SHS3 Chemistry · Semester 1, Week 15
Equilibria
Lesson notes
Learning Objectives
Indicator: 3.1.2.LI.3 - Explain how redox is used to produce electricity in storage and fuel cells.
By the end of the lesson, learners can:
- Explain how a potential difference is developed between an electrode and the aqueous solution of its ions, and list the factors that affect the value of this electrode potential.
- Describe the standard hydrogen electrode (SHE) and explain why it is used as a reference for measuring electrode potentials.
- Construct and represent voltaic cells using standard notation (line notation) and calculate the standard cell potential (E°cell) by combining two half-cells.
- Write and balance the half-equations and overall equations for lead-acid, alkaline, lithium-ion, and nickel-cadmium storage cells.
- Explain how hydrogen fuel cells produce electricity, write their half and overall equations, and evaluate their advantages over diesel-powered vehicles.
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Sign in with phone numberCurriculum details
- Strand
- Physical Chemistry (Strand 1)
- Sub-strand
- Equilibria (1.2)
- Content standard
- 3.1.2.CS.4 - Demonstrate knowledge and understanding of redox and apply its principles to electrochemical cells as well as their importance in everyday life. 3.1.2.LO.1 Use the knowledge in pH to distinguish between solutions that are acidic, neutral or basic. 5 Gender Equality and Social Inclusion 6 Socio-Emotional Learning 3.1.2.LO.2 Use your knowledge and understanding of concepts in hydration and hydrolysis to determine the types of salts. 3.1.2.LO.3 Use the understanding of hydrolysis of salts to decide on suitable indicator as well as plot and interpret titration curves. 3.1.2.LO.4 Describe oxidation and reduction reactions and apply their principles to electrochemical cells as well as their importance in everyday life.
- Indicator
- 3.1.2.LI.3 - Explain how redox is used to produce electricity in storage and fuel cells.
- Suggested placement
-
Semester 1, Week 15
(Week 15 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. 100
Exemplars (from the NaCCA curriculum)
Collaborative learning - In gender-based groups where applicable, describe how a potential is developed between an electrode placed in aqueous solution of its ions and discuss the factors that affect its value: a. Nature of electrode b. Temperature of electrolyte c. Concentration of electrolyte d. Pressure of gas species - Explain why it is impossible to obtain an absolute electrode potential for a single half - cell. - Describe the standard hydrogen electrode. - Describe how to measure standard electrode potentials relative to the standard hydrogen electrode. - Describe how standard electrode potentials are used to construct and represent voltaic cells by writing and drawing of: a. Metals or non-metals in contact with their ions in aqueous solution b. Ions of the same element in different oxidation states - Use video or simulation to illustrate and explain the operation of a voltaic cell Problem Solving Approach: - Calculate a standard cell potential by combining two half-cells. - Predict the feasibility of a reaction using: a. Standard cell potentials b. Gibbs free energy (∆G =-nFE ) cell Note: Limitations of predictions made using standard cell potentials in terms of kinetic energy and concentrations are not required. Exploratory Learning: - Design and perform experiment to determine emf of voltaic cell. - Apply the principles of electrode potentials to modern storage cells: a. Lead-acid battery (wet cell) b. Alkaline cell (dry) c. Lithium-ion battery. d. Nickel-cadmium battery. e. Fuel cells - Write their simple half and overall equations Digital Learning: Watch videos on storage and fuel cells and how scientists in car industry are developing fuel cell vehicles fuelled by: a. Hydrogen gas b. Hydrogen-rich fuels and their advantages over conventional diesel powdered vehicles (STEM) Teaching and Learning Materials: - * Test tubes in a rack * Strips of copper foil * Strips of zinc foil * * 0.1M potassium bromide - Strip of silver wire * * ICT tools Emery paper * * Calculator 0.5 M copper sulphate solution * 0.5 M zinc sulphate solution - * 0.1 M silver nitrate solution * 50 ml Burettes * 25 ml pipettes * 250 ml conical flasks * 100 ml beakers * White tiles - * Retort stands * solution - KMnO 4 * * 0.02M potassium Iron (II) solution * manganate (VII) Iodine solution * Potassium iodide * Na S O 2 2 3 * Starch * * Electrolysis cell Test tubes * Test tube rack - * Copper powder * Zinc powder * * Clamps and stands Bromine water * * Cover slides 0.1 M potassium iodide solution * 0.1 M potassium chloride solution - * 0.1 M Iron (III) chloride - * Power pack - * Connecting wires and clips - * Wooden splint * Droppers * 1 M tetraoxosulphate (VI) acid * 1 M sodium chloride solution - * 1 M copper(II) chloride * Identical fresh nails * Test tube in test tube racks * Stoppers * Spatula * PH sensor * Temperature sensor * Stands and clamps - * Calcium chloride * Oil * Iron coated with zinc * Iron coated with tin * Iron filings * Salt Assessment (3.1.2.AS.3). The document marks these depth-of-knowledge levels for this indicator: Level 4 Extended critical thinking and reasoning.