ACIDS, BASES AND SALTS

Definition of Acids
Strength of Acids

By the end of the lesson, the learner should be able to:
- Define an acid in terms of hydrogen ions
-Investigate reactions of magnesium and zinc carbonate with different acids
-Write equations for reactions taking place
-Explain why magnesium strip should be cleaned

Class experiment: React cleaned magnesium strips with 2M HCl, 2M ethanoic acid, 2M H₂SO₄, 2M ethanedioic acid. Record observations in table. Repeat using zinc carbonate. Write chemical equations. Discuss hydrogen ion displacement and gas evolution.

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

KLB Secondary Chemistry Form 4, Pages 1-3

ACIDS, BASES AND SALTS

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

By the end of the lesson, the learner should be able to:
- Define a base in terms of hydroxide ions
-Investigate effect of calcium hydroxide in water
-Test solutions with litmus paper
-Explain dissociation of bases in water

Teacher demonstration: Place dry calcium hydroxide on dry red litmus paper. Dissolve calcium hydroxide in water, test with litmus paper and phenolphthalein. Discuss observations and write dissociation equation. Define bases in terms of OH⁻ ions.

Calcium hydroxide, red litmus paper, phenolphthalein indicator, distilled water, test tubes, spatula, evaporating dish
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 5-6

ACIDS, BASES AND SALTS

Effect of Solvent on Bases
Amphoteric Oxides and Hydroxides
Definition of Salts and Precipitation
Solubility of Chlorides, Sulphates and Sulphites
Complex Ions Formation

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
- 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: 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.
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.

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
2M NaCl, 2M Na₂SO₄, 2M Na₂SO₃, 0.1M salt solutions, dilute HCl, test tubes, heating source
2M NaOH, 2M NH₃ solution, 0.5M salt solutions, test tubes, droppers

KLB Secondary Chemistry Form 4, Pages 9-10
KLB Secondary Chemistry Form 4, Pages 14-16

ACIDS, BASES AND SALTS

Solubility and Saturated Solutions
Effect of Temperature 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
-Calculate mass of solute and solvent
-Express solubility in different units

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.

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 16-18

ACIDS, BASES AND SALTS

Solubility Curves and Applications
Fractional Crystallization

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

KLB Secondary Chemistry Form 4, Pages 20-21

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

Effects of Hard Water
Methods of Removing Hardness I
Methods of Removing Hardness II
Endothermic and Exothermic Reactions
Enthalpy Notation and Energy Content

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 using sodium carbonate
-Describe ion exchange method
-Explain removal using calcium hydroxide and ammonia
-Write equations for all processes

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 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.

Samples of fur deposits, pictures of scaled pipes, calculator for cost analysis
Hard water samples, heating source, soap solution, distillation apparatus diagram
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
Student books, calculators, worked examples from textbook, chalkboard for calculations

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

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Bond Breaking and Bond Formation
Latent Heat of Fusion and Vaporization

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
Data tables showing molar heats of fusion/vaporization, calculators, heating curves from previous lesson

KLB Secondary Chemistry Form 4, Pages 32-35

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Bond Energy Calculations
Determination of Enthalpy of Solution I

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

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.

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 35-36

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Thermochemical Equations
Enthalpy of Solution of Concentrated Sulphuric Acid

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

KLB Secondary Chemistry Form 4, Pages 38-39

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Combustion
Enthalpy of Displacement
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 combustion
-Determine enthalpy of combustion of ethanol experimentally
-Explain why experimental values differ from theoretical values
-Calculate molar enthalpy of combustion from experimental data
- 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

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.
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.

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
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 41-44
KLB Secondary Chemistry Form 4, Pages 47-49

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
Lattice Energy and Hydration Energy

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
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

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

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.

Data tables from textbook, calculators, trend analysis exercises
Examples of different fuels, classification charts, pictures of fuel types

KLB Secondary Chemistry Form 4, Pages 54-56

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Heating Values of Fuels
Factors in Fuel Selection
Environmental Effects of Fuels
Fuel Safety and Precautions

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

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.
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.

