ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Solution of H₂SO₄ and Safety

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 considering density and percentage purity
-Explain why experimental values differ from theoretical values

Teacher demonstration: Add 2cm³ concentrated H₂SO₄ to 98cm³ water (NEVER vice versa). Record temperature change. Calculate mass using density (1.84 g/cm³) and purity (98%). Calculate molar heat of solution. Emphasize safety: always add acid to water. Discuss sources of experimental error.

Concentrated H₂SO₄, distilled water, plastic beaker, tissue paper, thermometer, safety equipment

KLB Secondary Chemistry Form 4, Pages 39-41

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
Enthalpy of Neutralization

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
- 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: 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.
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.

Zinc powder, 0.5M CuSO₄ solution, plastic beakers, thermometers, analytical balance
2M HCl, 2M NaOH, 2M ethanoic acid, 2M ammonia solution, measuring cylinders, thermometers, plastic beakers

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

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Enthalpy of Neutralization

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

KLB Secondary Chemistry Form 4, Pages 47-49

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Standard Conditions and Standard Enthalpy Changes

By the end of the lesson, the learner should be able to:
- Define standard conditions for measuring enthalpy changes
-Use standard enthalpy notation ΔH°
-Apply correct notation for different types of enthalpy changes
-Explain importance of standardization for comparison

Q/A: Review enthalpy measurements. Define standard conditions: 25°C (298K) and 1 atmosphere (101.325 kPa). Introduce ΔH° notation where θ denotes standard. Show subscripts: ΔH°c (combustion), ΔH°f (formation), ΔH°neut (neutralization), ΔH°sol (solution). Practice using correct notation in thermochemical equations.

Student books, standard enthalpy data examples, notation practice exercises

KLB Secondary Chemistry Form 4, Pages 49

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Hess's Law - Theory and Energy Cycles

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

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.

Energy cycle diagrams for methane and CO formation, combustion data, 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:
- Carry out calculations using Hess's Law
-Draw energy level diagrams
-Calculate enthalpy of formation from combustion data
-Solve worked examples using energy cycles
- 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

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.
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.

Worked examples, combustion data tables, graph paper for diagrams, calculators
Energy cycle diagrams, hydration diagram (Fig 2.17), Tables 2.6 and 2.7 with lattice/hydration energies

KLB Secondary Chemistry Form 4, Pages 52-56
KLB Secondary Chemistry Form 4, Pages 54-56

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Definition and Types of Fuels

By the end of the lesson, the learner should be able to:
- Define a fuel
-Classify fuels into solid, liquid and gaseous types
-Define heating value of a fuel
-Calculate heating values from molar enthalpies of combustion

Define fuel as "substance producing useful energy in chemical/nuclear reaction." Classify: solids (coal, charcoal, wood), liquids (petrol, kerosene, diesel), gases (natural gas, biogas, LPG). Define heating value as "heat energy per unit mass." Calculate for ethanol: -1360 kJ/mol ÷ 46 g/mol = 30 kJ/g. Compare values from Table 2.8.

Examples of local fuels, Table 2.8 showing heating values, calculators

KLB Secondary Chemistry Form 4, Pages 56-57

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Fuel Selection Factors

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

KLB Secondary Chemistry Form 4, Pages 57

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES

Fuel Selection Factors

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

KLB Secondary Chemistry Form 4, Pages 57

ENERGY CHANGES IN PHYSICAL AND CHEMICAL PROCESSES
REACTION RATES AND REVERSIBLE REACTIONS

Environmental Effects and Safety
Definition of Reaction Rate and Collision Theory

By the end of the lesson, the learner should be able to:
- Explain environmental effects of fuels
-Describe formation and effects of acid rain
-Identify measures to reduce pollution
-State safety precautions for fuel handling
- Define rate of reaction and explain the term activation energy
-Describe collision theory and explain why not all collisions result in products
-Draw energy diagrams showing activation energy
-Explain how activation energy affects reaction rates

Discuss pollutants: SO₂, NO₂ forming acid rain affecting buildings, lakes, vegetation. CO₂ causing global warming and climate change. Pollution reduction: catalytic converters, unleaded petrol, zero emission vehicles, alternative fuels. Safety: ventilation for charcoal, proper gas storage, fuel storage location, avoiding spills.
Q/A: Compare speeds of different reactions (precipitation vs rusting). Define reaction rate as "measure of how much reactants are consumed or products formed per unit time." Introduce collision theory: particles must collide with minimum energy (activation energy) for successful reaction. Draw energy diagram showing activation energy barrier. Discuss factors affecting collision frequency and energy.

