SULPHUR AND ITS COMPOUNDS

Extraction of Sulphur
Allotropes of Sulphur
Physical Properties of Sulphur - Solubility

By the end of the lesson, the learner should be able to:
Define sulphur and state its position in the periodic table. Describe the occurrence of sulphur in nature. Explain the Frasch process for extraction of sulphur. Evaluate the effectiveness of the Frasch process.
Define allotropy and allotropes. Prepare rhombic sulphur in the laboratory. Prepare monoclinic sulphur in the laboratory. Compare the properties of rhombic and monoclinic sulphur.

Q/A: Review group VI elements and electron configuration of sulphur. Teacher demonstration: Using diagrams to explain the Frasch process setup. Discussion: Why ordinary mining is impossible for sulphur deposits. Group work: Students draw and label the Frasch process diagram.
Practical work: Experiment 1(a) - Preparation of rhombic sulphur using carbon(IV) sulphide. Practical work: Experiment 1(b) - Preparation of monoclinic sulphur by heating and cooling. Observation: Using hand lens to examine crystal shapes. Discussion: Compare crystal structures and transition temperature.

Charts showing periodic table, Diagram of Frasch process, Samples of sulphur compounds (pyrites, gypsum)
Powdered sulphur, Carbon(IV) sulphide, Evaporating dish, Glass rod, Hand lens, Boiling tubes, Filter paper, Beakers
Powdered sulphur, Water, Benzene, Methylbenzene, Carbon(IV) sulphide, Test tubes, Charts showing molecular structure

KLB Secondary Chemistry Form 4, Pages 160-161
KLB Secondary Chemistry Form 4, Pages 161-163

SULPHUR AND ITS COMPOUNDS

Physical Properties of Sulphur - Effect of Heat
Chemical Properties of Sulphur - Reactions with Elements
Chemical Properties of Sulphur - Reactions with Acids

By the end of the lesson, the learner should be able to:
Investigate the effect of heat on sulphur. Describe changes in color and viscosity of molten sulphur. Explain the molecular changes occurring during heating. Identify "flowers of sulphur".

Practical work: Experiment 2(b) - Heating sulphur and observing changes. Observation: Color changes from yellow to amber to reddish-brown to black. Testing viscosity by inverting test tube. Demonstration: Sublimation of sulphur vapour. Discussion: Breaking of S8 rings to form long chains.

Powdered sulphur, Test tubes, Bunsen burner, Cold surface for condensation, Thermometer, Safety equipment
Sulphur, Iron powder, Copper powder, Oxygen gas jar, Deflagrating spoon, Moist litmus papers, Test tubes, Bunsen burner
Sulphur powder, Concentrated HNO3, Concentrated H2SO4, Concentrated HCl, Barium chloride solution, Test tubes, Fume cupboard access

KLB Secondary Chemistry Form 4, Pages 164-165

SULPHUR AND ITS COMPOUNDS

Uses of Sulphur and Introduction to Oxides
Preparation of Sulphur(IV) Oxide
Physical and Chemical Properties of Sulphur(IV) Oxide

By the end of the lesson, the learner should be able to:
List the uses of sulphur in industry and agriculture. Identify the two main oxides of sulphur. Compare sulphur(IV) oxide and sulphur(VI) oxide. Plan laboratory preparation methods for sulphur oxides.

Discussion: Industrial uses - sulphuric acid manufacture, fungicide, vulcanization of rubber, bleaching agents, dyes and fireworks. Q/A: Review oxidation states of sulphur in compounds. Introduction: SO2 and SO3 as important compounds. Preparation planning: Methods for laboratory preparation of SO

Charts showing uses of sulphur, Samples of vulcanized rubber, Fungicides, Industrial photographs, Textbook diagrams
Sodium sulphite, Dilute HCl, Round-bottomed flask, Delivery tubes, Gas jars, Concentrated H2SO4 for drying, Acidified potassium chromate(VI) paper
SO2 gas from previous preparation, Litmus papers, Universal indicator, 0.1M NaOH solution, Water, Test tubes, Safety equipment

KLB Secondary Chemistry Form 4, Pages 168-170

SULPHUR AND ITS COMPOUNDS

Bleaching Action of Sulphur(IV) Oxide

By the end of the lesson, the learner should be able to:
Investigate the bleaching properties of SO Compare SO2 bleaching with chlorine bleaching. Explain the mechanism of SO2 bleaching. Relate bleaching to paper manufacturing.

