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1. Toxins Unit Investigation I: Dissolving Toxins
2. Toxins Unit Investigation I Lesson 1:
Lethal Dose
3. Unit IV Investigation I-X 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?
4. Unit IV Investigation I-X The Big Question How is the toxicity of a substance measured and described?
5. Unit IV Investigation I-X You will be able to: Calculate the toxicity of substances based on the lethal dose.
6. Unit IV Investigation I-X 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.
7. Unit IV Investigation I-X Activity Purpose: In this activity you will compare the toxicity of various substances.
8. Unit IV Investigation I-X Making Sense How is dosage related to toxicity?
9. Unit IV Investigation I-X 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.
10. Unit IV Investigation I-X 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.
11. Toxins Unit Investigation I Lesson 2:
Bearly Alive
12. Unit IV Investigation I-X 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?
13. Unit IV Investigation I-X The Big Question What are the components of solutions, and how are the concentrations of solutions described?
14. Unit IV Investigation I-X You will be able to: Identify the components of solutions and explain their relationship to the concept of solution concentration.
15. Unit IV Investigation I-X 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.
16. Unit IV Investigation I-X Activity Purpose: This activity introduces you to solution chemistry and allows you to examine solutions of differing concentrations.
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18. Unit IV Investigation I-X 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?
19. Unit IV Investigation I-X Why are the gummy bears in the salt solutions different sizes than the gummy bears in the sugar solutions of the same concentration?
20. Unit IV Investigation I-X The movement of substances from an area of high concentration to an area of lower concentration is called diffusion.
21. Unit IV Investigation I-X 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.
22. Unit IV Investigation I-X 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.
23. Unit IV Investigation I-X 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.
24. Toxins Unit Investigation I Lesson 3:
Mixing It Up!
25. Unit IV Investigation I-X ChemCatalyst List three things that dissolve in water.
List three things that do not dissolve in water.
26. Unit IV Investigation I-X The Big Question What is solubility, and how is it determined?
27. Unit IV Investigation I-X You will be able to: Explain the concept of solubility and determine the solubility of a substance.
28. Unit IV Investigation I-X Homogeneous: A mixture in which the substances are distributed uniformly. All solutions are homogeneous by definition.
Heterogeneous: A mixture that is not uniform throughout.
29. Unit IV Investigation I-X Activity Purpose: In this activity you will examine the solubility of five solutes in water.
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32. Unit IV Investigation I-X Making Sense Explain how you can tell when a substance is soluble or insoluble in water.
33. Unit IV Investigation I-X 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.
34. Unit IV Investigation I-X 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.
35. Unit IV Investigation I-X 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.
36. Unit IV Investigation I-X 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.
37. Toxins Unit Investigation I Lesson 4:
Weighing In
38. Unit IV Investigation I-X ChemCatalyst Which do you think is more toxicone mole of arsenic, As, or ten grams of arsenic? Explain your reasoning.
39. Unit IV Investigation I-X The Big Question How is the mole concept used to connect the mass of a sample to the number of particles it contains?
40. Unit IV Investigation I-X You will be able to: Use the molar mass of a substance to find the number of molecules in a sample.
41. Unit IV Investigation I-X Activity Purpose: The purpose of today's lesson is to explore the relationship between mass and moles.
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44. Unit IV Investigation I-X Making Sense How is measuring the mass of a substance the same as counting?
45. Unit IV Investigation I-X 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.
46. Unit IV Investigation I-X
47. Unit IV Investigation I-X Check-In You have one mole of NaCl and one mole of KCl. Which one weighs more? Explain your thinking.
48. Unit IV Investigation I-X 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.
49. Toxins Unit Investigation I Lesson 5:
Finding Solutions
50. Unit IV Investigation I-X ChemCatalyst Consider the following solutions:
51. Unit IV Investigation I-X Which solution has the most molecules? Explain.
Which solution has the greatest concentration? Explain.
Which solution weighs the most? Explain.
52. Unit IV Investigation I-X The Big Question What are the methods that can be used to produce a solution of a specific concentration?
53. Unit IV Investigation I-X You will be able to: Produce a solution of specific concentration by using the mass of solute and its molar mass or by using dilution.
54. Unit IV Investigation I-X Activity Purpose: You will prepare four solutions by two different methods.
Volume conversion: 1 L = 1000 mL
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58. Unit IV Investigation I-X Making Sense Describe two ways to make a 0.010 M sugar solution.
