Toxins Unit

1
Toxins Unit

• Investigation III Precipitating Toxins

Lesson 1 Solid Evidence
Lesson 2 Ive 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?

4
The Big Question

• What is a precipitation reaction and how can you
  determine whether a precipitate will form?

5
You will be able to

• Use a solubility table to predict whether a
  particular chemical reaction will be a
  precipitation reaction.

6
Notes

• CaCl2 (aq) Na2C2O4 (aq) ?
• 2 NaCl (aq) CaC2O4 (s)

(cont.)
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.)
8
S very soluble, N not very soluble
9
Activity

• Purpose In this experiment, you will predict the
  solubility of various ionic solids and then test
  your predictions.

10
Making Sense

• Write three solubility rules. (Example Alkali
  metal salts tend to be soluble.)

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.)
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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.)
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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.

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.

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.

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Toxins Unit Investigation III

• Lesson 2
• Ive 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.

18
The Big Question

• What is the role of ions in the precipitation
  reaction process?

19
You will be able to

• Predict the products of precipitation reactions
  and write balanced chemical equations that
  represent the precipitation reaction process.

20
Activity

• Purpose This activity provides practice with
  equations involving ionic compounds.

(cont.)
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(cont.)
(cont.)
22
(cont.)
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?

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.)
25
Notes (cont.)

• The correct phase of the reactants and products
  must be indicated. (Check solubility rules or
  tables.)

(cont.)
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Notes (cont.)

• Polyatomic ion An ion consisting of several
  non-metal atoms covalently bonded to one another.

(cont.)
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Notes (cont.)

• NaCl (aq) AgNO3 (aq) ?
• AgCl (s) NaNO3 (aq)

(cont.)
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Notes (cont.)

• Na(aq) Cl(aq) Ag(aq) NO3(aq) ?
• AgCl(s) Na(aq) NO3(aq)

(cont.)
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Notes (cont.)

• Na(aq) Cl(aq) Ag(aq) NO3(aq) ?
• AgCl(s) Na(aq) NO3(aq)

(cont.)
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Notes (cont.)

• Ag(aq) Cl(aq) ? AgCl(s)

(cont.)
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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.

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).

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.

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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.)
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.

37
The Big Question

• What do the coefficients in a balanced chemical
  reaction mean, and how do they relate to
  real-world observations?

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.

39
Activity

• Purpose You will determine what ratio of
  reactants gives the maximum amount of products.

(cont.)
40
(cont.)
Calcium oxalate kidney stones
(cont.)
41
(cont.)
Calcium phosphate bones
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.

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.

44
Check-In

• The reaction to form silver phosphate, Ag3PO4 (s)
  is given below
• AgNO3 (aq) Na3PO4 (aq) ?
• Ag3PO4 (s) NaNO3 (aq)

(cont.)
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

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.

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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.)
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?

50
The Big Question

• How does the mole concept help you predict the
  amount of each product in a particular reaction?

51
You will be able to

• Calculate the quantity of a product formed in a
  reaction from a given quantity of starting
  reactants.

52
Activity

• Purpose You will relate grams of reactants and
  grams of products using moles as an intermediary.

(cont.)
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(cont.)
(cont.)
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(cont.)
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Making Sense

• Explain how you determined the number of grams of
  white-purple pieces you needed to make
  approximately 36 grams of white-blue pieces.
  Explain how you determined the number of grams of
  Na2C2O4 you need to make 12.8 g of CaC2O4.

56
Check-In

• Mercury was extracted from mercury sulfide for
  use in gold mining by the reaction given below
• HgS (s) ? Hg (l) S (s)
• What would you observe?
• If you have 0.5 moles of HgS, how many moles of
  Hg can you make?
• How many grams of HgS do you need to produce 2
  moles of Hg?

57
Wrap-Up

• In order to make a specified mass of product,
  chemists must determine how many moles of that
  product they are trying to create.
• In completing calculations for chemical
  reactions, chemists convert back and forth
  between grams and moles.

58
Toxins Unit Investigation III

• Lesson 5
• Mass Appeal

59
ChemCatalyst

• The reaction given below produces the main
  substance found in human bones (calcium
  phosphate)
• 3 CaCl2 (aq) 2 Na3PO4 (aq) ?
• calcium chloride sodium phosphate
• Ca3(PO4)2 (s) 6 NaCl (aq)
• calcium phosphate sodium chloride

(cont.)
60
(cont.)

• If you react 6 moles of calcium chloride, CaCl2,
  how many moles of calcium phosphate can you make?
• If you react 111 grams of CaCl2, how many moles
  of calcium phosphate can you make?

61
The Big Question

• How can the mole concept be used to calculate the
  actual mass of products produced, or the mass of
  reactants needed, in a chemical reaction?