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 57-58
KLB Secondary Chemistry Form 4, Pages 64-65

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Concentration on Reaction Rate

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

KLB Secondary Chemistry Form 4, Pages 65-67

REACTION RATES AND REVERSIBLE REACTIONS

Change of Reaction Rate with Time

By the end of the lesson, the learner should be able to:
- Describe methods used to measure rate of reaction
-Investigate how reaction rate changes as reaction proceeds
-Plot graphs of volume of gas vs time
-Calculate average rates at different time intervals

Class experiment: React 2cm magnesium ribbon with 100cm³ of 0.5M HCl in conical flask. Collect H₂ gas in graduated syringe as in Fig 3.4. Record gas volume every 30 seconds for 5 minutes in Table 3.2. Plot volume vs time graph. Calculate average rates between time intervals. Explain why rate decreases as reactants are consumed.

0.5M HCl, magnesium ribbon, conical flask, gas collection apparatus, graduated syringe, stopwatch, graph paper

KLB Secondary Chemistry Form 4, Pages 67-70

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Temperature 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

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.

0.15M Na₂S₂O₃, 2M HCl, conical flasks, water baths at different temperatures, paper with cross marked, stopwatch, thermometers

KLB Secondary Chemistry Form 4, Pages 70-73

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Surface Area on Reaction Rate
Effect of Catalysts on Reaction Rate

By the end of the lesson, the learner should be able to:
- Explain the effect of surface area on reaction rates
-Investigate reaction of marble chips vs marble powder with HCl
-Compare reaction rates using gas collection
-Relate particle size to surface area and collision frequency
- 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: React 2.5g marble chips with 50cm³ of 1M HCl, collect CO₂ gas using apparatus in Fig 3.10. Record gas volume every 30 seconds. Repeat with 2.5g marble powder. Record in Table 3.5. Plot both curves on same graph. Write equation: CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂. Explain: smaller particles → larger surface area → more collision sites → faster reaction.
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.

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

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

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Catalysts on Reaction Rate

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

20-volume H₂O₂, MnO₂ powder, gas collection apparatus, balance, conical flasks, filter paper, measuring cylinders

KLB Secondary Chemistry Form 4, Pages 76-78

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Light and Pressure on Reaction Rate

By the end of the lesson, the learner should be able to:
- Identify reactions affected by light
-Investigate effect of light on silver bromide decomposition
-Explain effect of pressure on gaseous reactions
-Give examples of photochemical reactions

Teacher demonstration: Mix KBr and AgNO₃ solutions to form AgBr precipitate. Divide into 3 test tubes: place one in dark cupboard, one on bench, one in direct sunlight. Observe color changes after 10 minutes. Write equations. Discuss photochemical reactions: photography, Cl₂ + H₂, photosynthesis. Explain pressure effects on gaseous reactions through compression.

0.1M KBr, 0.05M AgNO₃, test tubes, dark cupboard, direct light source, examples of photochemical reactions

KLB Secondary Chemistry Form 4, Pages 78-80

REACTION RATES AND REVERSIBLE REACTIONS

Reversible Reactions

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

KLB Secondary Chemistry Form 4, Pages 78-80

REACTION RATES AND REVERSIBLE REACTIONS

Chemical Equilibrium
Le Chatelier's Principle and Effect of Concentration

By the end of the lesson, the learner should be able to:
- Explain chemical equilibrium
-Define dynamic equilibrium
-Investigate acid-base equilibrium using indicators
-Explain why equilibrium appears static but is actually dynamic
- 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 0.5M NaOH to 2cm³ in boiling tube with universal indicator. Add 0.5M HCl dropwise until green color (neutralization point). Continue adding base then acid alternately, observe color changes. Explain equilibrium as state where forward and backward reaction rates are equal. Use NH₄Cl ⇌ NH₃ + HCl example to show dynamic nature. Introduce equilibrium symbol ⇌.
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.

