Organic Functional Groups · SHS2 Chemistry

Lesson notes

Learning Objectives

Indicator: 2.3.2.LI.2 - Explain the nomenclature, structure, properties of alkenes and alkynes.

By the end of the lesson, learners can:

Generate the molecular formulae and structures of the first six alkenes (ethene to hexene) and first six alkynes (ethyne to hexyne) using their general molecular formulae.
Apply IUPAC rules to name straight-chain and branched-chain alkenes and alkynes up to six carbon atoms, including positional isomers.
Distinguish between alkenes and alkanes experimentally using bromine water, and explain the chemical basis for the observation.
Write balanced chemical equations for the reactions of alkenes with hydrogen, halogens, steam, hydrogen halides, and KMnO₄, applying Markovnikov’s rule for unsymmetrical alkenes.
Describe the laboratory preparation of ethyne, explain the acidity of terminal alkynes, and outline the use of ethyne in welding.

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Curriculum details

Strand: Chemistry of Carbon Compounds (Strand 3)
Sub-strand: Organic Functional Groups (3.2)
Content standard: 2.3.2.CS.1 - Demonstrate knowledge and understanding of source, structure, nomenclature, properties and uses of organic compounds as well as the characteristic test for their functional groups. 2.3.2.LO.1 Explain the source, structure, nomenclature, properties, uses of the various classes of organic compounds and the test for their functional groups.
Indicator: 2.3.2.LI.2 - Explain the nomenclature, structure, properties of alkenes and alkynes.
Suggested placement: Semester 2, Week 15 (Week 35 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: NaCCA curriculum document, p. 87

Exemplars (from the NaCCA curriculum)

Collaborative Learning Approach: Using think-pair-share,
- Generate the formulae and structure of the first six alkenes series using their general molecular formula.
Activity-Based Learning
- Model each isomer of alkene (C4 and C5).
- Apply IUPAC rules to name alkenes up to C6 (straight chain and branched chain).
- Design a mind map to show the sources, the laboratory preparation and physical properties of alkenes
- Write chemical equations to illustrate the reactions of symmetrical and unsymmetrical alkenes with: a. Hydrogen b. Halogens c. Steam d. Hydrogen halides e. KMnO 4 Note: Use Markornikov's rule for the unsymmetrical alkenes.
Experiential Learning: Distinguish between alkanes and alkenes using bromine water or bromine in tetrachloromethane.
Initiating Talk for Learning:
- Outline the economic importance of the reactions of alkenes (production of margarine and alcohol).
- Watch video to reinforce the concepts taught.
Collaborative Learning Approach:
- Generate the formulae and structure of the first six alkynes in their homologous series using their general molecular formula.
- Determine structure of the isomers of C4 and C5
- Discuss the acidity of terminal alkynes and distinguish them chemically from non-terminal alkynes.
- Describe the preparation of ethyne,
- Write chemical equations to illustrate reactions of terminal and non-terminal reaction with a) Hydrogen, b) Halogen c) Hydrogen halide
- Discuss the use of ethyne in welding (combustion reactions of alkynes)
- Watching video to reinforce the concepts taught.
Teaching and Learning Materials:
- * Molecular models * Video of greenhouse effect, toxicity of CO, acid rain * Worksheets with task on naming, isomer, and properties * Worksheets with tasks on naming, isomers, properties, uses of alkenes * Video of preparation of ethyne * Worksheets with tasks on naming, isomers, properties, uses of alkynes * Materials to design alcohol breath analyser Kit for esterification reactions * Na, NaHCO , PCl , C H OH, LiAlH * Worksheets on reactions of benzene
- WEBSITE * Virtual lab/video on laboratory and reactions of alkanoic acids * Virtual lab/video on laboratory and industrial preparation of alcohol
- 3 5 2 5
- YEAR THREE
- 4
- * Virtual labs on preparation of
- Virtual lab on preparation of
- Videos on the topic:
- CHARTS * Charts on homologous series column * Charts on uses of alkynes * Charts on uses of alkenes * Chart on uses of benzene
- Chart on classes of alcohols,
- Chart on uses of alkanoic acids * Chart on molecular orbital
- alkene, test for alkenes alkynes khanacademy.org
- of alkanes, fractionating
- uses of alkanols
- theory of benzene
Assessment (2.3.2.AS.2). The document marks these depth-of-knowledge levels for this indicator: Level 3 Strategic reasoning.