ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Endothermic and Exothermic Reactions.

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






To differentiate between endothermic & exothermic reactions.

Investigate temperature changes in solution formation.

Obtain changes in temperature when ammonium nitrate and sodium hydroxide are dissolved in water, one at a time.

Ammonium nitrate,
Sodium hydroxide, thermometers.

K.L.B. BK IV
Pages 32-33

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Energy level diagrams.
Enthalpy Notation. Change of state.

By the end of the lesson, the learner should be able to:
Represent endothermic reactions with exothermic reactions with energy level diagrams.

Define the term enthalpy.
Distinguish positive enthalpy change from negative enthalpy change.

Determine the M.P/ B.P of a pure substance.

Probing questions on relative energies of reactants and products in endothermic and exothermic and endothermic reactions.
Q/A and brief discussion.
Class experiments: determine B.P of pure water/ M.P of naphthalene / ice.
Use experimental results to plot temperature-time graphs.
Explain the shape of the graphs.
Q/A: review kinetic theory of matter.
Apply the theory to explain the shape of the graph, and nature of bonding in substances.

student book
Ice, naphthalene, thermometers, graph papers.

K.L.B. BK IV
Pages 33-35
K.L.B. BK IV
Pages 35-39

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

CAT

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

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Molar heat of solution.

By the end of the lesson, the learner should be able to:
Determine molar heat of solution of given substances.

Dissolve known masses of ammonia nitrate / sodium hydroxide in known volumes of water.
Determine temperature changes.
Calculate molar heat of solution. Supervised practice.

Ammonia nitrate / sodium hydroxide, thermometers.

K.L.B. BK IV
Pages 40-41

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Molar heat of solution of H2SO4.

By the end of the lesson, the learner should be able to:
Determine molar heat of solution of H2SO4.

Dissolve some known volume of conc. H2SO4 in a given volume of water.
Note the change in temperature.
Work out the molar heat of solution of H2SO4.

Conc. H2SO4, thermometers.

K.L.B. BK IV
Pages 42-45

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Enthalpy of combustion. Enthalpy of combustion.
Molar heat of displacement of ions.

By the end of the lesson, the learner should be able to:
Define the term enthalpy of combustion.
Determine the enthalpy of combustion of ethanol.
Explain why actual heats of combustion are usually lower than the theoretical values.

Define the term molar heat of solution of displacement of ions.
Determine the molar heat of solution of displacement of ions.

Group experiments / teacher demonstration.

Obtain and record results.


Work out calculations.
Group experiments/ teacher demonstration.
Note steady temperature of solutions formed when zinc/ iron / magnesium reacts with copper sulphate solution.
Work out the molar heat of displacement of a substance from a solution of its ions.

Ethanol, distilled water, thermometer, clear wick, tripod stand and wire gauze.
Zinc, iron, magnesium, copper sulphate solution.

K.L.B. BK IV
Pages 45-48
K.L.B. BK IV
Pages 48-50

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Molar heat of solution of neutralization.

By the end of the lesson, the learner should be able to:
Define the term neutralization.
Determine the molar heat of neutralization of HCl with NaOH.

Class experiments:
Neutralize 2M HCl of known volume with a determined volume of 1M / 2M sodium hydroxide.
Note highest temperature of the solution.
Work out the molar heat of neutralization.
Solve other related problems.
Assignment.

2M HCl of known volume, 1M / 2M sodium hydroxide.

K.L.B. BK IV
Pages 50-53

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Standard enthalpy changes.

By the end of the lesson, the learner should be able to:
Define the term standard enthalpy change.
Denote standard enthalpy change with the correct notation.

Exposition & brief discussion.

student book

K.L.B. BK IV
Pages 54-56

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Hess?s Law.

By the end of the lesson, the learner should be able to:
State Hess?s law.

Solve problems related to Hess?s law.

Detailed discussion & guided discovery of the law.
Illustrations of energy cycles and energy levels leading to Hess?s law.
Worked examples.
Supervised practice
Written assignment.

student book

K.L.B. BK IV
Pages 56-57

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Hess?s Law.
Heat of solution hydration energy and lattice energy.

By the end of the lesson, the learner should be able to:
State Hess?s law.

Solve problems related to Hess?s law.
Define the terms lattice energy and hydration energy.
Explain the relationship between heat of solution, hydration energy.
Solve related problems.

Detailed discussion & guided discovery of the law.
Illustrations of energy cycles and energy levels leading to Hess?s law.
Worked examples.
Supervised practice
Written assignment.

Exposition of new concepts.
Guided discovery of the relationship between heat solution hydration energy and lattice energy.
Worked examples.
Assignment.

student book

K.L.B. BK IV
Pages 56-57
K.L.B. BK IV
Pages 60-64

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Heat values of fuels.
Environmental effects of fuels.

By the end of the lesson, the learner should be able to:
Define the term fuel.
Describe energy changes when a fuel undergoes combustion.
Outline factors considered when choosing a suitable fuel.

Probing questions and brief discussion.

student book

K.L.B. BK IV
Pages 64-66

RATES OF REACTION & REVERSIBLE REACTIONS.

Effect of temperature of reactants on rate of reaction.

By the end of the lesson, the learner should be able to:
Explain the effect of temperature on rate of reaction.

Group experiments: investigate the effects of temperature on the rate of reaction of sodium thiosulphate with dilute HCl.
Sketch and interpret relevant graphs.
Discuss the collision theory and effects of activation energy.

