ACIDS, BASES AND SALTS.

Strength of acids. Acids in aqueous form.
pH values of acids. Electrical conductivities of aqueous acids.
Definition of a base in terms of hydroxide ions.

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


Define an acid in terms of hydrogen ions.

Explain strength of acids in aqueous form in terms of number of hydrogen ions present.
Determine strength of acids using pH values.

Determine strengths of acids by comparing their electrical conductivities.

Classify acids as either strong or weak in terms of partial dissociations in aqueous solutions.

Class experiments: investigate reactions of magnesium and zinc carbonate with different acids.
Make and record observations in tabular form.
Make deductions from the observations.
Write relevant chemical equations and ionic equations.
Detailed discussion leading to the definition of an acid and explanation of strength of an acid.

Q/A: review determination of strength of acids using a litmus paper and pH scale.
Class / group experiments: record colour of universal indicator in
2M HCl and 2M ethanoic acid.
Set up voltameters of 2M HCl and 2M ethanoic acid in turns.
Record amounts of current .
Discuss the observations.
Write corresponding ionic equations.

Magnesium strip, zinc carbonate,
2M HCl,
2M H2SO4,
2M ethanoic acid.
Universal
indicator,
2M HCl,
2M ethanoic acid,
dry cells,
carbon electrodes,
milli-ammeters,
wires, switches etc.
Red litmus paper, calcium hydroxide solid.

K.L.B. BK IV
Pages 1-4
K.L.B. BK IV
Pages 4-6

ACIDS, BASES AND SALTS.

Neutralization reaction.
Strength of bases.

By the end of the lesson, the learner should be able to:
Determine the results of reaction of an acid and a base.

Add 1M HCl to an aqueous solution of Calcium hydroxide drop wise until colour, change of the universal indicator is noted.
Write ionic equation for the reaction.

1M HCl,
Calcium hydroxide,
universal indicator.
2M NaOH,
2M ammonia solution, universal indicator solutions, dry cells,
carbon electrodes,
milliammeters,
wires, switches etc

K.L.B. BK IV
Page 7

ACIDS, BASES AND SALTS.

Dissolving hydrogen chloride gas in water / methylbenzene.
Dissolving ammonia gas in water/ methylbenzene.

By the end of the lesson, the learner should be able to:
Define a polar and a non-polar solvent.

Teacher demonstration:
Dissolving HCl gas in different solvents.
Discuss the observations.
Write down related balanced chemical equations.

Ammonia gas,
Methylbenzene, hydrogen chloride gas.
Methylbenzene.

K.L.B. BK IV
Pages 9-11

ACIDS, BASES AND SALTS.

Amphoteric oxides.

By the end of the lesson, the learner should be able to:
Define an amphoteric oxide.
Identify some amphoteric oxides.

Class experiment:
Carry out acid / base reactions with metal oxides.
Q/A: make deductions from the results.
Writing and balancing relevant equations.

2M Nitric acid
2M NaOH,
HNO3.
Amphoteric oxides.

K.L.B. BK IV
Pages 12-14

ACIDS, BASES AND SALTS.

Precipitation Reactions.

By the end of the lesson, the learner should be able to:
Define a precipitate.
Write ionic equations showing formation of precipitates.

Q/A: review definition of a salt.
Class experiment;
Add sodium carbonate or a suitable carbonate to various salt solutions containing Mg2+, Al3+, Ca2+, etc.
Make observations and discuss the results.

Soluble carbonates e.g. Na2CO3, K2CO3, (NH4)2CO3
Salt solutions containing Mg2+, Al3+, Ca2+, etc.

K.L.B. BK IV
Pages 14-16

ACIDS, BASES AND SALTS.

Solubility of chlorides sulphites and sulphates.
Equations for formation of insoluble chlorides, sulphites and sulphates.
Complex ions.

By the end of the lesson, the learner should be able to:
Find out cations that form (in)soluble chlorides, sulphates and sulphites.
Explain formation of complex ions.