Heating value data table, calculators, fuel comparison charts
Fuel comparison tables, local fuel availability data, cost analysis sheets
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 56-57
KLB Secondary Chemistry Form 4, Pages 57-58

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Endothermic and Exothermic Reactions
Bond Breaking, Formation and Phase Changes

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
Ice, glass beakers, thermometers, heating source, graph paper, bond energy data tables

KLB Secondary Chemistry Form 4, Pages 29-32

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Determination of Enthalpy of Solution
Enthalpy of Solution of H₂SO₄ and Safety

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

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 36-39

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

KLB Secondary Chemistry Form 4, Pages 41-44

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Neutralization
Standard Conditions and Standard Enthalpy Changes
Hess's Law - Theory and Energy Cycles
Hess's Law Calculations

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
- 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

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.
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.

2M HCl, 2M NaOH, 2M ethanoic acid, 2M ammonia solution, measuring cylinders, thermometers, plastic beakers
Student books, standard enthalpy data examples, notation practice 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 47-49
KLB Secondary Chemistry Form 4, Pages 49-52

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
REACTION RATES AND REVERSIBLE REACTIONS

Fuel Selection Factors
Environmental Effects and Safety
Definition of Reaction Rate and Collision Theory

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
Examples of fast/slow reactions, energy diagram templates, chalk/markers for diagrams

KLB Secondary Chemistry Form 4, Pages 57

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Concentration on Reaction Rate
Change of Reaction Rate with Time

By the end of the lesson, the learner should be able to:
- Explain the effect of concentration on reaction rates
-Investigate reaction of magnesium with different concentrations of sulphuric acid
-Illustrate reaction rates graphically and interpret experimental data
-Calculate concentrations and plot graphs of concentration vs time

Class experiment: Label 4 conical flasks A-D. Add 40cm³ of 2M H₂SO₄ to A, dilute others with water (30+10, 20+20, 10+30 cm³). Drop 2cm magnesium ribbon into each, time complete dissolution. Record in Table 3.1. Calculate concentrations, plot graph. Explain: higher concentration → more collisions → faster reaction.

4 conical flasks, 2M H₂SO₄, distilled water, magnesium ribbon, stopwatch, measuring cylinders, graph paper
0.5M HCl, magnesium ribbon, conical flask, gas collection apparatus, graduated syringe, stopwatch, graph paper

KLB Secondary Chemistry Form 4, Pages 65-67

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Temperature on Reaction Rate
Effect of Surface Area on Reaction Rate
Effect of Catalysts on Reaction Rate
Effect of Light and Pressure on Reaction Rate

By the end of the lesson, the learner should be able to:
- Explain the effect of temperature on reaction rates
-Investigate temperature effects using sodium thiosulphate and HCl
-Plot graphs of time vs temperature and 1/time vs temperature
-Apply collision theory to explain temperature effects
- Explain effects of suitable catalysts on reaction rates
-Investigate decomposition of hydrogen peroxide with and without catalyst
-Define catalyst and explain how catalysts work
-Compare activation energies in catalyzed vs uncatalyzed reactions

Class experiment: Place 30cm³ of 0.15M Na₂S₂O₃ in flasks at room temp, 30°C, 40°C, 50°C, 60°C. Mark cross on paper under flask. Add 5cm³ of 2M HCl, time until cross disappears. Record in Table 3.4. Plot time vs temperature and 1/time vs temperature graphs. Explain: higher temperature → more kinetic energy → more effective collisions.
Class experiment: Decompose 5cm³ of 20-volume H₂O₂ in 45cm³ water without catalyst, collect O₂ gas. Repeat adding 2g MnO₂ powder. Record gas volumes as in Fig 3.12. Compare rates and final mass of MnO₂. Write equation: 2H₂O₂ → 2H₂O + O₂. Define catalyst and explain how it lowers activation energy. Show energy diagrams for both pathways.

0.15M Na₂S₂O₃, 2M HCl, conical flasks, water baths at different temperatures, paper with cross marked, stopwatch, thermometers
Marble chips, marble powder, 1M HCl, gas collection apparatus, balance, conical flasks, measuring cylinders, graph paper
20-volume H₂O₂, MnO₂ powder, gas collection apparatus, balance, conical flasks, filter paper, measuring cylinders
0.1M KBr, 0.05M AgNO₃, test tubes, dark cupboard, direct light source, examples of photochemical reactions

KLB Secondary Chemistry Form 4, Pages 70-73
KLB Secondary Chemistry Form 4, Pages 76-78

REACTION RATES AND REVERSIBLE REACTIONS

Reversible Reactions
Chemical Equilibrium

By the end of the lesson, the learner should be able to:
- State examples of simple reversible reactions
-Investigate heating of hydrated copper(II) sulphate
-Write equations for reversible reactions using double arrows
-Distinguish between reversible and irreversible reactions

Class experiment: Heat CuSO₄·5H₂O crystals in boiling tube A, collect liquid in tube B as in Fig 3.15. Observe color changes: blue → white + colorless liquid. Pour liquid back into tube A, observe return to blue. Write equation with double arrows: CuSO₄·5H₂O ⇌ CuSO₄ + 5H₂O. Give other examples: NH₄Cl ⇌ NH₃ + HCl. Compare with irreversible reactions.

