ORGANIC CHEMISTRY II

Introduction to Alkanols and Nomenclature

By the end of the lesson, the learner should be able to:
Define alkanols and identify functional group
- Apply nomenclature rules for alkanols
- Draw structural formulae of simple alkanols
- Compare alkanols with corresponding alkanes

Q/A: Review alkanes, alkenes from Form 3
- Study functional group -OH concept
- Practice naming alkanols using IUPAC rules
- Complete Table 6.2 - alkanol structures

Molecular models, Table 6.1 and 6.2, alkanol structure charts, student books

KLB Secondary Chemistry Form 4, Pages 167-170

ORGANIC CHEMISTRY II

Isomerism in Alkanols
Laboratory Preparation of Ethanol
Industrial Preparation and Physical Properties
Chemical Properties of Alkanols I
Chemical Properties of Alkanols II

By the end of the lesson, the learner should be able to:
Explain positional and chain isomerism
- Draw isomers of given alkanols
- Name different isomeric forms
- Classify isomers as primary, secondary, or tertiary
Explain hydration of ethene method
- Compare laboratory and industrial methods
- Analyze physical properties of alkanols
- Relate properties to molecular structure

Study positional isomerism examples (propan-1-ol vs propan-2-ol)
- Practice drawing chain isomers
- Exercises on isomer identification and naming
- Discussion on structural differences
Study ethene hydration using phosphoric acid catalyst
- Compare fermentation vs industrial methods
- Analyze Table 6.3 - physical properties
- Discussion on hydrogen bonding effects

Isomer structure charts, molecular models, practice worksheets, student books
Sugar, yeast, warm water, conical flask, delivery tube, lime water, thermometer
Table 6.3, industrial process diagrams, ethene structure models, property comparison charts
Ethanol, sodium metal, universal indicator, concentrated H₂SO₄, ethanoic acid, test tubes
Acidified potassium chromate/manganate, ethanoic acid, concentrated H₂SO₄, heating apparatus

KLB Secondary Chemistry Form 4, Pages 170-171
KLB Secondary Chemistry Form 4, Pages 171-173

ORGANIC CHEMISTRY II

Uses of Alkanols and Health Effects
Introduction to Alkanoic Acids
Laboratory Preparation of Ethanoic Acid

By the end of the lesson, the learner should be able to:
State various uses of alkanols
- Explain health effects of alcohol consumption
- Discuss methylated spirits
- Analyze alcohol in society

Discussion on alkanol applications as solvents, fuels, antiseptics
- Health effects of alcohol consumption
- Methylated spirits composition
- Social implications

Charts showing alkanol uses, health impact data, methylated spirit samples, discussion materials
Alkanoic acid structure charts, Table 6.5 and 6.6, molecular models, student books
Ethanol, KMnO₄, concentrated H₂SO₄, distillation apparatus, thermometer, round-bottom flask

KLB Secondary Chemistry Form 4, Pages 176-177

ORGANIC CHEMISTRY II

Physical and Chemical Properties of Alkanoic Acids

By the end of the lesson, the learner should be able to:
Investigate chemical reactions of ethanoic acid
- Test with various reagents
- Write chemical equations
- Analyze acid strength

Experiment following Table 6.8: Test ethanoic acid with indicators, metals, carbonates, bases
- Record observations
- Write equations
- Discuss weak acid behavior

2M ethanoic acid, universal indicator, Mg strip, Na₂CO₃, NaOH, phenolphthalein, test tubes

KLB Secondary Chemistry Form 4, Pages 180-182

ORGANIC CHEMISTRY II

Esterification and Uses of Alkanoic Acids

By the end of the lesson, the learner should be able to:
Explain ester formation process
- Write esterification equations
- State uses of alkanoic acids
- Prepare simple esters

Complete esterification experiments
- Study concentrated H₂SO₄ as catalyst
- Write general esterification equation
- Discuss applications in food, drugs, synthetic fibres

Ethanoic acid, ethanol, concentrated H₂SO₄, test tubes, heating apparatus, cold water

KLB Secondary Chemistry Form 4, Pages 182-183

ORGANIC CHEMISTRY II

Introduction to Detergents and Soap Preparation
Mode of Action of Soap and Hard Water Effects
Soapless Detergents and Environmental Effects

By the end of the lesson, the learner should be able to:
Define detergents and classify types
- Explain saponification process
- Prepare soap in laboratory
- Compare soapy and soapless detergents
Explain soapless detergent preparation
- Compare advantages/disadvantages
- Discuss environmental impact
- Analyze pollution effects

Study soap vs soapless detergent differences
- Experiment 6.5: Saponify castor oil with NaOH
- Add salt for salting out
- Test soap formation
Study alkylbenzene sulphonate preparation
- Compare Table 6.9 - soap vs soapless
- Discussion on eutrophication and biodegradability
- Environmental awareness