Class experiments: measure 2cc of 0.1M solution containing Pb2+ into a test tube.
Add drops of 2M NaCl solution.
(Later 2M Sodium Sulphate and 2M Sodium Sulphate).
Warm the mixture and make observations.
Repeat the procedure using other salt solutions containing other ions.
Tabulate the results.


Add drops of 2M sodium hydroxide / 2M ammonia solution to a solution containing Mg2+, Zn2+, etc.

Make observations and discuss the results.

0.1M solution containing Pb2+, 2M NaCl solution, 2M sodium sulphate, source of heating.
student book
2M Sodium hydroxide (2M ammonia solution),
solution containing Mg2+, Zn2+, etc.

K.L.B. BK IV
Pages 16-17
K.L.B. BK IV
Pages 18-20

ACIDS, BASES AND SALTS.

Solubility of a salt at a given temperature.
Problems solving on solubility.

By the end of the lesson, the learner should be able to:
Define the term solubility.
Determine solubility of a given salt at room temperature.

Q/A: review the terms saturated, unsaturated solutions & crystallization.
Class experiment: determine mass of a solute that dissolves in 100cc of water at room temperature.

Suitable solutes.
Evaporating dish, watch glass, heating source, thermometer.

K.L.B. BK IV
Pages 20-21

ACIDS, BASES AND SALTS.

Effect of temperature on solubility of a solute in a solvent.

By the end of the lesson, the learner should be able to:
Investigate the effect of temperature on solubility of a solute in a solvent.

Experiments involving solubility of KClO3 at different temperatures.
Note temperatures at which crystallization occurs.
Oral questions and discussion.

KClO3 thermometers, source of heat.

K.L.B. BK IV
Pages 22-25

ACIDS, BASES AND SALTS.

Effects of various salts on soap.
Removal of hardness of water.

By the end of the lesson, the learner should be able to:
Determine the effects of various salts on soap.

Group experiments: form soap lather in distilled water, tap water, rainwater, dilute solution of sodium chloride and solutions containing Ca2+ and Zn2+.
Note volume of soap that forms lather readily.

distilled water, tap water, rainwater, dilute solution of sodium chloride and solutions containing Ca2+ and Zn2+.
student book

K.L.B. BK IV
Pages 25-27

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Endothermic and Exothermic Reactions.
Energy level diagrams.

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.
student book

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

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.

Enthalpy Notation. Change of state.
CAT
Molar heat of solution.

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.

Determine molar heat of solution of given substances.

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.


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

Ice, naphthalene, thermometers, graph papers.
Ammonia nitrate / sodium hydroxide, thermometers.

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

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.

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

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

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.
Heat of solution hydration energy and lattice energy.
Heat values of fuels.

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

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.

Probing questions and brief discussion.

student book

K.L.B. BK IV
Pages 56-57
K.L.B. BK IV
Pages 64-66

ENERGY CHANGES IN PHYSICAL & CHEMICAL PROCESSES.
RATES OF REACTION & REVERSIBLE REACTIONS.

Environmental effects of fuels.
Effect of concentration on rate of a reaction

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
Portions of 2M HCl diluted with different volumes of water,
Stopwatches.

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

RATES OF REACTION & REVERSIBLE REACTIONS.

Effect of time of reaction on the rate of reaction.
Effect of temperature of reactants on rate of reaction.

By the end of the lesson, the learner should be able to:
Explain how the rate or reaction changes as the reaction proceed

Group experiments: investigate volume of gas evolved when magnesium reacts with dilute HCl.
Collect evolved gas and sketch and illustrative graphs.
Discuss the results.

Magnesium ribbons, stopwatches, conical flask.
100cm3 0.5M HCl, syringes, stoppers, tubes and connectors.
Sodium thiosulphate heated at different temperatures, dilute HCl, stopwatches.
Graph papers.

K.L.B. BK IV
Pages 75-79

RATES OF REACTION & REVERSIBLE REACTIONS.