CuSO₄·5H₂O crystals, boiling tubes, delivery tube, heating source, test tube holder
0.5M NaOH, 0.5M HCl, universal indicator, boiling tubes, droppers, examples of equilibrium systems

KLB Secondary Chemistry Form 4, Pages 78-80

REACTION RATES AND REVERSIBLE REACTIONS

Le Chatelier's Principle and Effect of Concentration
Effect of Pressure and Temperature on Equilibrium

By the end of the lesson, the learner should be able to:
- State Le Chatelier's Principle
-Explain effect of concentration changes on equilibrium position
-Investigate bromine water equilibrium with acid/base addition
-Apply Le Chatelier's Principle to predict equilibrium shifts

Experiment: Add 2M NaOH dropwise to 20cm³ bromine water until colorless. Then add 2M HCl until excess, observe color return. Write equation: Br₂ + H₂O ⇌ HBr + HBrO. Explain Le Chatelier's Principle: "When change applied to system at equilibrium, system moves to oppose that change." Demonstrate with chromate/dichromate equilibrium: CrO₄²⁻ + H⁺ ⇌ Cr₂O₇²⁻ + H₂O.

Bromine water, 2M NaOH, 2M HCl, beakers, chromate/dichromate solutions for demonstration
Copper turnings, concentrated HNO₃, test tubes, heating source, ice bath, gas collection apparatus, safety equipment

KLB Secondary Chemistry Form 4, Pages 82-84

REACTION RATES AND REVERSIBLE REACTIONS

Industrial Applications - Haber Process
Industrial Applications - Contact Process

By the end of the lesson, the learner should be able to:
- Apply equilibrium principles to Haber Process
-Explain optimum conditions for ammonia manufacture
-Calculate effect of temperature and pressure on yield
-Explain role of catalysts in industrial processes

Analyze Haber Process: N₂ + 3H₂ ⇌ 2NH₃ ΔH = -92 kJ/mol. Apply Le Chatelier's Principle: high pressure favors forward reaction (4 molecules → 2 molecules), low temperature favors exothermic forward reaction but slows rate. Explain optimum conditions: 450°C temperature, 200 atmospheres pressure, iron catalyst. Discuss removal of NH₃ to shift equilibrium right. Economic considerations.

Haber Process flow diagram, equilibrium data showing temperature/pressure effects on NH₃ yield, industrial catalyst information
Contact Process flow diagram, comparison table with Haber Process, catalyst effectiveness data

KLB Secondary Chemistry Form 4, Pages 87-89

ELECTROCHEMISTRY

Redox Reactions and Oxidation Numbers
Oxidation Numbers in Naming and Redox Identification
Displacement Reactions - Metals and Halogens
Electrochemical Cells and Cell Diagrams
Standard Electrode Potentials
Calculating Cell EMF and Predicting Reactions
Types of Electrochemical Cells
Electrolysis of Aqueous Solutions I
Electrolysis of Aqueous Solutions II

By the end of the lesson, the learner should be able to:
Define redox reactions in terms of electron transfer
- State rules for assigning oxidation numbers
- Calculate oxidation numbers in compounds
- Identify oxidation and reduction processes
Define standard electrode potential
- Describe standard hydrogen electrode
- List standard conditions
- Use electrode potential tables effectively

Q/A: Review previous knowledge
- Experiment 4.1: Iron filings + copper(II) sulphate
- Experiment 4.2: Iron(II) ions + hydrogen peroxide
- Discussion on oxidation number rules with examples
Study standard hydrogen electrode setup
- Discussion of standard conditions (25°C, 1M, 1 atm)
- Introduction to electrode potential series
- Practice reading potential tables