Practical work: Experiment 6 - Placing colored flower petals in SO2 gas. Observation: Temporary bleaching effect. Discussion: SO2 + H2O → H2SO3, reduction of organic dyes. Comparison: Permanent vs temporary bleaching. Application: Paper industry bleaching processes.

Colored flower petals (red/blue), SO2 gas jars, Hand lens for observation, Charts comparing bleaching agents

KLB Secondary Chemistry Form 4, Pages 173

SULPHUR AND ITS COMPOUNDS

Reducing Action of Sulphur(IV) Oxide
Oxidising Action of Sulphur(IV) Oxide

By the end of the lesson, the learner should be able to:
Investigate SO2 as a reducing agent. Test reactions with various oxidizing agents. Write ionic equations for redox reactions. Identify color changes in redox reactions.
Investigate SO2 as an oxidizing agent. Demonstrate reaction with stronger reducing agents. Explain the dual nature of SO Write equations for oxidation reactions by SO

Practical work: Experiment 7 - Testing SO2 with acidified potassium dichromate(VI), potassium manganate(VII), bromine water, iron(III) chloride. Recording observations in Table 6. Color changes: Orange to green, purple to colorless, brown to colorless, yellow to pale green. Writing half-equations and overall equations.
Practical work: Experiment 8 - Lowering burning magnesium into SO2 gas. Observation: Continued burning, white fumes of MgO, yellow specks of sulphur. Reaction with hydrogen sulphide gas (demonstration). Discussion: SO2 decomposition providing oxygen. Writing equations: 2Mg + SO2 → 2MgO + S.

SO2 gas, Acidified K2Cr2O7, Acidified KMnO4, Bromine water, Iron(III) chloride solution, Concentrated HNO3, Test tubes
SO2 gas jars, Magnesium ribbon, Deflagrating spoon, Hydrogen sulphide gas, Water droppers, Safety equipment

KLB Secondary Chemistry Form 4, Pages 173-176
KLB Secondary Chemistry Form 4, Pages 176-177

SULPHUR AND ITS COMPOUNDS

Test for Sulphate and Sulphite Ions & Uses of SO2
Large-scale Manufacture of Sulphuric(VI) Acid - Contact Process

By the end of the lesson, the learner should be able to:
Carry out confirmatory tests for sulphate and sulphite ions. Distinguish between sulphate and sulphite using chemical tests. List the uses of sulphur(IV) oxide. Explain the applications in industry.

Practical work: Experiment 9 - Testing sodium sulphate and sodium sulphite with barium chloride. Adding dilute HCl to precipitates. Recording observations in Table 8. Discussion: BaSO4 insoluble in acid, BaSO3 dissolves. Uses: Raw material for H2SO4, bleaching wood pulp, fumigant, preservative.

Sodium sulphate solution, Sodium sulphite solution, Barium chloride solution, Dilute HCl, Test tubes, Charts showing industrial uses
Flow chart diagrams, Charts showing industrial plant, Samples of catalyst (V2O5), Photographs of Thika chemical plant, Calculator for percentage calculations

KLB Secondary Chemistry Form 4, Pages 178-179

SULPHUR AND ITS COMPOUNDS

Properties of Concentrated Sulphuric(VI) Acid - Dehydrating Properties

By the end of the lesson, the learner should be able to:
Investigate the dehydrating properties of concentrated H2SO Demonstrate removal of water from hydrated salts. Show dehydration of organic compounds. Explain the hygroscopic nature of the acid.

Practical work: Experiment 10 - Adding concentrated H2SO4 to copper(II) sulphate crystals, sucrose crystals, ethanol. Observations: Blue to white crystals, charring of sugar, formation of ethene. Safety: Proper dilution technique - acid to water. Testing evolved gases. Discussion: Chemical vs physical dehydration.