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 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.
Hydrogen peroxide, manganese (IV) oxide.

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

RATES OF REACTION & REVERSIBLE REACTIONS.

Effect of light on rate of specific reactions.
Reversible 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.
Crystals of hydrated copper (II) sulphate.

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

RATES OF REACTION & REVERSIBLE REACTIONS.

State of equilibrium in chemical reactions.
Le Chatelier?s Principle.
Effect of change of pressure and temperature on equilibrium shift.

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.

State Le Chatelier?s Principle.

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

student book
Add 2M sodium hydroxide,
student book

K.L.B. BK IV
Pages 94-95
K.L.B. BK IV
Pages 95-97

RATES OF REACTION & REVERSIBLE REACTIONS.

The Haber Process.
The Contact Process.

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.

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 102-103

ELECTRO-CHEMISTRY.

Redox reactions.
Oxidizing Numbers.

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.

Displacement reactions.
The oxidizing power of an element.

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+.
Halogens:
Cl2 (g),
Br2 (l),
I2 (s).
Halides:
KCl, KBr, KI.

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

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.

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

Zinc/ copper cell.
student book

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

ELECTRO-CHEMISTRY.

Standard electrode potential series.
Emf of a cell.
Possibility of a reaction to take place.

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.
Calculate emf of a cell using standard electrodes potentials.

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

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

student book

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

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.
Brine voltameter.

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

ELECTRO-CHEMISTRY.

Electrolysis of dilute sulphuric (VI) acid.
Factors affecting electrolysis.

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.
student book

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

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

METALS

Ores of some metals.
Occurrence and extraction of sodium.
Occurrence and extraction of aluminium.
Occurrence and extraction of iron.

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


Name the chief ores of some metals.


Describe occurrence and extraction of aluminium.

Exposition and brief discussion.
Brief discussion.
Write relevant chemical equations.

Chart: Down?s cell.
student book
Chart: Blast furnace.

K.L.B. BK IV
Pages 168-9
K.L.B. BK IV
Pages 171-3

METALS

Occurrence and extraction of zinc.

By the end of the lesson, the learner should be able to:
Describe occurrence and extraction of zinc by electrolysis and reduction methods.

Brief discussion.
Write relevant chemical equations.

Flow chart: extraction of Zinc.

K.L.B. BK IV
Pages 175-9

METALS

Extraction of lead.
Occurrence and extraction of copper.

By the end of the lesson, the learner should be able to:
Explain how lead is extracted.

Q/A & brief discussion.
Write balanced chemical equations leading to extraction of lead.

Flow chart: extraction of lead.
Flow chart: extraction of copper.

K.L.B. BK IV
Pages 179-80

METALS

Physical properties of some metals.

By the end of the lesson, the learner should be able to:
State general properties of metals.
Explain the difference in physical properties of metals.

Compare physical properties of some metals as summarized in a chart.
Q/A & discussion based on physical properties.

student book

K.L.B. BK IV
Pages 183-4

METALS

Reaction of metals with oxygen.
Reaction of metals with cold water and steam.

By the end of the lesson, the learner should be able to:
Explain effect of burning metals in air.

Teacher demonstration / Group experiments.
Burning some metals in air.
Write relevant equations.
Brief discussion.

Common lab. metals.
Metals: Al, Zn, Fe, Cu.

K.L.B. BK IV
Pages 184-6

METALS

Reaction of metals with chlorine.
Reaction of metals with acids.
Uses of metals.

By the end of the lesson, the learner should be able to:
Describe the reaction of metals with chlorine.
Describe and explain reaction of metals with acids.

Teacher demonstration in a fume cupboard / in the open.
Investigate reaction of metals with chorine
Write corresponding equations.


Group experiments: investigate reaction of metals with dilute acids.
Teacher demonstration: investigate reaction of metals with concentrated acids.
Discuss the observations made and write relevant chemical equations.

