CHEMISTRY 11 TEACHER’S CHAPTER 4 NOTES
CHEMISTRY 11
FOR THE TEACHER
Lesson Objectives
• Review, reinforce, and extend the concepts in Chapter 4: The Effects of
Chemical Reactions.
• This lesson relates to expectations C1.1, C1.2, C2.1, C2.2, C2.4, C2.5,
C2.6, and C3.1.
Lesson Notes
Slide 5 and 6
• These slides walk students through the procedure for balancing a chemical equation. NB: the second slide is a “giveaway” for the first slide, so allow enough time to complete the first slide before progressing.
• The discussion suggestion is an opportunity for students to think about why chemical equations must balance.
FOR THE TEACHER
Lesson Notes
Slide 8
• This matching exercise picks up the theme of relating specific chemical reaction types to real-world phenomena.
• Ocean acidification in particular is a topic that could be further explored, perhaps together with the mercury topic from Section 4.5, with the overall theme of the threat to ocean food chains.
Slide 9
• These questions could be used as the basis for developing an “executive summary” of Section 4.3, which could in turn be the jump-off point for further research.
FOR THE TEACHER
Lesson Notes
Slide 14
• The statements, once completed, tell the “story” uncovered by the researchers. The discussion is intended to draw out the understanding that this is still not the whole story. One conclusion that may emerge is that interconnections in the ecosphere create complexity, and make predicting the effects of human activity extremely challenging.
Section 4.1
Write the balanced chemical equation for the reaction of sodium with lead (II) sulfate to produce sodium sulfate and lead.
Step 1: Put the chemical symbols at the bottom of this slide into the correct positions to form a skeleton equation.
+ +
2
Step 2: Count the atom(s) and polyatomic ions on each side of the equation. Record your results.
Reactants
Na atom(s)
Products
Na atom(s)
Pb
SO
4 atom(s) ion(s)
Pb atom(s)
SO
4 ion(s)
Is your equation balanced?
Section 4.1
Write the balanced chemical equation for the reaction of sodium with lead (II) sulfate to produce sodium sulfate and lead.
Step 3: Multiply the formulas by the appropriate coefficients to balance the equation. Determine the coefficients.
Pb Na + PbSO
4
Na
2
SO
4
+
Reactants
Na atom(s)
Products
Na atom(s)
Pb atom(s)
SO
4
ion(s)
Pb atom(s)
SO
4
ion(s)
Step 4: Write the final balanced chemical equation.
+ +
Discussion: Balancing a Chemical Equation
Section 4.1
What is the connection between balancing a chemical equation and conservation of mass?
Synthesis and Decomposition Reactions
Look at the following reactions. Identify the reaction type and the reactant and/or product. Complete the table by putting labels in the appropriate places.
Decomposition
Synthesis
H
2
CO
3
(product) O
2
(product)
CO
2
(reactant) Mg (reactant)
Reaction Type Reactant and/or Product
Respiratory products acidify oceans.
A compound here produces a gas that speeds up burning.
Burning metal creates these sparkles.
Section 4.3
Garbage Gasification
Gasification is a response to the challenge of the huge quantities of waste produced by industrial societies, but it is controversial. Click the screen to reveal the questions on this chemical technology and answer them.
1
What type of reaction is
1
2
What substances principally make up syngas?
3
4
What are the possible uses of syngas?
What are two key objections to gasification?
Section 4.4
Circle the ion that may be displaced and place a square around the element that may do the displacing in each of the following reactions. Use the activity series to determine if the reaction will occur. If it does occur, write the balanced equation for the reaction. If it does not occur, write NR.
Mg(s) +
CI
2
(aq) +
FeCI
2
(aq)
KBr(aq)
Cu(s) +
Na(s) +
Pb(NO
3
)
2
(aq)
H
2
SO
4
(aq)
More: Single Displacement Reactions
Section 4.4
Click the following image to watch an animation about single displacement reaction.
Single Displacement Reaction: In this single displacement reaction, element A displaces element B to form a new compound AC and a new element B.
Section 4.5
Mercury and ozone, two pollutants that accumulate in the Arctic atmosphere, both mysteriously vanish each spring. Complete the following statements about recent findings by Environment Canada researchers using the following words. bromine oxygen microorganisms bromide mercury
1. Seawater contains dissolved bromide _______________ ions. Spring sunlight converts these to highly reactive _______________ atoms.
2. The _______________ reacts with _______________ from the ozone to form _______________ monoxide.
3. Both the elemental _______________ and the _______________ monixide then react with the _______________ in the atmosphere. The resulting _______________(II) ions then “snow out.”
4. Later, the _______________(II) ions are reconverted to elemental mercury that can be absorbed by _______________ and then travel up the food chain.
Discussion: Missing Mercury
Section 4.5
Is the mystery of the missing mercury now completely solved?
Section 4.6
Double Displacement Reactions
Use the solubility table to predict if a precipitate will form. Write the balanced equation for the reaction and identify the precipitate formed. If there is no reaction, write NR.
AgNO
3
(aq) + BaCI
2
(aq)
CuSO
4
(aq) + Na
2
S(aq)
FeSO
4
(aq) +
ZnCI
2
(aq) +
MgCO
3
(s) +
KBr(aq)
Na
2
SO
4
(aq)
KOH(aq)
More: Double Displacement Reactions
Section 4.6
Click the following image to watch an animation about double displacement reaction.
Double Displacement Reaction: In this double displacement reaction, element A and element C trade places to form two new compounds.
One or both of these new compounds may be a precipitate or a gas.