Concentrated H2SO4, Copper(II) sulphate crystals, Sucrose, Ethanol, KMnO4 solution, Test tubes, Beakers, Safety equipment, Fume cupboard

KLB Secondary Chemistry Form 4, Pages 181-183

SULPHUR AND ITS COMPOUNDS

Properties of Concentrated Sulphuric(VI) Acid - Oxidizing Properties

By the end of the lesson, the learner should be able to:
Investigate the oxidizing properties of concentrated H2SO Test reactions with metals and non-metals. Identify the products of oxidation reactions. Write balanced equations for redox reactions.

Practical work: Experiment 10 (continued) - Reactions with copper foil, zinc granules, charcoal. Testing evolved gases with acidified K2Cr2O7 paper, lime water. Observations: SO2 evolution, color changes. Discussion: H2SO4 → SO2 + H2O + [O]. Writing half-equations and overall equations.

Copper foil, Zinc granules, Charcoal powder, Concentrated H2SO4, Acidified K2Cr2O7 paper, Lime water, Test tubes, Bunsen burner

KLB Secondary Chemistry Form 4, Pages 183-184

SULPHUR AND ITS COMPOUNDS

Properties of Concentrated Sulphuric(VI) Acid - Displacement Reactions
Reactions of Dilute Sulphuric(VI) Acid - With Metals

By the end of the lesson, the learner should be able to:
Investigate acid displacement reactions. Demonstrate formation of volatile acids. Test the evolved gases for identification. Write equations for displacement reactions.

Practical work: Experiment 10 (continued) - Reactions with potassium nitrate and sodium chloride. Testing evolved gases with moist blue litmus, concentrated ammonia. Observations: Brown fumes (NO2), white fumes (HCl). Discussion: Less volatile acid displacing more volatile acids. Industrial applications.

Potassium nitrate crystals, Sodium chloride crystals, Concentrated H2SO4, Moist blue litmus paper, Concentrated ammonia, Test tubes, Bunsen burner
Magnesium ribbon, Zinc granules, Copper turnings, Dilute H2SO4, Test tubes, Burning splints, Reactivity series chart

KLB Secondary Chemistry Form 4, Pages 184

SULPHUR AND ITS COMPOUNDS

Reactions of Dilute Sulphuric(VI) Acid - With Carbonates
Reactions of Dilute Sulphuric(VI) Acid - With Oxides and Hydroxides

By the end of the lesson, the learner should be able to:
Investigate reactions of dilute H2SO4 with carbonates. Test for carbon dioxide evolution. Explain why some reactions stop prematurely. Compare reactions of different metal carbonates.
Investigate reactions of dilute H2SO4 with metal oxides and hydroxides. Identify neutralization reactions. Explain formation of insoluble sulphates. Write equations for acid-base reactions.

Practical work: Experiment 12 - Reactions with sodium carbonate, zinc carbonate, calcium carbonate, copper(II) carbonate. Testing evolved gas with lime water. Recording observations in Table 1 Discussion: Formation of insoluble calcium sulphate coating. Effervescence and CO2 identification.
Practical work: Experiment 13 - Reactions with magnesium oxide, zinc oxide, copper(II) oxide, lead(II) oxide, sodium hydroxide. Recording observations in Table 1 Discussion: Salt and water formation, immediate stopping with lead(II) oxide due to insoluble PbSO Acid-base neutralization concept.

Sodium carbonate, Zinc carbonate, Calcium carbonate, Copper(II) carbonate, Dilute H2SO4, Lime water, Test tubes
Metal oxides (MgO, ZnO, CuO, PbO), NaOH solution, 2M H2SO4, Test tubes, Bunsen burner for warming

KLB Secondary Chemistry Form 4, Pages 185-186
KLB Secondary Chemistry Form 4, Pages 186-187

SULPHUR AND ITS COMPOUNDS

Hydrogen Sulphide - Preparation and Physical Properties
Chemical Properties of Hydrogen Sulphide

By the end of the lesson, the learner should be able to:
Describe laboratory preparation of hydrogen sulphide. Set up apparatus for H2S preparation. State the physical properties of H2S. Explain the toxicity and safety precautions.

