UKanTeach Lesson Plan Format
Balancing Oxidation Reduction Reactions
Author(s): Trinda Wheeler
Team Members: Trinda Wheeler
Date lesson will be taught: November 16-17
Grade level: 10-11
Lesson Source: Holt Chemistry
Concepts:
Oxidation/Reduction,
Oxidation Numbers,
Balancing Redox Reactions
Reducing and Oxidizing Agents
Objectives:
Identify atoms that are oxidized or reduced through electron transfer,
Assign oxidation numbers to atoms in compounds and ions,
Identify redox reactions by analyzing changes in oxidation numbers for different
atoms in the reaction,
Balance equations for oxidation-reduction reactions through the half-reaction
method.
Kansas Science Standards, Benchmarks, and Indicators:
STANDARD 2A: CHEMISTRY
Benchmark 3: The student will gain a basic concept of chemical reactions.
1. ▲ understands a chemical reaction occurs when one or more substances
(reactants) react to form a different chemical substance(s) (products). There are
different types of chemical reactions all of which demonstrate the Law of
Conservation of Matter and Energy.
a. Chemical reactions are written as balanced chemical equations. In ordinary
chemical reactions, the number and kind of atoms must be conserved.
b. Examples of chemical reactions are synthesis, decomposition, combustion,
single and double replacement, acid/base, and oxidation/reduction.
Materials list:Apple slices
Rusted iron
Candle
Matches
ELMO Projector
Notecards
Advance preparation:
Day1: Cut apple slices at least 20 minutes prior to class
Prepare and copy handouts
Prepare PowerPoint with definitions and oxidation rules
Day 2: Prepare and copy handouts
Prepare PowerPoint with video and balancing rules
Handouts:
Day1: Assigning Oxidation Numbers Toolkit
Students will take notes during the lesson.
Day 2: General Plan for Balancing Redox Equations
Students will take notes during the lesson.
Accommodations: There are no students with IEP’s in this class. Students will work in pairs
and groups, where peer support can accommodate learning styles. The teacher will
circulate among the groups to check for understanding and provide assistance when
needed.
Safety: No chemicals will be used in this lesson. Instead, videos will be shown for “virtual”
demonstrations.
Five-E Plan
Day 1 – 50 minutes
Teacher Does
Engage:
Learning Experience(s)
Time: ___5___minutes
Display browned apple
slices, a rusted piece of
iron, and a burning candle.
Explain that these reaction
are oxidation reactions.
Many, though not all
oxidation reactions involve
oxygen.
Probing Questions
Critical questions that will
connect to prior knowledge
and create a need to know.
Student responses
Expected Student
Responses/Misconceptions
What evidence do you see
that chemical reactions
have and/or are taking
place here?
The apple turned brown.
The iron rusted.
The candle emits light, heat,
and smoke.
What could have been done
to stop these reactions?
Don’t cut up the apple, or
seal it up after cutting.
Paint the iron.
Blow out the candle.
What is a common reactant
in the three reactions?
Oxygen
Teacher Does
Explore:
Learning Experience(s)
Time: __25____minutes
Review polar and ionic
bonds.
Define oxidation,
reduction, and redox
reactions. Show definitions
and simple example
reaction equations on PPT.
Probing Questions
Critical questions that will
guide students to a common
set of experiences.
Student responses
Expected Student
Responses/Misconceptions
What happens to the
electrons involved in ionic
bonds? Polar covalent?
Ionic-electrons are
transferred resulting in
ions. Polar-electron is
unequally shared, more
likely to be near one atom.
Since Na loses an electron
when forming NaCl, is it
reduced or oxidized? What
happens to Cl?
Na - Oxidized.
Cl - Reduced
Teach mnemonic devices to What do you think OIL RIG
keep oxidation and
might stand for?
reduction straight (on PPT).
How about LEO the lion
says GER?
Oxidation Is Losing
electrons, Reduction Is
Gaining electrons.
Losing Electrons is
Oxidation, Gaining
Electrons is Reduction.
