ELECTRO-CHEMISTRY.

Redox reactions.

By the end of the lesson, the learner should be able to:


Describe redox reactions in terms of gain / loss of electrons.
Identify oxidizing / reducing agents involved in redox reactions.

Q/A: review cations, anions and charges.
Write down ionic half equations and identify reducing / oxidizing agents.

student book

K.L.B. BK IV
Pages 108-9

ELECTRO-CHEMISTRY.

Oxidizing Numbers.

By the end of the lesson, the learner should be able to:
Outline rules of assigning oxidation numbers.
Determine the oxidation numbers of an element in a given compound.
Explain the use of oxidation numbers in naming compounds.

Exposition and giving specific examples.
Work out oxidizing number of elements in given compounds.
Copy and complete a table of compounds containing elements that more than one oxidation number.

student book

K.L.B. BK IV
Pages 109-116

ELECTRO-CHEMISTRY.

Displacement reactions.

By the end of the lesson, the learner should be able to:
Explain change of oxidation numbers during redox / displacement reactions. Arrange elements in order of their reducing power.

Class standard experiments: reacting metals with solutions containing metal ions.
Taking note of reactions and those that do not take place; and tabulating the results.

Metals: Ca, Na, Zn, Fe, Pb, and Cu.
Solutions containing Ca2+, Mg2+, Zn2+, Fe2+.

K.L.B. BK IV
Pages 116-120

ELECTRO-CHEMISTRY.

The oxidizing power of an element.
Cell diagrams.

By the end of the lesson, the learner should be able to:
Arrange elements in order of their oxidizing power.
Define the terms electrode, potential and e.m.f. of an electrochemical cell.
Describe components of a cell diagram.
Draw cell diagrams using correct notations.

Teacher demonstration / group expts:
Adding halogens to solutions containing halide ions.
Tabulate the results.
Discuss the results and arrive at the oxidizing power series of halogens.

Teacher demonstration: Zinc/ copper cell.
Q/A & discussion: changes in oxidation numbers.
Exposition: cell diagram and deducing the direction of electron flow.

Halogens:
Cl2 (g),
Br2 (l),
I2 (s).

Halides:
KCl, KBr, KI.
Zinc/ copper cell.

K.L.B. BK IV
Pages 120-122
K.L.B. BK IV
Pages 123-128

ELECTRO-CHEMISTRY.

Standard Electrode Potentials.

By the end of the lesson, the learner should be able to:
Identify standard conditions for measuring electrode potentials.
Define the term standard electrode potential of a cell.
Write half reactions of electrochemical cells.

Descriptive and expository approaches: teacher exposes new concepts.

student book

K.L.B. BK IV
Pages 129-131

ELECTRO-CHEMISTRY.

Standard electrode potential series.

By the end of the lesson, the learner should be able to:
Recall the order of standard electrode potentials.
Compare oxidizing and reducing powers of substances.

Q/A: review reactivity series, oxidizing agent, reducing agent.
Exposition: the order of standard electrode potentials.
Discussion: oxidizing and reducing powers of substances.

student book

K.L.B. BK IV
Pages 131-133

ELECTRO-CHEMISTRY.

Emf of a cell.

By the end of the lesson, the learner should be able to:
Calculate emf of a cell using standard electrodes potentials.

Q/A: review half-cells.
Worked examples; supervised practice.
Assignment.

student book

K.L.B. BK IV
Pages 133-136

ELECTRO-CHEMISTRY.

Possibility of a reaction to take place.
Primary and secondary chemical cells.

By the end of the lesson, the learner should be able to:
Predict whether a reaction will take place or not using standard electrode potentials.


Describe the functioning of primary and secondary chemical cells.

Worked examples.
Oral exercise.
Assignment.
Exposition of new concepts and brief discussion
Assignment.

student book

K.L.B. BK IV
Pages 136-137
K.L.B. BK IV
Pages 138-141

ELECTRO-CHEMISTRY.

Electrolysis of dilute NaCl.

By the end of the lesson, the learner should be able to:
Define the term electrolysis.
Explain the concept of preferential discharge of ions.

