Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 3rd Term
Week: 4
Age: 15 years
Duration: 45 minutes
Subject: Chemistry
Curriculum Theme: Chemistry
Previous Lesson: .
Topic: Carbon and Its Compounds
Subject Matter: Oxides of carbon (carbon(IV) oxide and carbon(II) oxide), synthetic gas manufacture and uses, and properties of trioxocarbonate(IV) salts

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

define carbon(IV) oxide and carbon(II) oxide and state their chemical formulae.
compare carbon(IV) oxide and carbon(II) oxide in physical properties and chemical behaviour.
state the manufacture and uses of synthetic gas (syngas).
identify common trioxocarbonate(IV) salts and state their properties.
state the reactions of carbonates with acids and the test for carbon(IV) oxide.

Affective Domain:

show safety awareness about poisonous gases, especially carbon(II) oxide.
demonstrate care in observing experiments and recording results accurately.

Psychomotor Domain:

observe simple demonstrations showing properties of carbon(IV) oxide and carbonates.
carry out or describe the carbon dioxide test using limewater and record observations.
write correct chemical equations for key reactions involving carbon oxides, syngas reactions, and carbonates.

work in groups to compare observations and present a clear summary of differences between carbon(IV) oxide and carbon(II) oxide.
share materials responsibly and participate in group reporting.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum (NERDC).
State Unified Scheme of Work.
Ababio, O. Y. New School Chemistry for Senior Secondary Schools.
OpenStax Chemistry 2e: Occurrence, Preparation, and Properties of Carbonates.
Royal Society of Chemistry: Test for Carbon Dioxide from Carbonates (limewater test).
Chem LibreTexts: Synthesis Gas (Syngas) and Uses.
Encyclopaedia Britannica: Syngas (description, production, and uses).
Khan Academy: Reaction of Acids with Metal Carbonates and Bicarbonates.

Instructional Materials

The teacher will teach this lesson with the aid of:

Samples of common carbonates (e.g., CaCO₃ (chalk/limestone), Na₂CO₃, NaHCO₃).
Dilute hydrochloric acid or dilute vinegar for carbonate reaction demonstration.
Glass vessels (test tubes, beakers, conical flask) and delivery tube where available.
Limewater (Ca(OH)₂ solution) for carbon dioxide test.
Charts showing properties and uses of CO and CO₂, and outline of syngas production.
Whiteboard/marker or chalkboard/chalk.

Rationale for the Lesson

Carbon oxides and carbonates are common in air, fuels, and many household and industrial materials. Understanding their properties, uses, and safety issues helps pupils to explain real-life situations like poisoning from fumes, baking, and the use of fuels and limestone products.

Prerequisite/Previous Knowledge

Pupils have learned basic ideas of elements and compounds, oxidation and reduction in simple terms, and can write simple chemical formulae and equations.

Lesson Content/Board Summary

CARBON AND ITS COMPOUNDS

Oxides of Carbon

Oxides of carbon are compounds formed when carbon combines with oxygen. The two main oxides are carbon(IV) oxide (CO₂) and carbon(II) oxide (CO).

The following are key points about carbon(IV) oxide (CO₂):

Colourless and odourless gas.
Denser than air and does not support burning (used in fire extinguishers).
Slightly soluble in water to form weak carbonic acid (H₂CO₃).
Turns limewater milky due to formation of CaCO₃.

The following are key points about carbon(II) oxide (CO):

Colourless and odourless gas.
Poisonous; combines with haemoglobin and reduces oxygen transport in blood.
Burns in air with a blue flame to form carbon(IV) oxide.
Acts as a reducing agent in some reactions (e.g., reduction of metal oxides in industry).

Comparison of Carbon(IV) Oxide and Carbon(II) Oxide

Carbon(IV) oxide and carbon(II) oxide differ in composition, properties, and uses.

The following are differences between CO₂ and CO:

Formula: CO₂ has two oxygen atoms, CO has one oxygen atom.
Combustion: CO₂ does not support burning, CO burns to form CO₂.
Safety: CO is poisonous; CO₂ is not poisonous at normal levels but can cause suffocation in confined spaces.
Common uses: CO₂ is used in fire extinguishers and carbonation of drinks; CO is used as a reducing agent and is part of synthesis gas.

Synthetic Gas (Synthesis Gas or Syngas)

Synthetic gas (syngas) is a combustible mixture mainly of carbon(II) oxide (CO) and hydrogen (H₂), sometimes containing carbon(IV) oxide and methane in small amounts.

The following are common methods of manufacture of synthetic gas:

Steam-carbon reaction (water gas): C + H₂O(g) → CO + H₂.
Steam reforming of hydrocarbons (e.g., methane): CH₄ + H₂O(g) → CO + 3H₂.
Coal gasification: carbon reacts with steam and limited oxygen to produce CO and H₂.
Water-gas shift reaction (to increase hydrogen): CO + H₂O(g) → CO₂ + H₂.

The following are uses of synthetic gas:

As a fuel gas for heating where applicable.
As a raw material for producing methanol and other chemicals.
As a feedstock in producing liquid fuels by Fischer-Tropsch process.
As a source of hydrogen for industrial processes (after shift reaction).

Trioxocarbonate(IV) Salts (Carbonates)

Trioxocarbonate(IV) salts are salts containing the carbonate ion, CO₃²⁻. Examples include sodium carbonate (Na₂CO₃) and calcium carbonate (CaCO₃).

