ACIDS, BASES AND SALTS

Definition 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

KLB Secondary Chemistry Form 4, Pages 1-3

ACIDS, BASES AND SALTS

Definition 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

KLB Secondary Chemistry Form 4, Pages 1-3

ACIDS, BASES AND SALTS

Strength of Acids
Definition of Bases

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

Class experiment: Test pH of 2M HCl and 2M ethanoic acid using universal indicator. Set up electrical conductivity apparatus with both acids. Record milliammeter readings. Compare results and explain in terms of hydrogen ion concentration. Discuss strong vs weak acid definitions.
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.

2M HCl, 2M ethanoic acid, universal indicator, pH chart, electrical conductivity apparatus, milliammeter, carbon electrodes, beakers, wires
Calcium hydroxide, red litmus paper, phenolphthalein indicator, distilled water, test tubes, spatula, evaporating dish

KLB Secondary Chemistry Form 4, Pages 3-5
KLB Secondary Chemistry Form 4, Pages 5-6

ACIDS, BASES AND SALTS

Definition of Bases

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

KLB Secondary Chemistry Form 4, Pages 5-6

ACIDS, BASES AND SALTS

Strength of Bases

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

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

2M NaOH, 2M ammonia solution, universal indicator, pH chart, electrical conductivity apparatus, milliammeter, carbon electrodes

KLB Secondary Chemistry Form 4, Pages 5-7

ACIDS, BASES AND SALTS

Strength of Bases

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

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

2M NaOH, 2M ammonia solution, universal indicator, pH chart, electrical conductivity apparatus, milliammeter, carbon electrodes

KLB Secondary Chemistry Form 4, Pages 5-7

ACIDS, BASES AND SALTS

Acid-Base Reactions
Effect of Solvent on Acids

By the end of the lesson, the learner should be able to:
- Write equations for acid-base reactions
-Explain neutralization process
-Identify products of acid-base reactions
-Demonstrate formation of salt and water
- Explain effect of polar and non-polar solvents on hydrogen chloride
-Investigate HCl behavior in water vs methylbenzene
-Define polar and non-polar solvents
-Explain why acids show properties only in polar solvents

Q/A: Review acid and base definitions. Demonstrate neutralization reactions: HCl + NaOH, H₂SO₄ + Ca(OH)₂, HNO₃ + KOH. Write molecular and ionic equations. Explain H⁺ + OH⁻ → H₂O. Discuss salt formation. Use indicators to show neutralization point.
Teacher demonstration: Dissolve HCl gas in water and methylbenzene separately. Test both solutions with litmus paper, magnesium, and calcium carbonate. Compare observations. Explain polarity of water vs methylbenzene. Discuss dissociation vs molecular solution.

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 6-7
KLB Secondary Chemistry Form 4, Pages 7-9

ACIDS, BASES AND SALTS

Effect of Solvent on Acids

By the end of the lesson, the learner should be able to:
- Explain effect of polar and non-polar solvents on hydrogen chloride
-Investigate HCl behavior in water vs methylbenzene
-Define polar and non-polar solvents
-Explain why acids show properties only in polar solvents

Teacher demonstration: Dissolve HCl gas in water and methylbenzene separately. Test both solutions with litmus paper, magnesium, and calcium carbonate. Compare observations. Explain polarity of water vs methylbenzene. Discuss dissociation vs molecular solution.

HCl gas, distilled water, methylbenzene, magnesium ribbon, calcium carbonate, litmus paper, test tubes, gas absorption apparatus

KLB Secondary Chemistry Form 4, Pages 7-9

ACIDS, BASES AND SALTS

Effect of Solvent on Bases

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

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

Dry ammonia gas, distilled water, methylbenzene, red litmus paper, test tubes, gas collection apparatus

KLB Secondary Chemistry Form 4, Pages 9-10

ACIDS, BASES AND SALTS

Effect of Solvent on Bases

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

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

Dry ammonia gas, distilled water, methylbenzene, red litmus paper, test tubes, gas collection apparatus