Castor oil, 4M NaOH, NaCl, evaporating dish, water bath, stirring rod, filter paper
Soap samples, distilled water, hard water (CaCl₂/MgSO₄ solutions), test tubes, demonstration materials
Flow charts of detergent manufacture, Table 6.9, environmental impact data, sample detergents

KLB Secondary Chemistry Form 4, Pages 183-186
KLB Secondary Chemistry Form 4, Pages 188-191

ORGANIC CHEMISTRY II

Introduction to Polymers and Addition Polymerization

By the end of the lesson, the learner should be able to:
Define polymers, monomers, and polymerization
- Explain addition polymerization
- Draw polymer structures
- Calculate polymer properties

Study polymer concept and terminology
- Practice drawing addition polymers from monomers
- Examples: polyethene, polypropene, PVC
- Calculate molecular masses

Polymer samples, monomer structure charts, molecular models, calculators, polymer formation diagrams

KLB Secondary Chemistry Form 4, Pages 191-195

ORGANIC CHEMISTRY II

Addition Polymers - Types and Properties
Condensation Polymerization and Natural Polymers

By the end of the lesson, the learner should be able to:
Identify different addition polymers
- Draw structures from monomers
- Name common polymers
- Relate structure to properties

Study polystyrene, PTFE, perspex formation
- Practice identifying monomers from polymer structures
- Work through polymer calculation examples
- Properties analysis

Various polymer samples, structure identification exercises, calculation worksheets, Table 6.10
Nylon samples, rubber samples, condensation reaction diagrams, natural polymer examples

KLB Secondary Chemistry Form 4, Pages 195-197

ORGANIC CHEMISTRY II

Polymer Properties and Applications

By the end of the lesson, the learner should be able to:
Compare advantages and disadvantages of synthetic polymers
- State uses of different polymers
- Discuss environmental concerns
- Analyze polymer selection

Study Table 6.10 - polymer uses
- Advantages: strength, lightness, moldability
- Disadvantages: non-biodegradability, toxic gases
- Application analysis

Table 6.10, polymer application samples, environmental impact studies, product examples

KLB Secondary Chemistry Form 4, Pages 200-201

ORGANIC CHEMISTRY II
ACIDS, BASES AND SALTS

Comprehensive Problem Solving and Integration
Definition of Acids
Strength of Acids
Definition of Bases

By the end of the lesson, the learner should be able to:
Solve complex problems involving alkanols and acids
- Apply knowledge to practical situations
- Integrate polymer concepts
- Practice examination questions
- Compare strengths of acids using pH values
-Determine strengths of acids by comparing their electrical conductivity
-Classify acids as either strong or weak
-Explain complete and partial dissociation of acids

Worked examples on organic synthesis
- Problem-solving on isomers, reactions, polymers
- Integration of all unit concepts
- Practice examination-style questions
Class experiment: Test pH of 2M HCl and 2M ethanoic acid using universal indicator. Set up electrical conductivity apparatus with both acids. Record milliammeter readings. Compare results and explain in terms of hydrogen ion concentration. Discuss strong vs weak acid definitions.

Comprehensive problem sets, past examination papers, calculators, organic chemistry summary charts
Magnesium strips, zinc carbonate, 2M HCl, 2M ethanoic acid, 2M H₂SO₄, 2M ethanedioic acid, test tubes, test tube rack
2M HCl, 2M ethanoic acid, universal indicator, pH chart, electrical conductivity apparatus, milliammeter, carbon electrodes, beakers, wires
Calcium hydroxide, red litmus paper, phenolphthalein indicator, distilled water, test tubes, spatula, evaporating dish

KLB Secondary Chemistry Form 4, Pages 167-201
KLB Secondary Chemistry Form 4, Pages 3-5

ACIDS, BASES AND SALTS

Strength of Bases
Acid-Base Reactions
Effect of Solvent on Acids

By the end of the lesson, the learner should be able to:
- Compare strengths of bases using pH values
-Determine strengths of bases by comparing their electrical conductivity
-Classify bases as either strong or weak
-Explain complete and partial ionization of bases

Class experiment: Test pH of 2M NaOH and 2M ammonia solution using universal indicator. Test electrical conductivity of both solutions using same apparatus as acids. Compare deflections and pH values. Explain in terms of OH⁻ ion concentration and complete vs partial ionization.