The following are properties and reactions of trioxocarbonate(IV) salts:

Many carbonates are insoluble in water, except those of sodium, potassium, and ammonium.
Carbonates react with dilute acids to produce a salt, water, and carbon(IV) oxide gas.
Some carbonates decompose on heating to give metal oxide and carbon(IV) oxide.
Carbonates are used in glass making, cement/limestone products, detergents, and water treatment (depending on the carbonate).

Tests and Equations Related to Carbonates and Carbon(IV) Oxide

Carbon(IV) oxide can be identified using limewater.

The following are key test and equations:

General carbonate and acid reaction: MCO₃ + 2HCl → MCl₂ + H₂O + CO₂ (for a divalent metal carbonate).
Example: CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂.
Limewater test: CO₂ + Ca(OH)₂ → CaCO₃ + H₂O (milky solution).
With excess CO₂: CaCO₃ + CO₂ + H₂O → Ca(HCO₃)₂ (milkiness may disappear).

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Guided Practice, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher asks pupils to mention common situations involving carbon compounds (burning fuels, chalk/limestone, fizzy drinks, smoke from generators). The teacher introduces carbon oxides, synthetic gas, and carbonates as the lesson focus.
Pupils’ Activity: Pupils respond with examples and listen to the lesson focus.
Learning Point: Carbon forms important compounds used in daily life and industry.

Step 2: Carbon(IV) Oxide and Carbon(II) Oxide

Time: 7 minutes
Teaching Skill: Explanation and Questioning
Teacher’s Activity: The teacher explains CO₂ and CO, states their formulae, and guides pupils to list key properties and safety issues. The teacher highlights that CO is poisonous and often produced by incomplete combustion.
Pupils’ Activity: Pupils copy key points and mention at least two properties of each oxide.
Learning Point: CO₂ and CO have different properties and safety implications.

Step 3: Comparison of CO₂ and CO (Properties and Uses)

Time: 6 minutes
Teaching Skill: Discussion and Board Work
Teacher’s Activity: The teacher draws a simple comparison table on the board and guides pupils to compare the two gases in combustion behaviour, density, uses, and hazards.
Pupils’ Activity: Pupils contribute points for the comparison and copy the final notes.
Learning Point: Differences between CO₂ and CO explain their uses and risks.

Step 4: Synthetic Gas (Manufacture and Uses)

Time: 6 minutes
Teaching Skill: Explanation and Illustration
Teacher’s Activity: The teacher explains what syngas is, outlines common production methods using simple equations, and lists uses in fuels and chemical manufacture using a chart.
Pupils’ Activity: Pupils copy the definition, write at least one equation for syngas production, and list uses.
Learning Point: Syngas is an important mixture used as fuel and industrial raw material.

Step 5: Trioxocarbonate(IV) Salts (Carbonates) and Their Properties

Time: 6 minutes
Teaching Skill: Explanation and Questioning
Teacher’s Activity: The teacher presents samples or pictures of common carbonates and explains the carbonate ion, solubility pattern, and major uses. The teacher asks pupils to mention examples of carbonates found in the environment and home.
Pupils’ Activity: Pupils identify examples (chalk, limestone, washing soda, baking soda) and copy notes.
Learning Point: Carbonates are common salts with useful properties and applications.

Step 6: Demonstration of Carbonate Reaction and CO₂ Test

Time: 5 minutes
Teaching Skill: Demonstration and Observation
Teacher’s Activity: The teacher reacts a carbonate with dilute acid in a glass vessel to produce CO₂, then bubbles the gas through limewater to show milkiness. The teacher guides pupils to write the equations for the reactions observed.
Pupils’ Activity: Pupils observe the gas produced, describe the limewater change, and write the balanced equations in their notebooks.
Learning Point: Carbonates react with acids to produce carbon(IV) oxide which turns limewater milky.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define carbon(IV) oxide and carbon(II) oxide and state their formulae.
List three differences between carbon(IV) oxide and carbon(II) oxide.
State two methods of producing synthetic gas and mention two uses of synthetic gas.
Explain the reaction of a carbonate with a dilute acid and state the test for carbon(IV) oxide.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summary and Reinforcement
Teacher’s Activity: The teacher summarizes carbon oxides, syngas, and carbonate properties and reactions, then gives a short assignment on writing equations and listing differences and uses.
Pupils’ Activity: Pupils copy the summary and assignment and ask questions where necessary.
Learning Point: Carbon compounds have distinct properties, uses, and test reactions.

Lesson Keywords

Carbon(IV) oxide – CO₂, a colourless gas that does not support burning and turns limewater milky.
Carbon(II) oxide – CO, a colourless poisonous gas produced by incomplete combustion.
Synthetic gas (syngas) – a mixture mainly of CO and H₂ used as fuel and industrial raw material.
Trioxocarbonate(IV) salt – a carbonate salt containing CO₃²⁻.
Limewater test – a test for CO₂ where limewater turns milky due to CaCO₃ formation.

Differentiation

Pupils who need support will use a guided comparison table and equation templates with missing parts to complete. Pupils who learn faster will write additional balanced equations for syngas production and carbonate decomposition and provide more examples of carbonates and their uses.

Note for teachers using this lesson plan

Emphasize safety when discussing carbon(II) oxide and relate it to generator fumes and poor ventilation. Keep demonstrations small, well-ventilated, and use dilute acids. Ensure pupils write balanced equations and clear comparison points, as these are common examination demands.