Demonstration: Figure 13 apparatus setup for H2S preparation. Reaction: FeS + 2HCl → FeCl2 + H2S. Collection over warm water due to solubility. Drying: Using anhydrous CaCl2 (not H2SO4). Properties: Colorless, rotten egg smell, poisonous, denser than air. Safety precautions in handling.

Iron(II) sulphide, Dilute HCl, Apparatus for gas generation, Anhydrous CaCl2, Gas jars, Safety equipment, Fume cupboard
H2S gas, Bromine water, Iron(III) chloride, KMnO4, K2Cr2O7, Metal salt solutions, Test tubes, Droppers

KLB Secondary Chemistry Form 4, Pages 187-188

SULPHUR AND ITS COMPOUNDS

Pollution Effects and Summary

By the end of the lesson, the learner should be able to:
Explain environmental pollution by sulphur compounds. Describe formation and effects of acid rain. Suggest methods to reduce sulphur pollution. Summarize key concepts of sulphur chemistry.

Discussion: Sources of SO2 pollution - burning fossil fuels, metal extraction, H2SO4 manufacture. Formation of acid rain: SO2 + H2O → H2SO3 → H2SO Effects: Plant damage, aquatic life destruction, building corrosion, soil acidification. Control measures: Scrubbing with Ca(OH)2, catalytic converters. Revision: Key reactions, properties, uses.

Charts showing pollution effects, Photographs of acid rain damage, Environmental data, Summary charts of reactions, Industrial pollution control diagrams

KLB Secondary Chemistry Form 4, Pages 190-194

NITROGEN AND ITS COMPOUNDS

Chemical Properties of Ammonia - Reactions with Acids and Combustion

By the end of the lesson, the learner should be able to:
Test neutralization reactions with acids
Investigate combustion of ammonia
Examine catalytic oxidation with platinum
Study reducing properties with metal oxides

Experiments: (a) Neutralize H₂SO₄, HCl, HNO₃ with aqueous ammonia using indicators. (b) Attempt combustion in air and oxygen. (c) Catalytic oxidation with heated platinum wire. (d) Reduction of CuO by ammonia. Record all observations.

Various dilute acids, Methyl orange, Oxygen supply, Platinum wire, Copper(II) oxide, Combustion apparatus, U-tube for collection

KLB Secondary Chemistry Form 3, Pages 138-140

NITROGEN AND ITS COMPOUNDS

Industrial Manufacture of Ammonia - The Haber Process
Uses of Ammonia and Introduction to Nitrogenous Fertilizers
Nitrogenous Fertilizers - Types and Calculations

By the end of the lesson, the learner should be able to:
Describe raw materials and their sources
Explain optimum conditions for ammonia synthesis
Draw flow diagram of Haber process
Explain economic considerations and catalyst use
List major uses of ammonia
Explain importance as fertilizer
Calculate nitrogen percentages in fertilizers
Compare different nitrogenous fertilizers

Teacher exposition: N₂ from air, H₂ from natural gas/cracking. Process conditions: 500°C, 200 atm, iron catalyst. Flow diagram study: Purification, compression, catalytic chamber, separation, recycling. Economic factors: Compromise between yield and rate.
Discussion: Uses - fertilizer, refrigerant, cleaning agent, hydrazine production. Introduction to fertilizers: Ammonium sulfate, ammonium nitrate, ammonium phosphate, urea, CAN. Calculations: Percentage nitrogen content in each fertilizer type.

Haber process flow charts, Industrial diagrams, Catalyst samples, Economic analysis sheets
Fertilizer samples, Percentage calculation worksheets, Use application charts, Calculator
Various fertilizer formulas, Scientific calculators, Laboratory preparation materials, Environmental impact data

KLB Secondary Chemistry Form 3, Pages 140-141
KLB Secondary Chemistry Form 3, Pages 141-144

NITROGEN AND ITS COMPOUNDS

Laboratory Preparation of Nitric(V) Acid

By the end of the lesson, the learner should be able to:
Prepare nitric acid from nitrate and concentrated sulfuric acid
Set up all-glass apparatus safely
Explain brown fumes and yellow color
Purify nitric acid by air bubbling

Experiment: Heat mixture of KNO₃ and concentrated H₂SO₄ in all-glass apparatus. Collect yellow nitric acid. Explain brown fumes (NO₂) and yellow color. Bubble air through to remove dissolved NO₂. Safety: Gentle heating, fume cupboard.

