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.

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.

CAT
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.

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.

Group experiments / teacher demonstration.

Obtain and record results.


Work out calculations.

Ethanol, distilled water, thermometer, clear wick, tripod stand and wire gauze.

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

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Molar heat of displacement of ions.
Molar heat of solution of neutralization.

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.
Define the term neutralization.
Determine the molar heat of neutralization of HCl with NaOH.

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.

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.

Zinc, iron, magnesium, copper sulphate solution.

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

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

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.
Heat values of fuels.

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.

Define the term fuel.
Describe energy changes when a fuel undergoes combustion.
Outline factors considered when choosing a suitable fuel.

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

Probing questions and brief discussion.

student book

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

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.

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

Expository approach:

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.

Plot a radioactive decay curve to deduce the
half ?life from the curve.

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

Assignment.

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

student book
Dice.
Graph papers.
student book

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