Sodium thiosulphate heated at different temperatures, dilute HCl, stopwatches.
Graph papers.

K.L.B. BK IV
Pages 80-83

RATES OF REACTION & REVERSIBLE REACTIONS.

Effect of change in surface area of reactants on the rate of a reaction.

By the end of the lesson, the learner should be able to:
Explain the effect of change in surface area on the rate of a reaction.

Group experiment/ teacher demonstration.

Compare reactions of marble chips with dilute HCl and that of marble chips powder with equally diluted HCl.

Collect evolved gas in each case.

Teacher asks probing questions related to the observations made.

Marble chips, marble chips powder, syringes, conical flasks with stoppers, 1M HCl.

K.L.B. BK IV
Pages 83-85

RATES OF REACTION & REVERSIBLE REACTIONS.

Effect of a suitable catalyst on the rate of a reaction
Effect of light on rate of specific reactions.
Reversible reactions.

By the end of the lesson, the learner should be able to:
Explain effects of a suitable catalyst on the rate of a reaction.
Identify reactions that are affected by light.

Teacher demonstration: preparation and collection of oxygen gas without using a catalyst, then using manganese (IV) oxide as a catalyst.
Explain the results in terms of activation energy.

Teacher demonstration: decomposition of silver bromide in the presence of light.
Mention other examples of reactions affected by light.

Hydrogen peroxide, manganese (IV) oxide.
Silver bromide.
Crystals of hydrated copper (II) sulphate.

K.L.B. BK IV
Pages 85-88
K.L.B. BK IV
Pages 89-91

RATES OF REACTION & REVERSIBLE REACTIONS.

State of equilibrium in chemical reactions.

By the end of the lesson, the learner should be able to:
Define the term equilibrium as used in reversible reactions.
Write down equations of reversible reactions in a state of equilibrium.

Brief discussion, giving examples of chemical equations for reversible reactions.

student book

K.L.B. BK IV
Pages 94-95

RATES OF REACTION & REVERSIBLE REACTIONS.

Le Chatelier?s Principle.

By the end of the lesson, the learner should be able to:
State Le Chatelier?s Principle.

Investigate the effect of change of concentration of reactants on equilibrium.
Add 2M sodium hydroxide in steps to bromine water.
Make and record observations.
Discuss the results leading to
Le Chatelier?s Principle.

Add 2M sodium hydroxide,

K.L.B. BK IV
Pages 95-97

RATES OF REACTION & REVERSIBLE REACTIONS.

Effect of change of pressure and temperature on equilibrium shift.

By the end of the lesson, the learner should be able to:
Explain the effect of change of pressure & te,perature on equilibrium shift.

Q/A: review kinetic theory of matter.
Q/A & discussion on effect of change of pressure / temperature on shifting of equilibrium; giving specific examples of chemical equations.
Written assignment.

student book

K.L.B. BK IV
Pages 97-101

RATES OF REACTION & REVERSIBLE REACTIONS.
ELECTRO-CHEMISTRY.

The Haber Process.
The Contact Process.
Redox reactions.

By the end of the lesson, the learner should be able to:
Explain the concept optimum conditions of a chemical equilibrium.
Explain factors that change the position of equilibrium of the Harber process.



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

Q/A and detailed discussion on change of pressure, temperature, concentration of ammonia and effect of presence of a suitable catalyst on the Haber process.


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 102-103
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.

By the end of the lesson, the learner should be able to:
Arrange elements in order of their oxidizing power.

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.

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

Halides:
KCl, KBr, KI.

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

ELECTRO-CHEMISTRY.

Cell diagrams.
Standard Electrode Potentials.

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

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

Descriptive and expository approaches: teacher exposes new concepts.

Zinc/ copper cell.

student book

K.L.B. BK IV
Pages 123-128
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.
Possibility of a reaction to take place.

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.

Primary and secondary chemical cells.

By the end of the lesson, the learner should be able to:
Describe the functioning of primary and secondary chemical cells.

Exposition of new concepts and brief discussion
Assignment.

student book

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

ELECTRO-CHEMISTRY.

Electrolysis of dilute NaCl.
Electrolysis of brine.

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

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.

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

Dilute sodium chloride voltameter.
Brine voltameter.

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

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

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.

student book

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

ELECTRO-CHEMISTRY.

Application of electrolysis.
Faraday?s law of electrolysis.

By the end of the lesson, the learner should be able to:
Describe some applications of electrolysis.

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

Suitable voltameter.
Weighing balance, stop watch, copper sulphate voltameter.

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

RADIOACTIVITY

Definition of radioactivity.
Alpha particles.
Equations involving alpha particles.

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.


State properties of alpha particles.
Describe methods of detecting alpha particles.

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.


Q/A: position of helium in the periodic table.

Expository approach:

student book

K.L.B. BK IV
Pages 249-251
K.L.B. BK IV
Pages 251-253

RADIOACTIVITY

Beta particles. Gamma rays.
Radioactive Half-Life.

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.

Q/A: Review isotopes.
Expository approach: teacher briefly exposes new concepts.
Examples of equations.
Supervised practice.

Assignment.

student book
Dice.

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

RADIOACTIVITY

Radioactive decay curve.
Nuclear fusion and nuclear fission. Applications of radioactivity.

By the end of the lesson, the learner should be able to:
Plot a radioactive decay curve to deduce the
half ?life from the curve.

Drawing a radioactive decay curve inferring the half-life of the sample from the graph.

Graph papers.
student book

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