2M NaOH, 2M ammonia solution, universal indicator, pH chart, electrical conductivity apparatus, milliammeter, carbon electrodes
Various acids and bases from previous lessons, indicators, beakers, measuring cylinders, stirring rods
HCl gas, distilled water, methylbenzene, magnesium ribbon, calcium carbonate, litmus paper, test tubes, gas absorption apparatus

KLB Secondary Chemistry Form 4, Pages 5-7

ACIDS, BASES AND SALTS

Effect of Solvent on Bases
Amphoteric Oxides and Hydroxides
Definition of Salts and Precipitation

By the end of the lesson, the learner should be able to:
- Investigate effect of polar and non-polar solvents on ammonia gas
-Compare ammonia behavior in water vs methylbenzene
-Explain formation of ammonium hydroxide
-Write equations for ammonia dissolution in water

Class experiment: Test dry ammonia with dry litmus. Dissolve ammonia in water and test with litmus. Dissolve ammonia in methylbenzene and test with litmus. Record observations in table. Write equation for NH₃ + H₂O reaction. Explain why only aqueous ammonia shows basic properties.

Dry ammonia gas, distilled water, methylbenzene, red litmus paper, test tubes, gas collection apparatus
Al₂O₃, ZnO, PbO, Zn(OH)₂, Al(OH)₃, Pb(OH)₂, 2M HNO₃, 2M NaOH, boiling tubes, heating source
Na₂CO₃ solution, salt solutions containing various metal ions, test tubes, droppers

KLB Secondary Chemistry Form 4, Pages 9-10

ACIDS, BASES AND SALTS

Solubility of Chlorides, Sulphates and Sulphites

By the end of the lesson, the learner should be able to:
- Find out cations that form insoluble chlorides, sulphates and sulphites
-Write ionic equations for formation of insoluble salts
-Distinguish between sulphate and sulphite precipitates
-Investigate effect of warming on precipitates

Class experiment: Add NaCl, Na₂SO₄, Na₂SO₃ to solutions of Pb²⁺, Ba²⁺, Mg²⁺, Ca²⁺, Zn²⁺, Cu²⁺, Fe²⁺, Fe³⁺, Al³⁺. Warm mixtures. Record observations in table. Test sulphite precipitates with dilute HCl. List soluble and insoluble salts.

2M NaCl, 2M Na₂SO₄, 2M Na₂SO₃, 0.1M salt solutions, dilute HCl, test tubes, heating source

KLB Secondary Chemistry Form 4, Pages 14-16

ACIDS, BASES AND SALTS

Complex Ions Formation
Solubility and Saturated Solutions
Effect of Temperature on Solubility

By the end of the lesson, the learner should be able to:
- Explain formation of complex ions
-Investigate reactions with excess sodium hydroxide and ammonia
-Identify metal ions that form complex ions
-Write equations for complex ion formation
- Define the term solubility
-Determine solubility of a given salt at room temperature
-Calculate mass of solute and solvent
-Express solubility in different units

Class experiment: Add NaOH dropwise then in excess to Mg²⁺, Ca²⁺, Zn²⁺, Al³⁺, Cu²⁺, Fe²⁺, Fe³⁺, Pb²⁺ solutions. Repeat with NH₃ solution. Record observations showing precipitate formation and dissolution. Write equations for complex ion formation: [Zn(OH)₄]²⁻, [Al(OH)₄]⁻, [Pb(OH)₄]²⁻, [Zn(NH₃)₄]²⁺, [Cu(NH₃)₄]²⁺.
Class experiment: Weigh evaporating dish and watch glass. Measure 20cm³ saturated KNO₃ solution. Record temperature. Evaporate to dryness carefully. Calculate masses of solute, solvent, and solution. Determine solubility per 100g water and in moles per litre. Discuss definition and significance.

2M NaOH, 2M NH₃ solution, 0.5M salt solutions, test tubes, droppers
Saturated KNO₃ solution, evaporating dish, watch glass, measuring cylinder, thermometer, balance, heating source
KClO₃, measuring cylinders, thermometer, burette, boiling tubes, heating source, graph paper

KLB Secondary Chemistry Form 4, Pages 15-16
KLB Secondary Chemistry Form 4, Pages 16-18

ACIDS, BASES AND SALTS

Solubility Curves and Applications

By the end of the lesson, the learner should be able to:
- Plot solubility curves for various salts
-Use solubility curves to determine mass of crystals formed
-Apply solubility curves to practical problems
-Compare solubility patterns of different salts

Using data from textbook, plot solubility curves for KNO₃, KClO₃, NaCl, CaSO₄. Calculate mass of crystals deposited when saturated solutions are cooled. Work through examples: KClO₃ cooled from 70°C to 30°C. Discuss applications in salt extraction and purification.