Potassium nitrate, Concentrated sulfuric acid, All-glass apparatus, Condenser, Retort stand, Safety equipment

KLB Secondary Chemistry Form 3, Pages 144-145

NITROGEN AND ITS COMPOUNDS

Industrial Manufacture of Nitric(V) Acid

By the end of the lesson, the learner should be able to:
Describe catalytic oxidation process
Explain raw materials and conditions
Draw flow diagram of industrial process
Calculate theoretical yields and efficiency

Teacher exposition: Ostwald process - NH₃ oxidation with Pt-Rh catalyst at 900°C. Flow diagram: Oxidation chamber, cooling, absorption tower. Equations: NH₃ → NO → NO₂ → HNO₃. Economic factors: Catalyst cost, heat recovery.

Industrial process flow charts, Catalyst samples, Process condition charts, Efficiency calculation sheets

KLB Secondary Chemistry Form 3, Pages 145-147

NITROGEN AND ITS COMPOUNDS

Reactions of Dilute Nitric(V) Acid with Metals
Reactions of Dilute Nitric(V) Acid with Carbonates and Hydroxides

By the end of the lesson, the learner should be able to:
Test reactions with various metals
Explain absence of hydrogen gas production
Observe formation of nitrogen oxides
Write equations for metal-acid reactions

Experiment: Add dilute HNO₃ to Mg, Zn, Cu. Test gases produced with burning splint. Observe that no H₂ is produced (except with Mg in very dilute acid). Explain oxidation of any H₂ formed to water. Record observations and write equations.

Various metals (Mg, Zn, Cu), Dilute nitric acid, Test tubes, Gas testing apparatus, Burning splints
Various carbonates and hydroxides, Dilute nitric acid, Lime water, Universal indicator, Test tubes

KLB Secondary Chemistry Form 3, Pages 147-150

NITROGEN AND ITS COMPOUNDS

Reactions of Concentrated Nitric(V) Acid - Oxidizing Properties
Uses of Nitric(V) Acid and Introduction to Nitrates

By the end of the lesson, the learner should be able to:
Demonstrate strong oxidizing properties
Test reactions with FeSO₄, sulfur, and copper
Observe formation of nitrogen dioxide
Explain electron transfer in oxidation
List major industrial uses of nitric acid
Explain importance in fertilizer manufacture
Describe use in explosives and dyes
Introduce nitrate salts and their preparation

Experiments: (a) Add concentrated HNO₃ to acidified FeSO₄ - observe color change. (b) Add to sulfur - observe reaction. (c) Add to copper turnings - observe vigorous reaction and brown fumes. Explain oxidizing power and reduction to NO₂.
Discussion: Uses - fertilizer production (NH₄NO₃), explosives (TNT), dyes, drugs, metal purification, etching. Introduction to nitrates as salts of nitric acid. Methods of preparation: acid + base, acid + carbonate, acid + metal. Examples of common nitrates.

Concentrated nitric acid, Iron(II) sulfate, Sulfur powder, Copper turnings, Test tubes, Fume cupboard access
Industrial use charts, Nitrate salt samples, Preparation method diagrams, Safety data sheets

KLB Secondary Chemistry Form 3, Pages 150-151
KLB Secondary Chemistry Form 3, Pages 151

NITROGEN AND ITS COMPOUNDS

Action of Heat on Nitrates - Decomposition Patterns
Test for Nitrates - Brown Ring Test

By the end of the lesson, the learner should be able to:
Test thermal decomposition of different nitrates
Classify decomposition patterns based on metal reactivity
Identify products formed on heating
Write equations for decomposition reactions

Experiment: Heat KNO₃, NaNO₃, Zn(NO₃)₂, Cu(NO₃)₂, NH₄NO₃ separately. Test gases with glowing splint. Observe residues. Classification: Group I nitrates → nitrite + O₂; Group II → oxide + NO₂ + O₂; NH₄NO₃ → N₂O + H₂O.

