Equilibria · SHS2 Chemistry

Lesson notes

Learning Objectives

Indicator: 2.1.2.LI.2

By the end of the lesson, learners can:

Describe the physical properties of acids and bases, including pH, feel, and behaviour with indicators such as litmus paper.
Describe the chemical properties of acids by predicting and writing balanced equations for their reactions with metals, bases, trioxocarbonate(IV) salts, hydrogentrioxocarbonate(IV) salts, and basic oxides.
Describe the chemical properties of bases by predicting and writing balanced equations for their reactions with acidic oxides, ammonium salts, and acids.
Demonstrate safe laboratory practice by carrying out experiments on acids and bases in groups and accurately recording observations.

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Curriculum details

Strand: Physical Chemistry (Strand 1)
Sub-strand: Equilibria (1.2)
Content standard: 2.1.2.CS.2 - Demonstrate knowledge and understanding of the concepts and properties of acids and bases to classify substances as well as determine concentration of analysis through titration. 2.1.2.LO.1 Explain that dynamic equilibrium is attained when the rates of the forward and backward reactions are equal and this principle has industrial applications. 2.1.2.LO.2 Apply your knowledge in acids and bases to classify and describe substances as acids and bases as well as determine the concentration of analyte through titration.
Indicator: 2.1.2.LI.2 - Describe the physical and chemical properties of acids and bases.
Suggested placement: Semester 1, Week 18 (Week 18 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. 71

Exemplars (from the NaCCA curriculum)

Exploratory Learning: In small mixed ability groups,
- Explore using virtual laboratory or simulation or simple activities, the physical properties of acids and bases under the following headings: pH, feel, behaviour in indicators (including litmus paper)
Note: No chemicals should be tasted in the laboratory.
Experiential Learning:
- Undertake experiments on acids such as: a) Reaction with metals like Zn, Fe and Mg. b) Reaction with bases (Neutralization). c) Reaction with trioxocarbonate(IV), (CO ) or hydrogentrioxocarbonate(IV), (HCO ) 32- 3- d) Reaction with basic oxides.
- Undertake experiments on bases such as: a. Reaction with acidic oxides. b. Reaction with ammonium salts to liberate ammonia gas
c. Reaction with acids.
Talk for Learning: Discuss application of neutralization in treating insect bites, stomach indigestion, treating soil and lake acidity.
Teaching and Learning Materials:
- * Worksheets with illustrative examples of Arrhenius,
- Bronsted-Lowry and Lewis acids and bases for
- Learners to identify * Fruits * Vegetables * Common acids (HCl, HNO , H SO CH COOH,
- H CO , 2 3 * Bases * Universal indicator with pH colour chart * Litmus papers * Ammonium compound (e.g., ammonium chloride) * Bases: NaOH(aq), KOH(aq), Ca(OH) , NH * Zinc chips, iron filings, magnesium ribbon * pH meter * A simple electric circuit with electric bulb/ lamp, beakers, wire, key/switch
- 3 2 4, 3
- 2 3
- * Mixture of Na CO and * Methyl orange and phenolphthalein
- Burette * Pipette * Conical flask * Droppers * Retort stand and clamp * Pipette filler * White tile * Wash bottle with distilled * Calculator
- NaHCO ) 2 3 3 indicators
- water
Assessment (2.1.2.AS.2). The document marks these depth-of-knowledge levels for this indicator: Level 2 Skills of conceptual understanding.