Iron filings, 1M CuSO₄, 1M FeSO₄, 2M NaOH, 20V H₂O₂, test tubes
Compound charts, calculators, student books, practice exercises
Various metals (Ca, Mg, Zn, Fe, Pb, Cu), metal salt solutions, halogens (Cl₂, Br₂, I₂), halide solutions
Metal electrodes, 1M metal salt solutions, voltmeters, salt bridges, connecting wires
Standard electrode potential table, diagrams, charts showing standard conditions
Calculators, electrode potential data, worked examples, practice problems
Cell diagrams, sample batteries, charts showing cell applications
Dilute and concentrated NaCl solutions, carbon electrodes, gas collection tubes, test equipment
U-tube apparatus, 2M H₂SO₄, 0.5M MgSO₄, platinum/carbon electrodes, gas syringes

KLB Secondary Chemistry Form 4, Pages 108-116
KLB Secondary Chemistry Form 4, Pages 129-133

ELECTROCHEMISTRY

Effect of Electrode Material on Electrolysis
Factors Affecting Electrolysis

By the end of the lesson, the learner should be able to:
Compare inert vs reactive electrodes
- Investigate electrode dissolution
- Explain electrode selection importance
- Analyze copper purification process

Experiment 4.9: Electrolysis of CuSO₄ with carbon vs copper electrodes
- Weigh electrodes before/after
- Observe color changes
- Discussion on electrode effects

Copper and carbon electrodes, 3M CuSO₄ solution, accurate balance, beakers, connecting wires
Electrochemical series chart, summary tables, practice exercises, student books

KLB Secondary Chemistry Form 4, Pages 141-148

ELECTROCHEMISTRY

Applications of Electrolysis I
Applications of Electrolysis II

By the end of the lesson, the learner should be able to:
Describe electrolytic extraction of reactive metals
- Explain electroplating process
- Apply electrolysis principles to metal coating
- Design electroplating setup

Discussion: Extraction of Na, Mg, Al by electrolysis
- Practical: Electroplate iron nail with copper
- Calculate plating requirements
- Industrial applications

Iron nails, copper electrodes, CuSO₄ solution, power supply, industrial process diagrams
Flow charts, mercury cell diagrams, environmental impact data, industrial case studies

KLB Secondary Chemistry Form 4, Pages 155-157

ELECTROCHEMISTRY

Faraday's Laws and Quantitative Electrolysis
Electrolysis Calculations I

By the end of the lesson, the learner should be able to:
State Faraday's laws of electrolysis
- Define Faraday constant
- Calculate mass deposited in electrolysis
- Relate electricity to amount of substance

Experiment 4.10: Quantitative electrolysis of CuSO₄
- Measure mass vs electricity passed
- Calculate Faraday constant
- Verify Faraday's laws

Accurate balance, copper electrodes, CuSO₄ solution, ammeter, timer, calculators
Calculators, worked examples, practice problems, gas volume data, Faraday constant

KLB Secondary Chemistry Form 4, Pages 161-164

ELECTROCHEMISTRY
METALS

Electrolysis Calculations II
Advanced Applications and Problem Solving
Chief Ores of Metals and General Extraction Methods
Occurrence and Extraction of Sodium
Occurrence and Extraction of Aluminium I
Extraction of Aluminium II - Electrolysis

By the end of the lesson, the learner should be able to:
Determine charge on ions from electrolysis data
- Calculate current-time relationships
- Solve complex multi-step problems
- Apply concepts to industrial situations
Name chief ores of common metals
- State formulas of metal ores
- Explain general methods of ore concentration
- Describe factors affecting extraction methods

Complex problems: Determine ionic charges
- Current-time-mass relationships
- Multi-step calculations
- Industrial calculation examples
Q/A: Review metallic bonding and reactivity
- Study Table 5.1 - metal ores and formulas
- Discussion on ore concentration methods
- Froth flotation demonstration

Calculators, complex problem sets, industrial data, student books
Past papers, comprehensive problem sets, industrial case studies, calculators
Chart of metal ores, ore samples if available, Table 5.1, flotation apparatus demonstration
Down's cell diagram, charts showing sodium occurrence, electrode reaction equations
Bauxite samples, NaOH solution, charts showing aluminium extraction steps, chemical equations
Electrolytic cell diagram, cryolite samples, graphite electrodes, energy consumption data

KLB Secondary Chemistry Form 4, Pages 161-164
KLB Secondary Chemistry Form 4, Pages 139-140

METALS

Occurrence and Extraction of Iron
Extraction of Zinc
Extraction of Lead and Copper
Physical Properties of Metals

By the end of the lesson, the learner should be able to:
Describe iron ores and occurrence
- Explain blast furnace operation
- Write equations for iron extraction reactions
- Describe slag formation process