KLB Secondary Chemistry Form 4, Pages 9-10

ACIDS, BASES AND SALTS

Amphoteric Oxides and Hydroxides
Definition of Salts and Precipitation

By the end of the lesson, the learner should be able to:
- Define amphoteric oxides
-Identify some amphoteric oxides
-Investigate reactions with both acids and alkalis
-Write equations for amphoteric behavior
- Define a salt as an ionic compound
-Define a precipitate
-Investigate precipitation reactions
-Write ionic equations showing formation of precipitates

Class experiment: React Al₂O₃, ZnO, PbO, Zn(OH)₂, Al(OH)₃, Pb(OH)₂ with 2M HNO₃ and 2M NaOH. Warm mixtures. Record observations in table. Write equations showing basic and acidic behavior. Discuss dual nature of amphoteric substances.
Q/A: Review salt definition from Book 2. Demonstrate precipitation: Add sodium carbonate to solutions containing Mg²⁺, Ca²⁺, Zn²⁺, Al³⁺, Cu²⁺, Fe²⁺, Ba²⁺, Pb²⁺ ions. Record observations. Write ionic equations for precipitate formation. Explain why Fe³⁺ and Al³⁺ give different results.

Al₂O₃, ZnO, PbO, Zn(OH)₂, Al(OH)₃, Pb(OH)₂, 2M HNO₃, 2M NaOH, boiling tubes, heating source
Na₂CO₃ solution, salt solutions containing various metal ions, test tubes, droppers

KLB Secondary Chemistry Form 4, Pages 10-11
KLB Secondary Chemistry Form 4, Pages 11-14

ACIDS, BASES AND SALTS

Definition of Salts and Precipitation

By the end of the lesson, the learner should be able to:
- Define a salt as an ionic compound
-Define a precipitate
-Investigate precipitation reactions
-Write ionic equations showing formation of precipitates

Q/A: Review salt definition from Book 2. Demonstrate precipitation: Add sodium carbonate to solutions containing Mg²⁺, Ca²⁺, Zn²⁺, Al³⁺, Cu²⁺, Fe²⁺, Ba²⁺, Pb²⁺ ions. Record observations. Write ionic equations for precipitate formation. Explain why Fe³⁺ and Al³⁺ give different results.

Na₂CO₃ solution, salt solutions containing various metal ions, test tubes, droppers

KLB Secondary Chemistry Form 4, Pages 11-14

ACIDS, BASES AND SALTS

Solubility of Chlorides, Sulphates and Sulphites

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

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

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

KLB Secondary Chemistry Form 4, Pages 14-16

ACIDS, BASES AND SALTS

Solubility of Chlorides, Sulphates and Sulphites

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

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

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

KLB Secondary Chemistry Form 4, Pages 14-16

ACIDS, BASES AND SALTS

Solubility of Chlorides, Sulphates and Sulphites
Complex Ions Formation

By the end of the lesson, the learner should be able to:
- Find out cations that form insoluble chlorides, sulphates and sulphites
-Write ionic equations for formation of insoluble salts
-Distinguish between sulphate and sulphite precipitates
-Investigate effect of warming on precipitates
- Explain formation of complex ions
-Investigate reactions with excess sodium hydroxide and ammonia
-Identify metal ions that form complex ions
-Write equations for complex ion formation

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.
Class experiment: Add NaOH dropwise then in excess to Mg²⁺, Ca²⁺, Zn²⁺, Al³⁺, Cu²⁺, Fe²⁺, Fe³⁺, Pb²⁺ solutions. Repeat with NH₃ solution. Record observations showing precipitate formation and dissolution. Write equations for complex ion formation: [Zn(OH)₄]²⁻, [Al(OH)₄]⁻, [Pb(OH)₄]²⁻, [Zn(NH₃)₄]²⁺, [Cu(NH₃)₄]²⁺.

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 14-16
KLB Secondary Chemistry Form 4, Pages 15-16

ACIDS, BASES AND SALTS

Complex Ions Formation

By the end of the lesson, the learner should be able to:
- Explain formation of complex ions
-Investigate reactions with excess sodium hydroxide and ammonia
-Identify metal ions that form complex ions
-Write equations for complex ion formation

Class experiment: Add NaOH dropwise then in excess to Mg²⁺, Ca²⁺, Zn²⁺, Al³⁺, Cu²⁺, Fe²⁺, Fe³⁺, Pb²⁺ solutions. Repeat with NH₃ solution. Record observations showing precipitate formation and dissolution. Write equations for complex ion formation: [Zn(OH)₄]²⁻, [Al(OH)₄]⁻, [Pb(OH)₄]²⁻, [Zn(NH₃)₄]²⁺, [Cu(NH₃)₄]²⁺.

