (cont.) Unit IV • Investigation I-X

  44. Making Sense • How is measuring the mass of a substance the same as counting? Unit IV • Investigation I-X

  45. Notes • The molar mass of a substance is how much one mole of that substance weighs. Molar mass is the sum of all of the atomic masses (in grams) in a chemical formula. (cont.) Unit IV • Investigation I-X

  46. molar mass in grams/mole add the atomic weights of the atoms in the chemical formula moles 6.02  1023 (Avogadro’s number) of each of the atoms in the chemical formula mass in grams weight of the substance (cont.) Unit IV • Investigation I-X

  47. Check-In • You have one mole of NaCl and one mole of KCl. Which one weighs more? Explain your thinking. Unit IV • Investigation I-X

  48. Wrap-Up • The atomic weight on the periodic table is equivalent to the mass of 1 mole of atoms of the element in grams. • The molar mass of a compound is the sum of the atomic weights of the atoms in the compound. • Molar mass allows you to convert between moles and grams. Unit IV • Investigation I-X

  49. Toxins Unit – Investigation I Lesson 5: Finding Solutions

  50. ChemCatalyst • Consider the following solutions: • 1.0 L • 1.0 M C6H12O6 • (glucose) • 1.0 L • 1.0 M C12H22O11 • (sucrose) • 500 mL • 1.0 M C12H22O11 • (sucrose) (cont.) Unit IV • Investigation I-X