Metals: Al, Zn, Fe, Cu.
Metals: Al, Zn, Fe, Cu.
Acids; HCl, HNO3, H2SO4.
student book

K.L.B. BK IV
Pages 189-191
K.L.B. BK IV
Pages 191-4

METALS
ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Environmental effects of extraction of metals.
Physical properties of alkanols.

By the end of the lesson, the learner should be able to:
Identify some environmental effects of extraction of metals.

Oral questions and open discussion.

Assignment / Topic review.

student book

K.L.B. BK IV
Pages 197-8

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Chemical properties of alkanols.

By the end of the lesson, the learner should be able to:
Describe some chemical reactions of alkanols.

Group experiments/ teacher demonstration to investigate combustion of ethanol and its reaction with metals.
Write corresponding chemical equations.

student book

K.L.B. BK IV
Pages 213-5

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Esters and esterification.
Oxidation of ethanol. Uses of alkanols.

By the end of the lesson, the learner should be able to:
Explain formation of esters.
Describe the esterification process.

Teacher exposes and explains new concepts.

Assignment.

student book

K.L.B. BK IV
Pages 215-6

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Alkanoic (Carboxylic Acids).

By the end of the lesson, the learner should be able to:
Identify the functional group of alkanoic (carboxylic) acids.
Explain formation of alkanoic acid molecule.

Q/A: review functional group of alkanols.

Brief discussion.

student book

K.L.B. BK IV
Page 219

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Nomenclature of alkanoic acids.
Lab preparation of ethanoic acid.
Physical properties of alkanoic acids.
Chemical properties of alkanoic acids.

By the end of the lesson, the learner should be able to:
Name and draw the structure of simple alkanoic acids.


Explain some physical properties of alkanoic acids.

Guided discovery of the naming system for alkanoic acids.
Compare physical properties of some alkanoic acids.
Discuss the difference in physical properties among alkanoic acids.

Chart: homologous series of alkanoic acids.
Concentrated H2SO4, potassium manganate
(VII) Crystals, water bath.
student book
Ethanoic acid, universal indicator, sodium carbonate, magnesium strip, ethanol, conc. H2SO4 and sodium hydroxide.

K.L.B. BK IV
Pages 219-221
K.L.B. BK IV
Pages 223-4

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Chemical properties & Uses of alkanoic acids.

By the end of the lesson, the learner should be able to:
Write equations for chemical reactions involving acids.
State uses of alkanoic acids.

Review and discuss the observations above.
Write corresponding chemical equations.
Teacher elucidates uses of alkanoic acids.

student book

K.L.B. BK IV
Pages 225-7

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Soap preparation in the lab.
Cleaning action of soap.

By the end of the lesson, the learner should be able to:
Describe soap preparation in the lab.

Group experiments,
Answer questions based on the experiments already carried out.

student book

K.L.B. BK IV
Pages 227-230

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)

Effects of hard / soft water on soap.
Soapless detergents.

By the end of the lesson, the learner should be able to:
Explain the effects of hard/ soft water on soap.

Group experiments: form soap lather in different solutions.

Deduce the effects of hard/ soft water on soap.

Distilled water, tap water, rainwater, sodium chloride solution.
Calcium nitrate, Zinc Sulphate, etc.
student book

K.L.B. BK IV
Pages 232-235

ORGANIC CHEMISTRY II (ALKANES & ALKANOIC ACIDS)
RADIOACTIVITY

Polymers and polymerization.
Definition of radioactivity.

By the end of the lesson, the learner should be able to:
Explain the concepts additional and condensation polymerization as methods of making synthetic polymers.
Identify some products of polymerization.
State merits and demerits of synthetic polymers over natural materials.

Teacher exposes and explains new concepts.

Detailed discussion.

Assignment.

student book

K.L.B. BK IV
Pages 238-242

RADIOACTIVITY

Alpha particles.
Equations involving alpha particles.
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 alpha particles.
Describe methods of detecting alpha particles.

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

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

Expository approach:


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