62
You will be able to

• Use the mole concept and balanced chemical
  equations to convert back and forth between
  masses of reactants.

63
Notes

• Stoichiometry Problems involving conversions
  between masses and moles of reactants and
  products.
• Mole ratio The proportions in which two
  substances combine or form.
• N2 3 H2 ? 2 NH3

64
Activity

• Purpose In this activity you will perform
  stoichiometric calculations.

(cont.)
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(cont.)
(cont.)
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(cont.)
(cont.)
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(cont.)
(cont.)
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(cont.)
69
Making Sense

• Outline the steps you took to calculate the
  number of grams of calcium chloride needed to
  make 50 grams of calcium phosphate.

70
Notes
(cont.)
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(cont.)

• Example
• How many grams of calcium phosphate can be made
  with 25 grams of calcium chloride?

72
Check-In

• Consider the following reaction
• Mg (s) 2 HCl (aq) ? MgCl2 (aq) H2( g)
• What would you observe?
• How many grams of magnesium, Mg, do you need to
  produce 190 g, or 2 moles, of magnesium chloride,
  MgCl2?

73
Wrap-Up

• Stoichiometric calculations are those involving
  masses of reactants and products in chemical
  reactions.
• In order to calculate the mass of reactant needed
  to make a certain mass of product it is necessary
  to convert mass to moles and then back again to
  mass.
• Mole ratios assist in converting back and forth
  between moles of reactant and product.

74
Toxins Unit Investigation III

• Lesson 6
• Get the Lead Out

75
ChemCatalyst

• Heavy metals such as thallium dissolved in the
  water supply can be very toxic. Thallium can be
  removed from water by precipitation as thallium
  chloride.
• TlNO3 (aq) NaCl (aq) ?
• TlCl (s) NaNO3 (aq)

(cont.)
76
(cont.)

• Which will produce more moles of TlCl?
• 10 g TlNO3 and 10 g NaCl
• 12 g TlNO3 and 8 g NaCl
• 8 g TlNO3 and 12 g NaCl

77
The Big Question

• What happens in a chemical reaction when one of
  the reactants runs out before the other?

78
You will be able to

• Explain the concept of a limiting reactant and
  how it affects the amount of a product produced
  in a chemical reaction.

79
Notes

• In a stoichiometric mixture the reactants are
  mixed in the mole ratios specified by the
  balanced equation.
• A limiting reactant is a reactant that gets used
  up because the mixture is not stoichiometric.

80
Activity

• Purpose In this activity, you will consider how
  to determine if one reactant is in excess.

81
Making Sense

• If you have 662 g Pb(NO3)2 dissolved in a water
  supply and you add 230 g NaCl, how can you
  determine if you have enough NaCl to remove the
  lead as solid PbCl2?

82
Notes (cont.)

• 3AB 2CD ? AD 6 CB

83
(cont.)

• Sample problem
• We take vitamins and mineral supplements so that
  they do not become limiting reactants in our
  body. If you have 13.3 g CaCl2 and 9.84 g Na3PO4
  available, how many grams of Ca3(PO4)2 (bone) can
  you make? Should you take a calcium supplement?
  Explain your thinking.

84
Check-In

• Consider the following reaction
• N2 (g) 3 H2 (g) ? 2 NH3 (g)
• If you have 28.0 g N2 and 12.0 g H2, which
  reactant is the limiting reactant? Show your work.

85
Wrap-Up

• The limiting reactant is the substance that gets
  used up in a chemical reaction.
• To determine the limiting reactant, calculate how
  many moles of product you will make for each mole
  of reactant. The one that gives fewer moles is
  the limiting reactant.

86
Toxins Unit Investigation III

• Lesson 7
• Grammies

87
ChemCatalyst

• These two cards represent two soluble salts that
  you are combining. Assume you have only one mole
  of each substance in solution.

(cont.)
88
(cont.)

• Write a balanced equation for this precipitation
  reaction.
• What precipitate will form?
• What is the maximum number of moles of
  precipitate that will form when you mix 1 mole of
  the reactants?
• How many grams of precipitate will form?

89
The Big Question

• How can the limiting reactant concept be used to
  predict quantity of product from a specific
  chemical reaction?

90
You will be able to

• Use the limiting reactant concept and a balanced
  chemical equation to calculate the quantity of a
  product that can be produced by a particular
  chemical reaction.

91
Activity

• Purpose This card game will allow you to
  practice all youve learned about precipitation
  reactions and solubility trends.

(cont.)
92
S very soluble, N not very soluble
93
(No Transcript)
94
Making Sense

• No Making Sense question

95
Check-In

• No Check-In exercise.

96
Wrap-Up

• No wrap-up points.