0.5M NaOH, 0.5M HCl, universal indicator, boiling tubes, droppers, examples of equilibrium systems
Bromine water, 2M NaOH, 2M HCl, beakers, chromate/dichromate solutions for demonstration

KLB Secondary Chemistry Form 4, Pages 80-82
KLB Secondary Chemistry Form 4, Pages 82-84

REACTION RATES AND REVERSIBLE REACTIONS

Effect of Pressure and Temperature on Equilibrium

By the end of the lesson, the learner should be able to:
- Explain effect of pressure changes on equilibrium
-Explain effect of temperature changes on equilibrium
-Investigate NO₂/N₂O₄ equilibrium with temperature
-Apply Le Chatelier's Principle to industrial processes

Teacher demonstration: React copper turnings with concentrated HNO₃ to produce NO₂ gas in test tube. Heat and cool the tube, observe color changes: brown ⇌ pale yellow representing 2NO₂ ⇌ N₂O₄. Explain pressure effects using molecule count. Show Table 3.7 with pressure effects. Discuss temperature effects: heating favors endothermic direction, cooling favors exothermic direction. Use Table 3.8.

Copper turnings, concentrated HNO₃, test tubes, heating source, ice bath, gas collection apparatus, safety equipment

KLB Secondary Chemistry Form 4, Pages 84-87

REACTION RATES AND REVERSIBLE REACTIONS

Industrial Applications - Haber 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

KLB Secondary Chemistry Form 4, Pages 87-89

REACTION RATES AND REVERSIBLE REACTIONS

Industrial Applications - Contact Process

By the end of the lesson, the learner should be able to:
- Apply equilibrium principles to Contact Process
-Explain optimum conditions for sulphuric acid manufacture
-Compare different industrial equilibrium processes
-Evaluate economic factors in industrial chemistry

Analyze Contact Process: 2SO₂ + O₂ ⇌ 2SO₃ ΔH = -197 kJ/mol. Apply principles: high pressure favors forward reaction (3 molecules → 2 molecules), low temperature favors exothermic reaction. Explain optimum conditions: 450°C, atmospheric pressure, V₂O₅ catalyst, 96% conversion. Compare with Haber Process. Discuss catalyst choice and economic factors.

Contact Process flow diagram, comparison table with Haber Process, catalyst effectiveness data

KLB Secondary Chemistry Form 4, Pages 89

ELECTROCHEMISTRY

Redox Reactions and Oxidation Numbers
Oxidation Numbers in Naming and Redox Identification
Displacement Reactions - Metals and Halogens

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
Apply oxidation numbers to systematic naming
- Use oxidation numbers to identify redox reactions
- Distinguish oxidizing and reducing agents
- Track electron movement in reactions

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
Worked examples: Calculate oxidation numbers in complex compounds
- Practice IUPAC naming
- Exercise 4.1: Identify redox reactions using oxidation numbers
- Name compounds with variable oxidation states

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

KLB Secondary Chemistry Form 4, Pages 108-116
KLB Secondary Chemistry Form 4, Pages 109-116

ELECTROCHEMISTRY

Electrochemical Cells and Cell Diagrams
Standard Electrode Potentials

By the end of the lesson, the learner should be able to:
Define electrode potential and EMF
- Describe electrochemical cell components
- Draw cell diagrams using correct notation
- Explain electron flow and salt bridge function

Experiment 4.5: Set up Zn/Cu cell and other metal combinations
- Measure EMF values
- Practice writing cell notation
- Learn conventional representation methods

Metal electrodes, 1M metal salt solutions, voltmeters, salt bridges, connecting wires
Standard electrode potential table, diagrams, charts showing standard conditions

KLB Secondary Chemistry Form 4, Pages 123-128

ELECTROCHEMISTRY

Calculating Cell EMF and Predicting Reactions

By the end of the lesson, the learner should be able to:
Calculate EMF using standard electrode potentials
- Predict reaction spontaneity using EMF
- Solve numerical problems on cell EMF
- Apply EMF calculations practically

Worked examples: Calculate EMF for various cells
- Practice EMF calculations
- Exercise 4.2 & 4.3: Cell EMF and reaction feasibility problems
- Distinguish spontaneous from non-spontaneous reactions

Calculators, electrode potential data, worked examples, practice problems

KLB Secondary Chemistry Form 4, Pages 133-137

ELECTROCHEMISTRY

Types of Electrochemical Cells
Electrolysis of Aqueous Solutions I

By the end of the lesson, the learner should be able to:
Describe functioning of primary and secondary cells
- Compare different cell types
- Explain fuel cell operation
- State applications of electrochemical cells