Various nitrate salts, Test tubes, Bunsen burner, Gas collection apparatus, Glowing splints, Observation recording sheets
Sodium nitrate, Fresh FeSO₄ solution, Concentrated H₂SO₄, Copper turnings, Test tubes, Unknown nitrate samples

KLB Secondary Chemistry Form 3, Pages 151-153

NITROGEN AND ITS COMPOUNDS

Environmental Pollution by Nitrogen Compounds

By the end of the lesson, the learner should be able to:
Explain sources of nitrogen pollution
Describe formation of acid rain
Discuss effects on environment and health
Evaluate pollution control measures

Teacher exposition: NOₓ from vehicles, HNO₃ formation in atmosphere, acid rain effects. Discussion: Chlorosis in plants, building corrosion, soil leaching, smog formation, health effects. Control measures: Catalytic converters, emission controls, proper fertilizer use.

Environmental pollution charts, Acid rain effect photos, Vehicle emission diagrams, Control measure illustrations

KLB Secondary Chemistry Form 3, Pages 154-157

NITROGEN AND ITS COMPOUNDS

Pollution Control and Environmental Solutions

By the end of the lesson, the learner should be able to:
Analyze methods to reduce nitrogen pollution
Design pollution control strategies
Evaluate effectiveness of current measures
Propose new solutions for environmental protection

Discussion and analysis: Catalytic converters in vehicles, sewage treatment, lime addition to soils/lakes, proper fertilizer application, industrial gas recycling. Group activity: Design pollution control strategy for local area. Evaluation of current measures.

Case studies, Pollution control technology information, Group activity worksheets, Local environmental data

KLB Secondary Chemistry Form 3, Pages 154-157

NITROGEN AND ITS COMPOUNDS

Comprehensive Problem Solving - Nitrogen Chemistry
Laboratory Practical Assessment - Nitrogen Compounds
Industrial Applications and Economic Importance

By the end of the lesson, the learner should be able to:
Solve complex problems involving nitrogen compounds
Apply knowledge to industrial processes
Calculate yields and percentages in reactions
Analyze experimental data and results
Demonstrate practical skills in nitrogen chemistry
Perform qualitative analysis of nitrogen compounds
Apply safety procedures correctly
Interpret experimental observations accurately

Problem-solving session: Mixed calculations involving nitrogen preparation, ammonia synthesis, nitric acid concentration, fertilizer analysis. Industrial application problems. Data analysis from experiments. Integration of all nitrogen chemistry concepts.
Practical examination: Identify unknown nitrogen compounds using chemical tests. Prepare specified nitrogen compounds. Demonstrate proper laboratory techniques. Safety assessment. Written report on observations and conclusions.

Scientific calculators, Comprehensive problem sets, Industrial data sheets, Experimental result tables
Unknown nitrogen compounds, All laboratory chemicals and apparatus used in chapter, Safety equipment, Assessment rubrics
Economic data sheets, Industry case studies, Agricultural statistics, Cost-benefit analysis templates

KLB Secondary Chemistry Form 3, Pages 119-157

NITROGEN AND ITS COMPOUNDS
GAS LAWS

Chapter Review and Integration
Boyle's Law - Introduction and Experimental Investigation

By the end of the lesson, the learner should be able to:
Synthesize all nitrogen chemistry concepts
Compare preparation methods for nitrogen compounds
Relate structure to properties and reactivity
Connect laboratory and industrial processes

Comprehensive review: Concept mapping of all nitrogen compounds and their relationships. Comparison tables: Preparation methods, properties, uses. Flow chart: Nitrogen cycle in industry and environment. Integration exercises connecting all topics.

Concept mapping materials, Comparison charts, Flow diagram templates, Integration worksheets
Bicycle pump, Syringes, Gas jars, Chart showing volume-pressure relationship

KLB Secondary Chemistry Form 3, Pages 119-157

GAS LAWS

Boyle's Law - Mathematical Expression and Graphical Representation
Boyle's Law - Numerical Problems and Applications

By the end of the lesson, the learner should be able to:
Express Boyle's law mathematically
Apply the equation PV = constant
Plot and interpret pressure vs volume graphs
Plot pressure vs 1/volume graphs

Q/A: Recall previous lesson observations. Teacher exposition: Derive P₁V₁ = P₂V₂ equation from experimental data. Students plot graphs of pressure vs volume and pressure vs 1/volume. Analyze graph shapes and interpret mathematical relationship.