Graph paper, ruler, pencil, calculator, data tables from textbook

KLB Secondary Chemistry Form 4, Pages 20-21

ACIDS, BASES AND SALTS

Fractional Crystallization

By the end of the lesson, the learner should be able to:
- Define fractional crystallization
-Apply knowledge of solubility curves in separation of salts
-Calculate masses of salts that crystallize
-Explain separation of salt mixtures

Work through separation problems using solubility data for KNO₃ and KClO₃ mixtures. Calculate which salt crystallizes first when cooled from 50°C to 20°C. Plot combined solubility curves. Discuss applications in Lake Magadi and Ngomeni salt works. Solve practice problems.

Calculator, graph paper, data tables, worked examples from textbook

KLB Secondary Chemistry Form 4, Pages 21-22

ACIDS, BASES AND SALTS

Hardness of Water - Investigation
Types and Causes of Water Hardness

By the end of the lesson, the learner should be able to:
- Determine the effects of various salt solutions on soap
-Identify cations that cause hardness
-Distinguish between hard and soft water
-Investigate effect of boiling on water hardness

Class experiment: Test soap lathering with distilled water, tap water, rainwater, and solutions of MgCl₂, NaCl, Ca(NO₃)₂, CaHCO₃, NaHCO₃, ZnSO₄. Record volumes of soap needed. Boil some solutions and retest. Compare results and identify hardness-causing ions.

Soap solution, burette, various salt solutions, conical flasks, distilled water, tap water, rainwater, heating source
Student books, examples from previous experiment, chalkboard for equations

KLB Secondary Chemistry Form 4, Pages 22-24

ACIDS, BASES AND SALTS

Effects of Hard Water
Methods of Removing Hardness I

By the end of the lesson, the learner should be able to:
- State disadvantages of hard water
-State advantages of hard water
-Explain formation of scum and fur
-Discuss economic and health implications
- Explain removal of hardness by boiling
-Explain removal by distillation
-Write equations for these processes
-Compare effectiveness of different methods

Discussion based on practical experience: Soap wastage, scum formation on clothes, fur in kettles and pipes, pipe bursting in boilers. Advantages: calcium for bones, protection of lead pipes, use in brewing. Show examples of fur deposits. Calculate economic costs of hard water in households.
Demonstrate boiling method: Boil hard water samples from previous experiments and test with soap. Write equations for Ca(HCO₃)₂ and Mg(HCO₃)₂ decomposition. Discuss distillation method using apparatus setup. Compare costs and effectiveness. Explain why boiling only removes temporary hardness.

Samples of fur deposits, pictures of scaled pipes, calculator for cost analysis
Hard water samples, heating source, soap solution, distillation apparatus diagram

KLB Secondary Chemistry Form 4, Pages 24-25
KLB Secondary Chemistry Form 4, Pages 25-26

ACIDS, BASES AND SALTS
ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Methods of Removing Hardness II
Endothermic and Exothermic Reactions

By the end of the lesson, the learner should be able to:
- Explain removal using sodium carbonate
-Describe ion exchange method
-Explain removal using calcium hydroxide and ammonia
-Write equations for all processes

Demonstrate addition of Na₂CO₃ to hard water - observe precipitation. Explain ion exchange using resin (NaX) showing Ca²⁺ + 2NaX → CaX₂ + 2Na⁺. Discuss regeneration with brine. Write equations for Ca(OH)₂ and NH₃ methods. Compare all methods for effectiveness and cost.

Na₂CO₃ solution, hard water samples, ion exchange resin diagram, Ca(OH)₂, NH₃ solution
250ml plastic beakers, tissue paper, rubber bands, NH₄NO₃, NaOH pellets, distilled water, thermometers, spatulas, measuring cylinders

KLB Secondary Chemistry Form 4, Pages 25-26

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy Notation and Energy Content

By the end of the lesson, the learner should be able to:
- Define enthalpy and enthalpy change
-Use the symbol ΔH to represent enthalpy changes
-Calculate enthalpy changes using the formula ΔH = H(products) - H(reactants)
-Distinguish between positive and negative enthalpy changes

Q/A: Review previous experiment results. Introduce enthalpy symbol H and enthalpy change ΔH. Calculate enthalpy changes from previous experiments. Explain why endothermic reactions have positive ΔH and exothermic reactions have negative ΔH. Practice calculations with worked examples.

Student books, calculators, worked examples from textbook, chalkboard for calculations

KLB Secondary Chemistry Form 4, Pages 31-32

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Bond Breaking and Bond Formation

By the end of the lesson, the learner should be able to:
- Explain that energy changes are due to bond breaking and bond formation
-Describe bond breaking as endothermic and bond formation as exothermic
-Investigate energy changes during melting and boiling
-Plot heating curves for pure substances

Class experiment: Heat crushed ice while stirring with thermometer. Record temperature every minute until ice melts completely, then continue until water boils. Plot temperature-time graph. Explain constant temperature during melting and boiling in terms of bond breaking. Discuss latent heat of fusion and vaporization.