Study dry cell (Le Clanche) and lead-acid accumulator
- Hydrogen-oxygen fuel cell operation
- Compare cell types and applications
- Discussion on advantages/disadvantages

Cell diagrams, sample batteries, charts showing cell applications
Dilute and concentrated NaCl solutions, carbon electrodes, gas collection tubes, test equipment

KLB Secondary Chemistry Form 4, Pages 138-141

ELECTROCHEMISTRY

Electrolysis of Aqueous Solutions II

By the end of the lesson, the learner should be able to:
Analyze electrolysis of dilute sulphuric acid
- Investigate electrolysis of metal salt solutions
- Measure gas volumes and ratios
- Apply theoretical predictions

Experiment 4.7: Electrolysis of dilute H₂SO₄ using U-tube
- Experiment 4.8: Electrolysis of MgSO₄ solution
- Collect and measure gases
- Analyze volume ratios

U-tube apparatus, 2M H₂SO₄, 0.5M MgSO₄, platinum/carbon electrodes, gas syringes

KLB Secondary Chemistry Form 4, Pages 146-148

ELECTROCHEMISTRY

Effect of Electrode Material on 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

KLB Secondary Chemistry Form 4, Pages 141-148

ELECTROCHEMISTRY

Factors Affecting Electrolysis
Applications of Electrolysis I

By the end of the lesson, the learner should be able to:
Identify factors affecting preferential discharge
- Explain electrochemical series influence
- Discuss concentration and electrode effects
- Predict electrolysis products
Describe electrolytic extraction of reactive metals
- Explain electroplating process
- Apply electrolysis principles to metal coating
- Design electroplating setup

Review electrochemical series and discharge order
- Analysis of concentration effects on product formation
- Summary of all factors affecting electrolysis
- Practice prediction problems
Discussion: Extraction of Na, Mg, Al by electrolysis
- Practical: Electroplate iron nail with copper
- Calculate plating requirements
- Industrial applications

Electrochemical series chart, summary tables, practice exercises, student books
Iron nails, copper electrodes, CuSO₄ solution, power supply, industrial process diagrams

KLB Secondary Chemistry Form 4, Pages 153-155
KLB Secondary Chemistry Form 4, Pages 155-157

ELECTROCHEMISTRY

Applications of Electrolysis II

By the end of the lesson, the learner should be able to:
Describe manufacture of NaOH and Cl₂ from brine
- Explain mercury cell operation
- Analyze industrial electrolysis processes
- Discuss environmental considerations

Study mercury cell for NaOH production
- Flow chart analysis of industrial processes
- Discussion on applications and environmental impact
- Purification of metals

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

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

KLB Secondary Chemistry Form 4, Pages 161-164

ELECTROCHEMISTRY

Faraday's Laws and Quantitative Electrolysis

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

KLB Secondary Chemistry Form 4, Pages 161-164

ELECTROCHEMISTRY

Electrolysis Calculations I
Electrolysis Calculations II

By the end of the lesson, the learner should be able to:
Calculate mass of products from electrolysis
- Determine volumes of gases evolved
- Apply Faraday's laws to numerical problems
- Solve basic electrolysis calculations
Determine charge on ions from electrolysis data
- Calculate current-time relationships
- Solve complex multi-step problems
- Apply concepts to industrial situations

Worked examples: Mass and volume calculations
- Problems involving different ions
- Practice with Faraday constant
- Basic numerical problems
Complex problems: Determine ionic charges
- Current-time-mass relationships
- Multi-step calculations
- Industrial calculation examples

Calculators, worked examples, practice problems, gas volume data, Faraday constant
Calculators, complex problem sets, industrial data, student books

KLB Secondary Chemistry Form 4, Pages 161-164

ELECTROCHEMISTRY

Advanced Applications and Problem Solving

By the end of the lesson, the learner should be able to:
Solve examination-type electrochemistry problems
- Apply all concepts in integrated problems
- Analyze real-world electrochemical processes
- Practice complex calculations

Comprehensive problems combining redox, cells, and electrolysis
- Past examination questions
- Industrial case study analysis
- Advanced problem-solving techniques

Past papers, comprehensive problem sets, industrial case studies, calculators

KLB Secondary Chemistry Form 4, Pages 108-164