Chemistry Lesson Note On Introduction to Organic Chemistry – Characteristics of Organic Compounds

Topic: Introduction to Organic Chemistry – Characteristics of Organic Compounds

Class: SS1

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Specific Objectives:

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

1. Define organic chemistry.
2. Identify characteristics of organic compounds.
3. Classify organic compounds into different groups.
4. Differentiate between organic and inorganic compounds.
5. State the importance of organic chemistry in everyday life.

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Instructional Materials:

• Samples of organic compounds (e.g., ethanol, glucose, kerosene, plastics)
• Chart showing classification of organic compounds
• Molecular model kit (if available)
• Whiteboard/Marker

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Lesson Content:

Step 1: Definition of Organic Chemistry

Organic chemistry is the branch of chemistry that deals with the study of carbon compounds (excluding carbonates, carbides, and oxides of carbon).
It focuses primarily on compounds that contain carbon and hydrogen (hydrocarbons), often with other elements like oxygen, nitrogen, sulfur, etc.

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Step 2: Characteristics of Organic Compounds

1. Presence of Carbon: Carbon is the main element in all organic compounds.
2. Covalent Bonding: Organic compounds mostly contain covalent bonds.
3. Combustibility: Most organic compounds are flammable.
4. Low Melting and Boiling Points: Many are volatile and melt/boil at relatively low temperatures.
5. Solubility: They are generally soluble in organic solvents (like ethanol, ether) and insoluble in water.
6. Isomerism: They show the phenomenon of isomerism—same molecular formula but different structures.
7. Reactivity: They undergo a wide variety of chemical reactions such as substitution, addition, and combustion.

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Step 3: Classification of Organic Compounds

Organic compounds are broadly classified into:

1. Acyclic (Open-Chain) Compounds:

   • Straight or branched chains.
   • Example: Alkanes (methane, ethane), Alcohols (ethanol).

2. Cyclic Compounds:

   • Ring-shaped structures.
   • Can be alicyclic or aromatic (benzene).

3. Saturated Compounds:

   • Contain only single bonds between carbon atoms.
   • Example: Alkanes.

4. Unsaturated Compounds:

   • Contain double or triple bonds.
   • Examples: Alkenes (double bond), Alkynes (triple bond).

5. Functional Groups:
   Organic compounds are grouped based on functional groups like:

   • Alcohols (-OH)
   • Carboxylic acids (-COOH)
   • Amines (-NH₂)
   • Aldehydes (-CHO)

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Step 4: Difference Between Organic and Inorganic Compounds

Feature	Organic Compounds	Inorganic Compounds
Main element	Carbon	Metals and non-metals
Type of bonding	Mostly covalent	Ionic or covalent
Solubility	Insoluble in water, soluble in organic solvents	Soluble in water
Thermal stability	Less stable at high temperatures	More stable
Examples	Methane, Ethanol, Glucose	NaCl, H₂SO₄, CaCO₃

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Step 5: Importance of Organic Chemistry

Organic chemistry is vital in:

• Pharmaceuticals: Production of drugs and medicines.
• Petrochemicals: Fuels like petrol, diesel, and kerosene.
• Agriculture: Fertilizers, pesticides, and insecticides.
• Polymers and Plastics: Nylon, polythene, PVC, etc.
• Food Industry: Additives, preservatives, flavorings.
• Cosmetics and Detergents.

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Evaluation:

1. Define organic chemistry.
2. List four characteristics of organic compounds.
3. Differentiate between saturated and unsaturated compounds.
4. What is a functional group? Give two examples.
5. State two differences between organic and inorganic compounds.

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Homework:

1. Classify the following compounds as saturated or unsaturated: methane, ethene, ethyne.
2. Draw the structure of ethanol and label its functional group.
3. Make a list of five materials in your home that contain organic compounds and state their use.
4. Explain why organic compounds are generally poor conductors of electricity.

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Conclusion:

Organic chemistry plays an essential role in our daily lives and industries. Understanding the nature and structure of organic compounds forms the foundation for advanced studies in chemistry and allied sciences.