Crushed pure ice, 250ml glass beakers, thermometers, heating source, stopwatch, graph paper, stirring rods

KLB Secondary Chemistry Form 4, Pages 32-35

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Latent Heat of Fusion and Vaporization
Bond Energy Calculations
Determination of Enthalpy of Solution I

By the end of the lesson, the learner should be able to:
- Define latent heat of fusion and molar heat of fusion
-Define latent heat of vaporization and molar heat of vaporization
-Explain why temperature remains constant during phase changes
-Relate intermolecular forces to melting and boiling points
- Calculate energy changes in reactions using bond energies
-Apply the formula: Heat of reaction = Bond breaking energy + Bond formation energy
-Determine whether reactions are exothermic or endothermic
-Use bond energy data to solve problems

Discussion based on previous heating curve experiment. Explain energy used to overcome intermolecular forces during melting and boiling. Compare molar heats of fusion and vaporization for water and ethanol. Relate strength of intermolecular forces to magnitude of latent heats. Calculate energy required for phase changes.
Work through formation of HCl from H₂ and Cl₂ using bond energies. Calculate energy required to break H-H and Cl-Cl bonds. Calculate energy released when H-Cl bonds form. Apply formula: ΔH = Energy absorbed - Energy released. Practice with additional examples. Discuss why calculated values may differ from experimental values.

Data tables showing molar heats of fusion/vaporization, calculators, heating curves from previous lesson
Bond energy data tables, calculators, worked examples, practice problems
250ml plastic beakers, 2.0g samples of NH₄NO₃ and NaOH, distilled water, thermometers, measuring cylinders, analytical balance, calculators

KLB Secondary Chemistry Form 4, Pages 32-35
KLB Secondary Chemistry Form 4, Pages 35-36

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Thermochemical Equations

By the end of the lesson, the learner should be able to:
- Write thermochemical equations including enthalpy changes
-Define molar heat of solution
-Draw energy level diagrams for dissolution reactions
-Interpret thermochemical equations correctly

Using data from previous experiment, write thermochemical equations for NH₄NO₃ and NaOH dissolution. Show proper notation with state symbols and ΔH values. Draw corresponding energy level diagrams. Practice writing thermochemical equations for various reactions. Explain significance of molar quantities in equations.

Results from previous experiment, graph paper for energy level diagrams, practice examples

KLB Secondary Chemistry Form 4, Pages 38-39

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Solution of Concentrated Sulphuric Acid

By the end of the lesson, the learner should be able to:
- Determine heat of solution of concentrated sulphuric(VI) acid
-Apply safety precautions when handling concentrated acids
-Calculate enthalpy change considering density and purity
-Write thermochemical equation for the reaction

Teacher demonstration: Carefully add 2cm³ concentrated H₂SO₄ to 98cm³ distilled water in wrapped beaker (NEVER vice versa). Record temperature change. Calculate mass of acid using density (1.84 g/cm³) and purity (98%). Calculate molar heat of solution. Emphasize safety - always add acid to water.

Concentrated H₂SO₄, distilled water, 250ml plastic beaker, tissue paper, measuring cylinders, thermometer, safety equipment

KLB Secondary Chemistry Form 4, Pages 39-41

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Combustion
Enthalpy of Displacement

By the end of the lesson, the learner should be able to:
- Define molar heat of combustion
-Determine enthalpy of combustion of ethanol experimentally
-Explain why experimental values differ from theoretical values
-Calculate molar enthalpy of combustion from experimental data

Class experiment: Burn ethanol in small bottle with wick to heat 100cm³ water in glass beaker. Record initial and final masses of bottle+ethanol and temperature change. Calculate moles of ethanol burned and heat evolved. Determine molar enthalpy of combustion. Compare with theoretical value (-1368 kJ/mol). Discuss sources of error.

Ethanol, small bottles with wicks, 250ml glass beakers, tripod stands, wire gauze, thermometers, analytical balance, measuring cylinders
Zinc powder, 0.5M CuSO₄ solution, 250ml plastic beakers, tissue paper, thermometers, analytical balance, stirring rods

KLB Secondary Chemistry Form 4, Pages 41-44

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Neutralization
Standard Conditions and Standard Enthalpy Changes

By the end of the lesson, the learner should be able to:
- Define molar heat of neutralization
-Determine heat of neutralization of HCl with NaOH
-Compare neutralization enthalpies of strong and weak acids/bases
-Write ionic equations for neutralization reactions
- Identify standard conditions for measuring enthalpy changes
-Define standard enthalpy changes using ΔH° notation
-Explain importance of standard conditions
-Use subscripts to denote different types of enthalpy changes

Class experiment: Mix 50cm³ of 2M HCl with 50cm³ of 2M NaOH in wrapped beaker. Record temperature changes. Calculate molar heat of neutralization. Repeat with weak acid (ethanoic) and weak base (ammonia). Compare values. Write ionic equations. Explain why strong acid + strong base gives ~57.2 kJ/mol.
Q/A: Review previous enthalpy measurements. Introduce standard conditions: 25°C (298K) and 1 atmosphere pressure (101.325 kPa). Explain ΔH° notation and subscripts (ΔH°c for combustion, ΔH°f for formation, etc.). Discuss why standard conditions are necessary for comparison. Practice using correct notation.