Study iron ores and blast furnace structure
- Analysis of temperature zones in furnace
- Write reduction equations
- Discussion on limestone role and slag formation

Blast furnace diagram, iron ore samples, coke, limestone, temperature zone charts
Zinc ore samples, flow charts showing both methods, electrolytic cell diagrams
Lead and copper ore samples, extraction flow charts, electrolytic purification diagrams
Table 5.2, metal samples, conductivity apparatus, density measurement equipment

KLB Secondary Chemistry Form 4, Pages 143-145

METALS

Chemical Properties I - Reaction with Air
Chemical Properties II - Reaction with Water

By the end of the lesson, the learner should be able to:
Investigate metal reactions with air and oxygen
- Write balanced equations for metal oxidation
- Compare reactivity patterns
- Explain tarnishing and oxide formation

Experiment 5.1: Heat metals in air - sodium, aluminium, zinc, iron, copper
- Observe color changes and products
- Record observations in Table 5.3
- Write oxidation equations

Deflagrating spoons, metal samples (Na, Al, Zn, Fe, Cu), Bunsen burners, safety equipment
Metal samples, cold water, steam generator, test tubes, universal indicator, safety equipment

KLB Secondary Chemistry Form 4, Pages 152-154

METALS

Chemical Properties III - Reaction with Chlorine
Chemical Properties IV - Reaction with Acids

By the end of the lesson, the learner should be able to:
Investigate metal reactions with chlorine gas
- Write equations for chloride formation
- Compare reaction vigor
- Observe product characteristics

Experiment 5.3: React hot metals with chlorine gas (FUME CUPBOARD)
- Observe color changes and fume formation
- Record all observations
- Write balanced equations

Chlorine gas, gas jars, metal samples, tongs, deflagrating spoons, fume cupboard, safety equipment
Various acids (dilute and concentrated), metal strips, test tubes, gas collection apparatus, safety equipment

KLB Secondary Chemistry Form 4, Pages 156-157

METALS
METALS
ORGANIC CHEMISTRY II
ORGANIC CHEMISTRY II

Uses of Metals I - Sodium and Aluminium
Uses of Metals II - Zinc, Copper and Iron
Steel Types and Alloys
Environmental Effects of Metal Extraction
Introduction to Alkanols and Nomenclature
Isomerism in Alkanols

By the end of the lesson, the learner should be able to:
State uses of sodium and its compounds
- Explain aluminium applications
- Relate properties to uses
- Describe alloy formation and uses
Identify environmental impacts of mining
- Explain pollution from metal extraction
- Describe waste management strategies
- Discuss NEMA regulations in Kenya

Discussion on sodium uses in industry
- Aluminium applications in transport and construction
- Study duralumin and other alloys
- Property-use relationships
Analysis of mining environmental impact
- Air, water, and land pollution from extraction
- Waste management and slag utilization
- NEMA role and regulations

Charts showing metal applications, alloy samples, aircraft parts, cooking vessels
Galvanized sheets, copper wires, steel samples, alloy composition charts, brass and bronze samples
Steel samples with different compositions, carbon content charts, specialized tools, stainless steel items
Environmental impact case studies, pollution images, NEMA regulation documents, waste management examples
Molecular models, Table 6.1 and 6.2, alkanol structure charts, student books
Isomer structure charts, molecular models, practice worksheets, student books

KLB Secondary Chemistry Form 4, Pages 158-159
KLB Secondary Chemistry Form 4, Pages 161-162

ORGANIC CHEMISTRY II

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:
Describe fermentation process
- Prepare ethanol in laboratory
- Write equation for glucose fermentation
- Explain role of yeast and conditions needed

Experiment 6.1: Fermentation of sugar solution with yeast
- Set up apparatus for 2-3 days
- Observe gas evolution
- Test for CO₂ with lime water
- Smell final product

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 171-172

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

KLB Secondary Chemistry Form 4, Pages 180-182

ORGANIC CHEMISTRY II

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

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

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

ORGANIC CHEMISTRY II

Addition Polymers - Types and Properties
Condensation Polymerization and Natural Polymers
Polymer Properties and Applications
Comprehensive Problem Solving and Integration

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
Table 6.10, polymer application samples, environmental impact studies, product examples
Comprehensive problem sets, past examination papers, calculators, organic chemistry summary charts

KLB Secondary Chemistry Form 4, Pages 195-197