Explain oxidation numbers
and their necessity in
balancing redox equations.
If an atom’s oxidation
number decreases in the
reaction, is it reduced or
oxidized?
Reduced. (This will likely
require some explanation
relating to the definition of
oxidation numbers)
Misconception: Oxidation
number are the same as
charge – they are not!
Handout oxidation numbers
toolkit and go through each
rule. As a class, assign ox.
#’s for S2O72-.
Which rule applies/help us?
g. Ox# of O is -2
How do find the ox# of S?
Solve for x: 2x+(-14)=-2
In pairs, have students
assign ox# to each atom in
an assigned molecule.
Molecules/ions: NH4+, Al,
H2O, Pb2+, H2, PbSO4,
KClO3, BF3, Ca(OH)2,
Fe2(CO3)3, H2PO4-,
NH4NO3, KOH, NO3-,
NaClO4
Which rule(s) apply?
What should be on the right
side of equation to solve for
the unknown ox #?
Various answers.
Teacher Does
Explain:
Learning Experience(s)
Time: __10____minutes
Have each group label their
assigned molecule with
oxidation numbers (all will
be written on the board).
Probing Questions
Critical questions that will
help students clarify their
understanding and
introduce information
related to the lesson
concepts/skills.
Student responses
Expected Student
Responses/Misconceptions
Which rule(s) did you use?
Various answers.
What equation did you use
to solve for unknowns?
Does anyone disagree with
their answer? Why?
Teacher Does
Extend / Elaborate:
Learning Experience(s)
Time: __5____minutes
Show video demonstrating
three oxidation states of
Mn.
Note that glazes on pottery
contain transition metals
which changes color after
firing in the kiln in the
presence of oxygen.
Probing Questions
Critical questions that will
help students extend or
apply their newly acquired
concepts/skills in new
situations.
Student responses
Expected Student
Responses/Misconceptions
I’m using KMnO4. What is
the oxidation number of
Mn?
+7
Mn is reduced in the
presence of NaOH and
sugar. What do you think
the changing colors were
showing us?
Different oxidation states
for Mn. (They are +7, +6,
and +4)
What type of element has
different oxidation states?
Transition metals.
Teacher Does
Evaluate:
Include summative
evaluation below.
Time: __5____minutes
Probing Questions
Critical questions that ask
students to demonstrate
their understanding of the
concepts and process skills.
These questions must
directly relate to the
lesson’s performance
objectives.
Student responses
Expected Student
Outcomes
Quiz (This is not for a grade, it is to let me know if we are ready to move tomorrow. You may
use your notes and your toolkit.):
What happens to the electrons of an atom when it is oxidized?
Electrons are lost.
What happens to the oxidation number of an atom when it is reduced?
The oxidation number decreases.
During a reaction, KMnO4 is changed to K2MnO4. Find the oxidation number of Mn in each
compound and determine if manganese was oxidized or reduced.
Mn in KMnO4 = +7, Mn in K2MnO4 = +6. Mn was reduced.
Day 2 – 50 minutes
Teacher Does
Probing Questions
Critical questions that will
connect to prior knowledge
and create a need to know.
Student responses
Expected Student
Responses/Misconceptions
What were our mnemonic
devices?
OIL RIG
LEO the lion says GER
Is oxidation number the
same as charge?
Sometimes, but not always.
Show video of airbag
deploying when granny hits
the bumper with her purse.
How does an airbag work?
A reaction causes a release
of gas.
Show 2-step reaction.
How can we tell if this is a
redox reaction?
Assign oxidation numbers to
the reactants and products.
Engage:
Learning Experience(s)
Time: ___5___minutes
Give students teacher’s
general impression of the
quizzes papers from day 1
and review oxidation vs.
reduction.
Assign oxidation numbers
(with help of class) to show
it is redox.
Teacher Does
Explore:
Learning Experience(s)
Time: __25____minutes
Handout General Plan for
Balancing Redox Reactions
and explain each step by
demonstrating the full
process (I do)
As a class, complete the
steps for balancing a redox
reaction equation together
(We do)
Probing Questions
Critical questions that will
guide students to a common
set of experiences.