59. Unit IV Investigation I-X Check-In How many moles of sucrose does 100 mL of a 0.10 M sucrose solution contain?
How many moles of sucrose does 25 mL of a 0.10 M sucrose solution contain?
60. Unit IV Investigation I-X Wrap-Up When concentration is expressed in moles of solute per liter of solution it is referred to as molarity.
Solutions of specific concentrations can be created by weighing out the solute or by dilution of an existing solution of known concentration.
61. Toxins Unit Investigation I Lesson 6:
Holey Moley
62. Unit IV Investigation I-X ChemCatalyst How would you calculate the total amount of glucose, in grams, in the blood of an average human?
Useful information:
Blood volume = 5.5 L
Glucose concentration = 0.0056 M
Molar mass of glucose (C6H12O6) = 180 g/mol
63. Unit IV Investigation I-X The Big Question What is the connection between the mass of a solute, its molar mass, and the concentration of solution it is in?
64. Unit IV Investigation I-X You will be able to: Convert between the mass of solute in solution, its concentration, and its molar mass.
65. Unit IV Investigation I-X Proportional analysis
Step 1: Convert liters to moles using the concentration.
x = 0.031 moles glucose
66. Unit IV Investigation I-X Step 2: Convert moles to grams using the molar mass
y = 5.5 g glucose
67. Unit IV Investigation I-X Dimensional analysis
68. Unit IV Investigation I-X Activity Purpose: You will practice solving problems in which you convert between mass of solute, moles of solute, and liters of solution using molecular weight and molarity.
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72. Unit IV Investigation I-X Making Sense Explain how to make a glucose solution that has the same concentration as blood.
Explain how to dilute a 1.0 M glucose solution so that it has the same concentration as human blood.
73. Unit IV Investigation I-X Sample Problem #1 Calculating molarity of a solution:
What is the molarity of 5.5 L of blood containing 10 grams of glucose?
74. Unit IV Investigation I-X Sample Problem #2 Calculating grams of solute needed for a specific molarity.
How many grams of glucose, C6H12O6, would you need to create 250 mL of solution with a molarity of 0.0050 moles / liter?
75. Unit IV Investigation I-X When a solution is diluted, solvent is added without the addition of more solute. Since the amount of solute is not changed, our calculations reflect this fact.
# of moles before dilution =
# of moles after dilution
Since the moles of solute is equal to the molarity multiplied by the volume, we can substitute these values into the equation.
M1V1 = M2V2
76. Unit IV Investigation I-X Sample Problem #1 Calculate the volume of a known solution needed to dilute to a new molarity.
What volume of 0.75 M glucose is needed to make 1 liter of 0.15 M glucose?
77. Unit IV Investigation I-X Check-In How many grams of glucose would you need to make 100 mL of 1.0 M solution? The molecular formula of glucose is C6H12O6.
78. Unit IV Investigation I-X Wrap-Up Mass of solute, moles of solute, and volume of solution are related to one another by the molecular weight of the solute and the concentration of the solution.
If you have a certain volume of a solution of a specified concentration, then you know how many moles of solute you have.
79. Toxins Unit Investigation I Lesson 7:
Is It Toxic?
80. Unit IV Investigation I-X ChemCatalyst Suppose you wanted to determine if your tap water contained lead sulfate, PbSO4 (which is toxic).
Do you expect the weight of 100 ml of pure water to be the same as that of a 100 ml solution containing PbSO4? Explain your reasoning.
81. Unit IV Investigation I-X The Big Question
82. Unit IV Investigation I-X You will be able to: Deduce some differences among solutions that look identical.
83. Unit IV Investigation I-X Activity Purpose: You will determine the identities of solutions given to you by your instructor, and decide which is safe to drink.
84. Unit IV Investigation I-X Safety note: Do not get NaOH on your skin. In case of a spill, rinse with large amounts of water. Wear goggles.
85. Unit IV Investigation I-X Making Sense Examine the toxicities given below. Which solution would be most harmful if you drank it? Which would be least harmful to drink? Explain your thinking.
86. Unit IV Investigation I-X
87. Unit IV Investigation I-X Check-In Place the following 1.0 M solutions in order of increasing mass, from the smallest mass to the largest mass: NaCl, KCl, and CaCl2.
88. Unit IV Investigation I-X Wrap-Up Solutions have different masses depending on the molar mass of the solute.
Pure water weighs exactly 1.0 g per 1.0 mL. If 1.0 mL weighs more or less than this, then the water is not pure.