2M HCl, 2M NaOH, 2M ethanoic acid, 2M ammonia solution, measuring cylinders, thermometers, 250ml plastic beakers, tissue paper
Student books, examples of standard enthalpy data, notation practice exercises

KLB Secondary Chemistry Form 4, Pages 47-49
KLB Secondary Chemistry Form 4, Pages 49

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Hess's Law - Introduction and Theory
Energy Cycle Diagrams

By the end of the lesson, the learner should be able to:
- State Hess's Law
-Explain the principle of energy conservation in chemical reactions
-Understand that enthalpy change is independent of reaction route
-Apply Hess's Law to simple examples

Introduce Hess's Law: "The energy change in converting reactants to products is the same regardless of the route by which the chemical change occurs." Use methane formation example to show two routes giving same overall energy change. Draw energy cycle diagrams. Explain law of conservation of energy application.

Energy cycle diagrams for methane formation, chalkboard illustrations, worked examples from textbook
Graph paper, energy cycle templates, combustion data tables, calculators

KLB Secondary Chemistry Form 4, Pages 49-52

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Hess's Law Calculations

By the end of the lesson, the learner should be able to:
- Solve complex problems using Hess's Law
-Apply energy cycles to multi-step reactions
-Calculate enthalpy of formation from combustion data
-Use thermochemical equations in Hess's Law problems

Work through detailed calculation for ethanol formation: 2C(s) + 3H₂(g) + ½O₂(g) → C₂H₅OH(l). Use combustion enthalpies of carbon (-393 kJ/mol), hydrogen (-286 kJ/mol), and ethanol (-1368 kJ/mol). Calculate ΔH°f(ethanol) = -278 kJ/mol. Practice with propane and other compounds.

Worked examples, combustion data, calculators, step-by-step calculation sheets

KLB Secondary Chemistry Form 4, Pages 54-56

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Lattice Energy and Hydration Energy

By the end of the lesson, the learner should be able to:
- Define lattice energy and hydration energy
-Explain relationship between heat of solution, lattice energy and hydration energy
-Draw energy cycles for dissolution of ionic compounds
-Calculate heat of solution using Born-Haber type cycles

Explain dissolution of NaCl: first lattice breaks (endothermic), then ions hydrate (exothermic). Define lattice energy as energy to form ionic solid from gaseous ions. Define hydration energy as energy when gaseous ions become hydrated. Draw energy cycle: ΔH(solution) = ΔH(lattice) + ΔH(hydration). Calculate for NaCl.

Energy cycle diagrams, lattice energy and hydration energy data tables, calculators

KLB Secondary Chemistry Form 4, Pages 54-56

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Factors Affecting Lattice and Hydration Energies
Definition and Types of Fuels
Heating Values of Fuels

By the end of the lesson, the learner should be able to:
- Explain factors affecting lattice energy
-Explain factors affecting hydration energy
-Use data tables to identify trends
-Calculate enthalpies of solution for various ionic compounds
- Define heating value of a fuel
-Calculate heating values from molar enthalpies of combustion
-Compare heating values of different fuels
-Explain units of heating value (kJ/g)

Analyze data tables showing lattice energies (Table 2.7) and hydration energies (Table 2.6). Identify trends: smaller ions and higher charges give larger lattice energies and hydration energies. Calculate heat of solution for MgCl₂ using: ΔH(solution) = +2489 + (-1891 + 2×(-384)) = -170 kJ/mol. Practice with other compounds.
Calculate heating value of ethanol: ΔH°c = -1360 kJ/mol, Molar mass = 46 g/mol, Heating value = 1360/46 = 30 kJ/g. Compare heating values from Table 2.8: methane (55 kJ/g), fuel oil (45 kJ/g), charcoal (33 kJ/g), wood (17 kJ/g). Discuss significance of these values for fuel selection.