This handout spells out the
steps for balancing redox
reactions.
What is the initial
unbalanced equation?
How do I assign ox #’s?
Why do we use halfreactions?
How do I balance charge?
Assign pairs of students
What is the initial overall
one of five redox reactions equation?
to balance. Each pair will
How do you find unknown
then join with the other
oxidation #’s?
pairs assigned the same
What are the halfreaction to compare
reactions?
solutions (You do)
I do:
HCl(aq) + HNO3(aq) HClO(aq) + NO(g)
We do:
Cr2O72-(aq) + Br-(aq)
You do:
Cu(s) + SO42-(aq) Cu2+(aq) + SO2(g)
Fe(s) + O2(aq) Fe3+(aq) + H2O
MnO4-(aq) + Fe2+(aq) Mn2+ + Fe3+
Br-(aq) + H2O2(aq) Br2(aq) + H2O
MnO2(s) + Cu+(aq) Mn2+(aq) + Cu2+(aq)
Teacher Does
Explain:
Learning Experience(s)
Time: __10____minutes
One representative from
each group will write the
solution on the board.
Student responses
Expected Student
Responses/Misconceptions
Determine from question
posed.
Use the toolkit rules.
They isolate the key ions or
atoms whose ox #’s change.
Add electrons to the more
positive side.
Varies.
Solve for unknowns using
the charge of atom/ion.
Varies.
Cr3+(aq) + Br2(l)
Probing Questions
Critical questions that will
help students clarify their
understanding and
introduce information
related to the lesson
concepts/skills.
How did you know which
atoms/ions to use in the half
reactions?
Student responses
Expected Student
Responses/Misconceptions
Change in oxidation
number from reactant to
product.
Why can you add H+ and
H2O into the reaction?
Reaction takes place in
acidic, aqueous solution.
How did you balance the
charge when you needed to
add different numbers of
electrons to the half
reactions?
Multiply the entire half
reaction(s) by an
appropriate number to
make them equal.
Probing Questions
Critical questions that will
help students extend or
apply their newly acquired
concepts/skills in new
situations.
Student responses
Expected Student
Responses/Misconceptions
Review definitions of
oxidation and reduction.
What is the difference
between oxidation and
reduction?
Oxidation: Losing
Electrons, increase in
oxidation number.
Reduction: Gaining
Electrons, decrease in
oxidation number.
Introduce terms: oxidizing
agent and reducing agent
What do you think an
oxidizing agent does?
A reducing agent?
Causes oxidation.
So if an oxidizing agent
causes oxidation, what do
you think happens to the
oxidizing agent?
What happens to the
reducing agent?
It is reduced.
Teacher Does
Extend / Elaborate:
Learning Experience(s)
Time: __5___minutes
Causes reduction.
It is oxidized.
Teacher Does
Evaluate:
Include summative
evaluation below.
Time: __5____minutes
Probing Questions
Critical questions that ask
students to demonstrate
their understanding of the
concepts and process skills.
These questions must
directly relate to the
lesson’s performance
objectives.
Student responses
Expected Student
Outcomes
Quiz (Mentor teacher will determine if this will be for a grade, so students should assume that it
is):
Use the half-reaction method to balance the following redox reaction in acidic, aqueous solution.
Show your steps clearly.
Ag ( s) NO3 (aq)
3 Ag ( s)
3 Ag (aq) 3e
Ag (aq) NO( g )
NO3 (aq) 4H 3 O (aq) 3e
3 Ag (s) NO3 (aq) 4H 3 O (aq)
NO( g ) 6H 2 O(l )
3 Ag (aq) NO( g ) 6H 2 O(l )
If time remains, pairs of students will be instructed to write a three-question quiz with separate
answer sheet on material from the two days. Pairs will then switch with another pair and each
will answer the other’s questions. Quizzes would then be handed in to check for misconceptions
or misunderstandings.