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.

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

Probing questions on relative energies of reactants and products in endothermic and exothermic and endothermic reactions.

student book

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

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Enthalpy Notation. Change of state.
CAT

By the end of the lesson, the learner should be able to:
Define the term enthalpy.
Distinguish positive enthalpy change from negative enthalpy change.

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

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.

Ice, naphthalene, thermometers, graph papers.

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

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.

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 displacement of ions.

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

Zinc, iron, magnesium, copper sulphate solution.

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.

Heat of solution hydration energy and lattice energy.

By the end of the lesson, the learner should be able to:
Define the terms lattice energy and hydration energy.
Explain the relationship between heat of solution, hydration energy.
Solve related problems.

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 60-64

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Heat values 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

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Environmental effects of fuels.

By the end of the lesson, the learner should be able to:
Outline some environmental effects of fuels.
Identify measures taken to reduce environmental
pollution.

Q/A & open discussion.

student book

K.L.B. BK IV
Pages 67-68

RATES OF REACTION & REVERSIBLE REACTIONS.

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

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

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.

Sodium thiosulphate heated at different temperatures, dilute HCl, stopwatches.
Graph papers.
Marble chips, marble chips powder, syringes, conical flasks with stoppers, 1M HCl.
Hydrogen peroxide, manganese (IV) oxide.

K.L.B. BK IV
Pages 80-83
K.L.B. BK IV
Pages 85-88

RATES OF REACTION & REVERSIBLE REACTIONS.

Effect of light on rate of specific reactions.

By the end of the lesson, the learner should be able to:
Identify reactions that are affected by light.

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

Silver bromide.

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

RATES OF REACTION & REVERSIBLE REACTIONS.

Reversible reactions.
State of equilibrium in chemical reactions.

By the end of the lesson, the learner should be able to:
Write down equations for reversible reactions.

Q/A: review temporary and permanent changes.
Teacher demonstration: heating crystals of hydrated copper (II) sulphate, then ?hydrating? them.
Write the corresponding chemical equations.
Give further examples of reversible reactions.

Crystals of hydrated copper (II) sulphate.
student book

K.L.B. BK IV
Pages 91-93

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.
The Haber Process.
The Contact Process.

By the end of the lesson, the learner should be able to:
Explain the effect of change of pressure & te,perature on equilibrium shift.
Explain the concept optimum conditions of a chemical equilibrium.
Explain factors that change the position of equilibrium of the Harber process.

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.

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.

student book

K.L.B. BK IV
Pages 97-101
K.L.B. BK IV
Pages 102-103

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.
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.
Predict whether a reaction will take place or not using standard electrode potentials.

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

Worked examples.
Oral exercise.
Assignment.

student book

K.L.B. BK IV
Pages 133-136
K.L.B. BK IV
Pages 136-137

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.

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.
Factors affecting electrolysis.
Application of electrolysis.

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

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

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

Sulphuric acid voltameter.
student book
Suitable voltameter.

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