Data tables from textbook, calculators, trend analysis exercises
Examples of different fuels, classification charts, pictures of fuel types
Heating value data table, calculators, fuel comparison charts

KLB Secondary Chemistry Form 4, Pages 54-56
KLB Secondary Chemistry Form 4, Pages 56-57

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Factors in Fuel Selection

By the end of the lesson, the learner should be able to:
- State factors that influence choice of fuel
-Explain why different fuels are chosen for different purposes
-Compare advantages and disadvantages of various fuels
-Apply selection criteria to real situations

Discuss seven factors: heating value, ease of combustion, availability, transportation, storage, environmental effects, cost. Compare wood/charcoal for domestic use vs methylhydrazine for rockets. Analyze why each is suitable for its purpose. Students suggest best fuels for cooking, heating, transport in their area.

Fuel comparison tables, local fuel availability data, cost analysis sheets

KLB Secondary Chemistry Form 4, Pages 57

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Environmental Effects of Fuels
Fuel Safety and Precautions

By the end of the lesson, the learner should be able to:
- Identify environmental effects of burning fuels
-Explain formation and effects of acid rain
-Describe contribution to global warming
-State measures to reduce pollution from fuels

Discuss pollutants from fossil fuels: SO₂, SO₃, CO, NO₂ causing acid rain. Effects: damage to buildings, corrosion, acidification of lakes, soil leaching. CO₂ and hydrocarbons cause global warming leading to ice melting, climate change. Pollution reduction measures: catalytic converters, unleaded petrol, zero emission vehicles, alternative fuels.

Pictures of environmental damage, pollution data, examples of clean technology
Safety guideline charts, examples of fuel accidents, local safety case studies

KLB Secondary Chemistry Form 4, Pages 57-58

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Endothermic and Exothermic Reactions

By the end of the lesson, the learner should be able to:
- Define endothermic and exothermic reactions using the ΔH notation
-Investigate what happens when ammonium nitrate and sodium hydroxide are separately dissolved in water
-Define enthalpy and enthalpy change
-Calculate enthalpy changes using ΔH = H(products) - H(reactants)

Class experiment: Dissolve NH₄NO₃ and NaOH separately in water, record temperature changes in Table 2.1. Explain heat absorption vs evolution. Introduce enthalpy (H) and enthalpy change (ΔH). Calculate enthalpy changes from experimental data. Draw energy level diagrams showing relative energies.

250ml plastic beakers, tissue paper, NH₄NO₃, NaOH pellets, distilled water, thermometers, calculators

KLB Secondary Chemistry Form 4, Pages 29-32

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Bond Breaking, Formation and Phase Changes
Determination of Enthalpy of Solution
Enthalpy of Solution of H₂SO₄ and Safety

By the end of the lesson, the learner should be able to:
- Explain that energy changes are due to bond breaking and bond formation
-Investigate energy changes when solids and liquids are heated
-Define latent heat of fusion and vaporization
-Calculate energy changes using bond energies
- Carry out experiments to determine enthalpy changes of solution
-Calculate enthalpy change using ΔH = mcΔT
-Write correct thermochemical equations
-Define molar heat of solution

Class experiment: Heat ice to melting then boiling, record temperature every minute. Plot heating curve. Explain constant temperature periods. Define latent heat of fusion/vaporization. Calculate energy changes in H₂ + Cl₂ → 2HCl using bond energies. Apply formula: ΔH = Energy absorbed - Energy released.
Class experiment: Dissolve exactly 2.0g NH₄NO₃ and 2.0g NaOH separately in 100ml water. Record temperature changes. Calculate enthalpy changes using ΔH = mcΔT. Calculate moles and molar heat of solution. Write thermochemical equations: NH₄NO₃(s) + aq → NH₄NO₃(aq) ΔH = +25.2 kJ mol⁻¹.

Ice, glass beakers, thermometers, heating source, graph paper, bond energy data tables
2.0g samples of NH₄NO₃ and NaOH, plastic beakers, thermometers, analytical balance, calculators
Concentrated H₂SO₄, distilled water, plastic beaker, tissue paper, thermometer, safety equipment

KLB Secondary Chemistry Form 4, Pages 32-36
KLB Secondary Chemistry Form 4, Pages 36-39

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Combustion

By the end of the lesson, the learner should be able to:
- Carry out experiments to determine enthalpy of combustion of ethanol
-Define molar heat of combustion
-Calculate molar enthalpy of combustion from experimental data
-Explain why actual heats are lower than theoretical values

Class experiment: Burn ethanol to heat 100cm³ water. Record mass of ethanol burned and temperature change. Calculate moles of ethanol and heat evolved using ΔH = mcΔT. Determine molar enthalpy of combustion. Compare with theoretical (-1368 kJ/mol). Discuss heat losses to surroundings.

