Chemistry Unit 3: How can design and innovation help to optimise chemical processes?

Prerequisites

Chemistry Unit 1 & 2. Mathematical Methods is strongly recommended.

Course Description

The global demand for energy and materials is increasing with world population growth. In this unit students investigate the chemical production of energy and materials. They explore how innovation, design and sustainability principles and concepts can be applied to produce energy and materials while minimising possible harmful effects of production on human health and the environment.

Students analyse and compare different fuels as energy sources for society, with reference to the energy transformations and chemical reactions involved, energy efficiencies, environmental impacts and potential applications. They explore food in the context of supplying energy in living systems. The purpose, design and operating principles of galvanic cells, fuel cells, rechargeable cells and electrolytic cells are considered when evaluating their suitability for supplying society’s needs for energy and materials. They evaluate chemical processes with reference to factors that influence their reaction rates and extent. They investigate how the rate of a reaction can be controlled so that it occurs at the optimum rate while avoiding unwanted side reactions and by-products. Students conduct practical investigations involving thermochemistry, redox reactions, electrochemical cells, reaction rates and equilibrium systems.

Areas of Study

What are the current and future options for supplying energy?

In this area of study students focus on analysing and comparing a range of fossil fuels and biofuels as energy sources for society, and carbohydrates, proteins and lipids as fuel sources for the body. They write balanced thermochemical equations for the combustion of various fuels. The amounts of energy and gases produced in combustion reactions are quantified using stoichiometry. They explore how energy can be sustainably produced from chemicals to meet the needs of society while minimising negative impacts on the environment.

The selection of learning contexts should allow students to develop practical techniques to investigate how energy from fuels can be obtained and measured, and to determine the efficiency of different fuels and electrochemical cells as sources of energy. Students develop their skills in the use of scientific equipment and apparatus. They may measure energy released in combustion reactions through quantitative calorimetry experiments and may compare amounts of energy released in different fuels, such as methane, alcohols, waxes and foods. They design, construct and test galvanic and fuel cells, and account for differences between experimental findings and predictions made by using the electrochemical series. Students may work collaboratively to construct electrochemical half-cells and experiment with different combinations of half-cells to develop their own electrochemical series. Students respond to challenges such as designing an electrochemical cell that generates the most energy under laboratory conditions using a limited range of supplied chemicals and materials.

How can the rate and yield of chemical reactions be optimised?

In this area of study, students explore the factors that affect the rate and yield of equilibrium and electrolytic reactions involved in producing important materials for society. Reactants and products in chemical reactions are treated qualitatively through the application of Le Chatelier’s principle and quantified using equilibrium expressions, reaction quotients and Faraday’s Laws. Students explore the sustainability of different options for producing useful materials for society.

The selection of learning contexts should allow students to develop practical techniques to investigate equilibrium and electrolysis. Students develop their skills in the use of scientific equipment and apparatus. They investigate reaction rates including the measurement of mass, gas volumes and time. They use an equilibrium system, such as iron(III) thiocyanate, to predict and test the effect of different changes to the system. They investigate the effect of catalysts on reaction rates, such as comparing the rate of decomposition of hydrogen peroxide using organic and inorganic catalysts. Students explore the application of electrolysis in the manufacture of useful products through experiments such as electroplating and anodising. They model and explain the operation of secondary cells: for example, those in portable devices such as laptops or cell phones. Students respond to challenges such as predicting and testing the optimum conditions under which a selected reaction can produce the highest product yield.

Assessment

Outcomes	Assessment Tasks	Marks Allocated
	(school-assessed coursework)
Compare fuels quantitatively with reference to combustion products and energy outputs, apply knowledge of the electrochemical series to design, construct and test primary cells and fuel cells, and evaluate the sustainability of electrochemical cells in producing energy for society..	For each outcome, one task selected from: comparison and evaluation of chemical concepts, methodologies and methods, and findings from at least two practical activities analysis and evaluation of primary and/or secondary data, including identified assumptions or data limitations, and conclusions problem-solving, including calculations, using chemistry concepts and skills applied to real-world contexts analysis and evaluation of a chemical innovation, research study, case study, socio-scientific issue, or media communication. Each task type can be selected only once across Units 3 and 4. At least one of the four tasks should include reference to sustainability.	40
Experimentally analyse chemical systems to predict how the rate and extent of chemical reactions can be optimised, explain how electrolysis is involved in the production of chemicals, and evaluate the sustainability of electrolytic processes in producing useful materials for society.		40
Total Marks		80

Overall Final Assessment