2M NaOH, 2M NH₃ solution, 0.5M salt solutions, test tubes, droppers

KLB Secondary Chemistry Form 4, Pages 15-16

ACIDS, BASES AND SALTS

Solubility and Saturated Solutions

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

KLB Secondary Chemistry Form 4, Pages 16-18

ACIDS, BASES AND SALTS

Solubility and Saturated Solutions

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

KLB Secondary Chemistry Form 4, Pages 16-18

ACIDS, BASES AND SALTS

Solubility and Saturated Solutions

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

KLB Secondary Chemistry Form 4, Pages 16-18

ACIDS, BASES AND SALTS

Solubility and Saturated Solutions

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

KLB Secondary Chemistry Form 4, Pages 16-18

ACIDS, BASES AND SALTS

Effect of Temperature on Solubility

By the end of the lesson, the learner should be able to:
- Investigate the effect of temperature on solubility of potassium chlorate
-Record temperature at which crystals appear
-Calculate solubility at different temperatures
-Plot solubility curve

Class experiment: Dissolve 4g KClO₃ in 15cm³ water by warming. Cool while stirring and note crystallization temperature. Add 5cm³ water portions and repeat until total volume is 40cm³. Calculate solubility in g/100g water for each temperature. Plot solubility vs temperature graph.

KClO₃, measuring cylinders, thermometer, burette, boiling tubes, heating source, graph paper

KLB Secondary Chemistry Form 4, Pages 18-20

ACIDS, BASES AND SALTS

Effect of Temperature on Solubility

By the end of the lesson, the learner should be able to:
- Investigate the effect of temperature on solubility of potassium chlorate
-Record temperature at which crystals appear
-Calculate solubility at different temperatures
-Plot solubility curve

Class experiment: Dissolve 4g KClO₃ in 15cm³ water by warming. Cool while stirring and note crystallization temperature. Add 5cm³ water portions and repeat until total volume is 40cm³. Calculate solubility in g/100g water for each temperature. Plot solubility vs temperature graph.

KClO₃, measuring cylinders, thermometer, burette, boiling tubes, heating source, graph paper

KLB Secondary Chemistry Form 4, Pages 18-20

ACIDS, BASES AND SALTS

Solubility Curves and Applications

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

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

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

KLB Secondary Chemistry Form 4, Pages 20-21

ACIDS, BASES AND SALTS

Solubility Curves and Applications

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

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

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

KLB Secondary Chemistry Form 4, Pages 20-21

ACIDS, BASES AND SALTS

Fractional Crystallization

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

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

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

KLB Secondary Chemistry Form 4, Pages 21-22

ACIDS, BASES AND SALTS

Fractional Crystallization

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

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

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

KLB Secondary Chemistry Form 4, Pages 21-22

ACIDS, BASES AND SALTS

Fractional Crystallization

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

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

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

KLB Secondary Chemistry Form 4, Pages 21-22

ACIDS, BASES AND SALTS

Hardness of Water - Investigation

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

KLB Secondary Chemistry Form 4, Pages 22-24

ACIDS, BASES AND SALTS

Types and Causes of Water Hardness

By the end of the lesson, the learner should be able to:
- Define temporary and permanent hardness
-Explain causes of temporary hardness
-Explain causes of permanent hardness
-Write equations for decomposition of hydrogen carbonates

Q/A: Review previous experiment results. Explain temporary hardness caused by Ca(HCO₃)₂ and Mg(HCO₃)₂. Write decomposition equations when boiled. Explain permanent hardness caused by CaSO₄, MgSO₄, Ca(NO₃)₂, Mg(NO₃)₂. Discuss why permanent hardness cannot be removed by boiling.