Graph papers, Scientific calculators, Chart showing mathematical expressions
Scientific calculators, Worked example charts, Unit conversion tables

KLB Secondary Chemistry Form 3, Pages 3-4

GAS LAWS

Charles's Law - Introduction and Temperature Scales
Charles's Law - Experimental Investigation and Mathematical Expression
Charles's Law - Numerical Problems and Applications

By the end of the lesson, the learner should be able to:
State Charles's law
Convert temperatures between Celsius and Kelvin scales
Define absolute zero temperature
Explain the concept of absolute temperature

Teacher demonstration: Flask with colored water column experiment. Q/A: Observe volume changes with temperature. Exposition: Introduce Kelvin scale and absolute zero concept. Practice: Temperature conversions between °C and K. Discuss absolute zero and ideal gas concept.

Round-bottomed flask, Narrow glass tube, Colored water, Rubber bung, Hot and cold water baths
Glass apparatus, Thermometers, Graph papers, Water baths at different temperatures
Scientific calculators, Temperature conversion charts, Application examples

KLB Secondary Chemistry Form 3, Pages 6-8

GAS LAWS

Combined Gas Law and Standard Conditions
Introduction to Diffusion - Experimental Investigation
Rates of Diffusion - Comparative Study
Graham's Law of Diffusion - Theory and Mathematical Expression

By the end of the lesson, the learner should be able to:
Derive the combined gas law equation
Apply PV/T = constant in problem solving
Define standard temperature and pressure (s.t.p)
Define room temperature and pressure (r.t.p)
Compare diffusion rates of different gases
Investigate factors affecting diffusion rates
Measure relative distances covered by diffusing gases
Calculate rates of diffusion using distance and time data

Q/A: Combine Boyle's and Charles's laws. Teacher exposition: Derive P₁V₁/T₁ = P₂V₂/T₂. Define s.t.p (273K, 760mmHg) and r.t.p (298K, 760mmHg). Worked examples: Problems involving changes in all three variables. Supervised practice: Complex gas law calculations.
Class experiment: Ammonia and HCl diffusion in glass tube. Insert cotton wool soaked in concentrated NH₃ and HCl at opposite ends. Time the formation of white NH₄Cl ring. Measure distances covered by each gas. Calculate rates: distance/time. Compare molecular masses of NH₃ and HCl.

Scientific calculators, Combined law derivation charts, Standard conditions reference table
KMnO₄ crystals, Bromine liquid, Gas jars, Combustion tube, Litmus papers, Stopwatch
Glass tube (25cm), Cotton wool, Concentrated NH₃ and HCl, Stopwatch, Ruler, Safety equipment
Graham's law charts, Molecular mass tables, Mathematical derivation displays

KLB Secondary Chemistry Form 3, Pages 12-14
KLB Secondary Chemistry Form 3, Pages 16-18

GAS LAWS

Graham's Law - Numerical Applications and Problem Solving

By the end of the lesson, the learner should be able to:
Solve numerical problems using Graham's law
Calculate relative rates of diffusion
Determine molecular masses from diffusion data
Compare diffusion times for equal volumes of gases

Worked examples: Calculate relative diffusion rates using √(M₂/M₁). Problems involving time comparisons for equal volumes. Calculate unknown molecular masses from rate data. Supervised practice: Various Graham's law calculations. Real-life applications: gas separation, gas masks.

Scientific calculators, Worked example charts, Molecular mass reference tables

KLB Secondary Chemistry Form 3, Pages 20-22

THE MOLE

Relative Mass - Introduction and Experimental Investigation

By the end of the lesson, the learner should be able to:
Define relative mass using practical examples
Compare masses of different objects using a reference standard
Explain the concept of relative atomic mass
Identify carbon-12 as the reference standard

Experiment: Weighing different sized nails using beam balance. Use smallest nail as reference standard. Q/A: Discuss everyday examples of relative measurements. Teacher exposition: Introduction of carbon-12 scale and IUPAC recommendations. Calculate relative masses from experimental data.