Teacher demonstration: electrolysis of dilute sodium chloride with carbon electrodes.
Test for gases collected.
Write down equations of reactions at each electrode.
Discussion: preferential discharge of ions at electrodes.

Dilute sodium chloride voltameter.

K.L.B. BK IV
Pages 141-144

ELECTRO-CHEMISTRY.

Electrolysis of brine.

By the end of the lesson, the learner should be able to:
Identify products of electrolysis of brine.

Teacher demonstration/ group experiments.
Test for the products of electrolysis.
Write relevant equations.

Brine voltameter.

K.L.B. BK IV
Pages 144-146

ELECTRO-CHEMISTRY.

Electrolysis of dilute sulphuric (VI) acid.

By the end of the lesson, the learner should be able to:
Identify products of electrolysis of dilute sulphuric (VI) acid.

Teacher demonstration/ group experiments.
Test for the products of electrolysis.
Write relevant equations.

Sulphuric acid voltameter.

K.L.B. BK IV
Pages 146-148

ELECTRO-CHEMISTRY.

Factors affecting electrolysis.
Application of electrolysis.

By the end of the lesson, the learner should be able to:
Explain factors that affect electrolytic products discharged at electrodes.
Describe some applications of electrolysis.

Q/A: review the electrochemical series of elements.
Teacher writes down order of ease of discharge of ions at electrodes.
Discussion: other factors; giving suitable examples.

Probing questions and brief discussion on applications of electrolysis.
Practical assignment on electrolysis: electroplating an iron nail with a suitable metal.

student book
Suitable voltameter.

K.L.B. BK IV
Pages 153-5
K.L.B. BK IV
Pages 155-7

ELECTRO-CHEMISTRY.

Faraday?s law of electrolysis.

By the end of the lesson, the learner should be able to:
State Faraday?s law of electrolysis.
Solve problems related to Faraday?s law of electrolysis.

Discuss above results, leading to Faraday?s law of electrolysis.

Worked examples.

Assignment.

Weighing balance, stop watch, copper sulphate voltameter.

K.L.B. BK IV
Pages 161-4

RADIOACTIVITY

Definition of radioactivity.

By the end of the lesson, the learner should be able to:


Define radioactivity, a nuclide and radioactive decay.
Differentiate between natural and artificial radioactivity.

Q/A: Review the atomic structure.
Exposition: symbolic representation of an atom / nucleus.
Exposition: meaning of radioactivity and radioactive decay.
Discussion: artificial and natural radioactivity.

student book

K.L.B. BK IV
Pages 249-251

RADIOACTIVITY

Alpha particles.
Equations involving alpha particles.

By the end of the lesson, the learner should be able to:
State properties of alpha particles.
Describe methods of detecting alpha particles.
Write down and balance equations involving alpha particles.

Q/A: position of helium in the periodic table.
Expository approach:
Q/A: Review atomic and mass numbers.
Examples of balanced equations.
Supervised practice.

student book

K.L.B. BK IV
Pages 251-253

RADIOACTIVITY

Beta particles. Gamma rays.
Radioactive Half-Life.
Radioactive decay curve.
Nuclear fusion and nuclear fission. Applications of radioactivity.

By the end of the lesson, the learner should be able to:
State properties of beta particles.
Define isotopes and isobars.
Write down balanced equations involving both alpha and beta particles.
State properties of gamma rays.
Define the term radioactive half-life. Solve problems relating to half ?life
Plot a radioactive decay curve to deduce the
half ?life from the curve.
Differentiate between nuclear fusion and nuclear fission.
Describe applications of radioactivity.

Q/A: Review isotopes.
Expository approach: teacher briefly exposes new concepts.
Examples of equations.
Supervised practice.
Assignment.
Teacher demonstration: Dice experiment.
Exposition of the term half-life.
Worked examples.
Written exercise
Drawing a radioactive decay curve inferring the half-life of the sample from the graph.
Exposition of new concepts accompanied by nuclear equations.
Brief discussion: Carbon dating, detecting leakage, medication, agriculture, industry; effect of static charges, etc.

student book
Dice.
Graph papers.
student book

K.L.B. BK IV
Pages 251-253
K.L.B. BK IV
Pages 254-5