Ethanol, bottles with wicks, glass beakers, tripod stands, thermometers, analytical balance

KLB Secondary Chemistry Form 4, Pages 41-44

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Displacement

By the end of the lesson, the learner should be able to:
- Investigate enthalpy change when zinc reacts with copper(II) sulphate
-Define molar heat of displacement
-Calculate molar heat of displacement from experimental data
-Explain relationship between reactivity series and heat evolved

Class experiment: Add 4.0g zinc powder to 100cm³ of 0.5M CuSO₄. Record temperature change and observations (blue color fades, brown solid). Calculate moles and molar heat of displacement. Write ionic equation: Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s). Explain why excess zinc is used.

Zinc powder, 0.5M CuSO₄ solution, plastic beakers, thermometers, analytical balance

KLB Secondary Chemistry Form 4, Pages 44-47

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Neutralization
Standard Conditions and Standard Enthalpy Changes

By the end of the lesson, the learner should be able to:
- Determine heat of neutralization of HCl with NaOH
-Define molar heat of neutralization
-Compare strong acid/base with weak acid/base combinations
-Write ionic equations including enthalpy changes

Class experiment: Mix 50cm³ of 2M HCl with 50cm³ of 2M NaOH. Record temperatures and calculate molar heat of neutralization. Repeat with weak acid/base. Compare values: strong + strong ≈ 57.2 kJ/mol, weak combinations give lower values. Write H⁺(aq) + OH⁻(aq) → H₂O(l) ΔH = -57.2 kJ mol⁻¹.

2M HCl, 2M NaOH, 2M ethanoic acid, 2M ammonia solution, measuring cylinders, thermometers, plastic beakers
Student books, standard enthalpy data examples, notation practice exercises

KLB Secondary Chemistry Form 4, Pages 47-49

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Hess's Law - Theory and Energy Cycles
Hess's Law Calculations

By the end of the lesson, the learner should be able to:
- State Hess's Law
-Explain that enthalpy change is independent of reaction route
-Draw energy cycle diagrams
-Apply Hess's Law to determine enthalpy of formation
- Carry out calculations using Hess's Law
-Draw energy level diagrams
-Calculate enthalpy of formation from combustion data
-Solve worked examples using energy cycles

Introduce Hess's Law: "Energy change in converting reactants to products is same regardless of route." Use methane formation showing Route 1 (direct combustion) vs Route 2 (formation then combustion). Draw energy cycle. Calculate ΔH°f(CH₄) = -965 + (-890) - (-75) = -75 kJ/mol. Practice with CO formation example.
Work through ethanol formation: 2C(s) + 3H₂(g) + ½O₂(g) → C₂H₅OH(l). Draw energy cycle and level diagrams. Apply: ΔH°f(ethanol) = 2×ΔH°c(C) + 3×ΔH°c(H₂) - ΔH°c(ethanol) = 2×(-393) + 3×(-286) - (-1368) = -278 kJ/mol. Practice additional calculations from revision exercises.

Energy cycle diagrams for methane and CO formation, combustion data, calculators
Worked examples, combustion data tables, graph paper for diagrams, calculators

KLB Secondary Chemistry Form 4, Pages 49-52
KLB Secondary Chemistry Form 4, Pages 52-56

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Lattice Energy and Hydration Energy
Definition and Types of Fuels

By the end of the lesson, the learner should be able to:
- Explain relationship between heat of solution, hydration and lattice energy
-Define lattice energy and hydration energy
-Draw energy cycles for dissolving ionic compounds
-Calculate heat of solution using energy cycles

Explain NaCl dissolution: lattice breaks (endothermic) then ions hydrate (exothermic). Define lattice energy as energy when ionic compound forms from gaseous ions. Define hydration energy as energy when gaseous ions become hydrated. Draw energy cycle: ΔH(solution) = ΔH(lattice) + ΔH(hydration). Calculate for NaCl: +781 + (-774) = +7 kJ/mol.

Energy cycle diagrams, hydration diagram (Fig 2.17), Tables 2.6 and 2.7 with lattice/hydration energies
Examples of local fuels, Table 2.8 showing heating values, calculators

KLB Secondary Chemistry Form 4, Pages 54-56

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Fuel Selection Factors
Environmental Effects and Safety

By the end of the lesson, the learner should be able to:
- State and explain factors that influence choice of a fuel
-Compare suitability of fuels for different purposes
-Explain fuel selection for domestic use vs specialized applications
-Apply selection criteria to local situations

Discuss seven factors: heating value, ease of combustion, availability, transportation, storage, environmental effects, cost. Compare wood/charcoal for domestic use (cheap, available, safe, slow burning) vs methylhydrazine for rockets (rapid burning, high heat 4740 kJ/mol, easy ignition). Students analyze best fuels for their local area.

Fuel comparison tables, local fuel cost data, examples of specialized fuel applications
Pictures of environmental damage, pollution reduction examples, safety guideline charts

KLB Secondary Chemistry Form 4, Pages 57