Activity Series
Section 4.4
Halogen Activity Series most reactive
Section 4.4
least reactive
Solubility Table
Solubility very soluble (aq)
≥0.1 mol/L
Ion
_
NO
3
CI and other halides
SO
4
2−
C
2
H
3
O
2
−
Na + and K +
NH
4
+
CO
3
2−
Slightly soluble (s)
<0.1 mol/L
PO
4
3−
OH -
S
2−
Section 4.6
Exceptions none except with Cu + , Ag + , Hg
2
2+ , Pb 2+ except with Ca 2+ , Ba 2+ , Sr 2+ , Hg 2+ , Pb 2+ , Ag +
Ag + none none except with Group 1 ions and NH
4
+ except with Group 1 ions and NH
4
+ except with Group 1 ions, Ca 2+ , Ba 2+ , Sr 2+ except with Group 1 and 2 ions and NH
4
+
ANSWERS
Section 4.1
Write the balanced chemical equation for the reaction of sodium with lead (II) sulfate to produce sodium sulfate and lead.
Step 1: Put the chemical symbols at the bottom of this slide into the correct positions to form a skeleton equation.
Na + Pb SO
4
Na SO
4
+ Pb
2
Step 2: Count the atom(s) and polyatomic ions on each side of the equation. Record your results.
Reactants
1 Na atom(s)
Products
2 Na atom(s)
1
1
Pb
SO
4 atom(s) ion(s)
1
1
Pb
SO
4 atom(s) ion(s)
Is your equation balanced?
No
Section 4.1
Write the balanced chemical equation for the reaction of sodium with lead (II) sulfate to produce sodium sulfate and lead.
Step 3: Multiply the formulas by the appropriate coefficients to balance the equation. Determine the coefficients.
2
Na +
1
PbSO
4
1
Na
2
SO
4
+
1
Pb
Reactants
2 Na atom(s)
Products
2 Na atom(s)
1
1
Pb atom(s)
SO
4
ion(s)
1
1
Pb atom(s)
SO
4
ion(s)
Step 4: Write the final balanced chemical equation.
2Na + PbSO
4
Na
2
SO
4
+ Pb
Synthesis and Decomposition Reactions
Look at the following reactions. Identify the reaction type and the reactant and/or product. Complete the table by putting labels in the appropriate places.
Decomposition
Synthesis
H
2
CO
3
(product) O
2
(product)
CO
2
(reactant) Mg (reactant)
Reaction Type Reactant and/or Product
Respiratory products acidify oceans.
A compound here produces a gas that speeds up burning.
Burning metal creates these sparkles.
Synthesis
Decomposition
Synthesis
CO
2
(reactant)
H
2
CO
3
(product)
O
2
(product)
Mg (reactant)
Section 4.3
Garbage Gasification
Sample answers:
1. A decomposition reaction, in which large carbon-based molecules are broken down into the mixture of (mostly) hydrogen and carbon monoxide.
2. Syngas is mostly hydrogen and carbon monoxide.
3. The possible uses of syngas include generating electricity and making other carbon-based chemicals. (The slag formed when syngas is produced can be used for road surfacing.)
4. Gasification may create toxic emissions; and it may discourage people from recycling.
Section 4.4
Circle the ion that may be displaced and place a square around the element that may do the displacing in each of the following reactions. Use the activity series to determine if the reaction will occur. If it does occur, write the balanced equation for the reaction. If it does not occur, write NR.
2
Mg(s) + FeCI
2
(aq)
CI
2
(aq) +
2
KBr(aq)
Cu(s) +
Na(s) +
MgCI
2
(aq) + Fe(s)
2KCI(aq) + Br
2
(aq)
Pb(NO
3
)
2
(aq)
H
2
SO
4
(aq)
NR
Na
2
SO
4
(aq) + H
2
(g)
Section 4.5
Mercury and ozone, two pollutants that accumulate in the Arctic atmosphere, both mysteriously vanish each spring. Complete the following statements about recent findings by Environment Canada researchers using the following words. bromine oxygen microorganisms bromide mercury sunlight converts these to highly reactive _______________ atoms. bromine from the ozone to form _______________ monoxide.
3. Both the elemental _______________ bromine monixide then react with the _______________ in the atmosphere. The mercury that can be absorbed by _______________ and then travel up the food chain.
Section 4.6
Double Displacement Reactions
Use the solubility table to predict if a precipitate will form. Write the balanced equation for the reaction and identify the precipitate formed. If there is no reaction, write NR.
2
AgNO
3
(aq) + BaCI
2
(aq) 2AgCI(s) + Ba(NO
3
)
2
(aq)
CuSO
4
(aq) + Na
2
S(aq) Na
2
SO
4
(aq) + CuS(s)
FeSO
4
(aq) + KBr(aq)
NR
ZnCI
2
(aq) + Na
2
SO
4
(aq)
MgCO
3
(s) +
2
KOH(aq)
NR
K
2
CO
3
(aq) + Mg(OH)
2
(s)
Answers for Discussion Questions:
Slide 7
Sample answer:
Conservation of mass for chemical equations means conservation of atoms. The key to balancing an equation is to make sure that there are equal numbers of each type of atom on both sides of the equation.
Answers for Discussion Questions:
Slide 13
Sample answer:
No, because some of the missing mercury is still unaccounted for. One possibility is that CFCs, which remain in the atmosphere for many years, may be involved, or there may be other processes that scientists have not yet discovered.
Credits
Slides 8 and 22: top John A. Anderson/Shutterstock; bottom Charles D.
Winters Photo Researchers, Inc.
Slide 14 and 25: Spencer Brown