Student books, examples from previous experiment, chalkboard for equations

KLB Secondary Chemistry Form 4, Pages 24-25

ACIDS, BASES AND SALTS

Types and Causes of Water Hardness

By the end of the lesson, the learner should be able to:
- Define temporary and permanent hardness
-Explain causes of temporary hardness
-Explain causes of permanent hardness
-Write equations for decomposition of hydrogen carbonates

Q/A: Review previous experiment results. Explain temporary hardness caused by Ca(HCO₃)₂ and Mg(HCO₃)₂. Write decomposition equations when boiled. Explain permanent hardness caused by CaSO₄, MgSO₄, Ca(NO₃)₂, Mg(NO₃)₂. Discuss why permanent hardness cannot be removed by boiling.

Student books, examples from previous experiment, chalkboard for equations

KLB Secondary Chemistry Form 4, Pages 24-25

ACIDS, BASES AND SALTS

Types and Causes of Water Hardness

By the end of the lesson, the learner should be able to:
- Define temporary and permanent hardness
-Explain causes of temporary hardness
-Explain causes of permanent hardness
-Write equations for decomposition of hydrogen carbonates

Q/A: Review previous experiment results. Explain temporary hardness caused by Ca(HCO₃)₂ and Mg(HCO₃)₂. Write decomposition equations when boiled. Explain permanent hardness caused by CaSO₄, MgSO₄, Ca(NO₃)₂, Mg(NO₃)₂. Discuss why permanent hardness cannot be removed by boiling.

Student books, examples from previous experiment, chalkboard for equations

KLB Secondary Chemistry Form 4, Pages 24-25

ACIDS, BASES AND SALTS

Types and Causes of Water Hardness

By the end of the lesson, the learner should be able to:
- Define temporary and permanent hardness
-Explain causes of temporary hardness
-Explain causes of permanent hardness
-Write equations for decomposition of hydrogen carbonates

Q/A: Review previous experiment results. Explain temporary hardness caused by Ca(HCO₃)₂ and Mg(HCO₃)₂. Write decomposition equations when boiled. Explain permanent hardness caused by CaSO₄, MgSO₄, Ca(NO₃)₂, Mg(NO₃)₂. Discuss why permanent hardness cannot be removed by boiling.

Student books, examples from previous experiment, chalkboard for equations

KLB Secondary Chemistry Form 4, Pages 24-25

ACIDS, BASES AND SALTS

Effects of Hard Water

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

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.

Samples of fur deposits, pictures of scaled pipes, calculator for cost analysis

KLB Secondary Chemistry Form 4, Pages 24-25

ACIDS, BASES AND SALTS

Effects of Hard Water
Methods of Removing Hardness I

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

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

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

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

ACIDS, BASES AND SALTS

Methods of Removing Hardness I

By the end of the lesson, the learner should be able to:
- Explain removal of hardness by boiling
-Explain removal by distillation
-Write equations for these processes
-Compare effectiveness of different methods

Demonstrate boiling method: Boil hard water samples from previous experiments and test with soap. Write equations for Ca(HCO₃)₂ and Mg(HCO₃)₂ decomposition. Discuss distillation method using apparatus setup. Compare costs and effectiveness. Explain why boiling only removes temporary hardness.

Hard water samples, heating source, soap solution, distillation apparatus diagram

KLB Secondary Chemistry Form 4, Pages 25-26

ACIDS, BASES AND SALTS

Methods of Removing Hardness II

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

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

Na₂CO₃ solution, hard water samples, ion exchange resin diagram, Ca(OH)₂, NH₃ solution

KLB Secondary Chemistry Form 4, Pages 25-26

ACIDS, BASES AND SALTS

Methods of Removing Hardness II

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

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

Na₂CO₃ solution, hard water samples, ion exchange resin diagram, Ca(OH)₂, NH₃ solution

KLB Secondary Chemistry Form 4, Pages 25-26

ACIDS, BASES AND SALTS

Methods of Removing Hardness II

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

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

Na₂CO₃ solution, hard water samples, ion exchange resin diagram, Ca(OH)₂, NH₃ solution

KLB Secondary Chemistry Form 4, Pages 25-26

ACIDS, BASES AND SALTS

Methods of Removing Hardness II

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

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

Na₂CO₃ solution, hard water samples, ion exchange resin diagram, Ca(OH)₂, NH₃ solution

KLB Secondary Chemistry Form 4, Pages 25-26