Different sized nails ( 5-15cm), Beam balance, Fruits of different masses, Reference charts

KLB Secondary Chemistry Form 3, Pages 25-27

THE MOLE

Avogadro's Constant and the Mole Concept
Interconversion of Mass and Moles for Elements

By the end of the lesson, the learner should be able to:
Define Avogadro's constant and its value
Explain the concept of a mole as a counting unit
Relate molar mass to relative atomic mass
Calculate number of atoms in given masses of elements

Experiment: Determine number of nails with mass equal to relative mass in grams. Teacher exposition: Introduce Avogadro's constant (6.023 × 10²³). Discussion: Mole as counting unit like dozen. Worked examples: Calculate moles from mass and vice versa.

Beam balance, Various sized nails, Scientific calculators, Avogadro's constant charts
Scientific calculators, Periodic table, Worked example charts, Formula triangles

KLB Secondary Chemistry Form 3, Pages 27-30

THE MOLE

Molecules and Moles - Diatomic Elements
Empirical Formula - Experimental Determination

By the end of the lesson, the learner should be able to:
Distinguish between atoms and molecules
Define relative molecular mass
Calculate moles of molecules from given mass
Determine number of atoms in molecular compounds
Define empirical formula
Determine empirical formula from experimental data
Calculate mole ratios from mass data
Express results as simplest whole number ratios

Discussion: Elements existing as molecules (O₂, H₂, N₂, Cl₂). Teacher exposition: Difference between atomic and molecular mass. Worked examples: Calculate moles of molecular elements. Problem solving: Number of atoms in molecular compounds.
Experiment: Burning magnesium in air to form magnesium oxide. Measure masses before and after reaction. Calculate moles of Mg and O from mass data. Determine mole ratio and empirical formula. Safety precautions during heating.

Molecular models, Charts showing diatomic elements, Scientific calculators
Crucible and lid, Magnesium ribbon, Bunsen burner, Beam balance, Tongs, Safety equipment

KLB Secondary Chemistry Form 3, Pages 29-30
KLB Secondary Chemistry Form 3, Pages 32-35

THE MOLE

Empirical Formula - Reduction Method
Empirical Formula - Percentage Composition Method

By the end of the lesson, the learner should be able to:
Determine empirical formula using reduction reactions
Calculate empirical formula from reduction data
Apply reduction method to copper oxides
Analyze experimental errors and sources

Experiment: Reduction of copper(II) oxide using laboratory gas. Measure masses before and after reduction. Calculate moles of copper and oxygen. Determine empirical formula from mole ratios. Discuss experimental precautions.

Combustion tube, Porcelain boat, Copper(II) oxide, Laboratory gas, Beam balance, Bunsen burner
Scientific calculators, Percentage composition charts, Worked example displays

KLB Secondary Chemistry Form 3, Pages 35-37

THE MOLE

Molecular Formula - Determination from Empirical Formula

By the end of the lesson, the learner should be able to:
Define molecular formula
Relate molecular formula to empirical formula
Calculate molecular formula using molecular mass
Apply the relationship (empirical formula)ₙ = molecular formula

Teacher exposition: Difference between empirical and molecular formulas. Worked examples: Calculate molecular formula from empirical formula and molecular mass. Formula: n = molecular mass/empirical formula mass. Practice problems with various organic compounds.

Scientific calculators, Molecular mass charts, Worked example displays

KLB Secondary Chemistry Form 3, Pages 38-40

THE MOLE

Molecular Formula - Combustion Analysis

By the end of the lesson, the learner should be able to:
Determine molecular formula from combustion data
Calculate moles of products in combustion
Relate product moles to reactant composition
Apply combustion analysis to hydrocarbons

Worked examples: Hydrocarbon combustion producing CO₂ and H₂O. Calculate moles of C and H from product masses. Determine empirical formula, then molecular formula. Practice: Various combustion analysis problems.

Scientific calculators, Combustion analysis charts, Molecular models of hydrocarbons

KLB Secondary Chemistry Form 3, Pages 40-41