The development and use of materials for specific purposes is an important human endeavour. In this unit students investigate the chemical structures and properties of a range of materials, including covalent compounds, metals, ionic compounds and polymers. They are introduced to ways that chemical quantities are measured. They consider how manufacturing innovations lead to more sustainable products being produced for society through the use of renewable raw materials and a transition from a linear economy towards a circular economy.
Students conduct practical investigations involving the reactivity series of metals, separation of mixtures by chromatography, use of precipitation reactions to identify ionic compounds, determination of empirical formulas, and synthesis of polymers.
Throughout this unit students use chemistry terminology including symbols, formulas, chemical nomenclature and equations to represent and explain observations and data from their own investigations and to evaluate the chemistry-based claims of others.
A student-directed research investigation into the sustainable production or use of a selected material is to be undertaken in Area of Study 3. The investigation explores how sustainability factors such as green chemistry principles and the transition to a circular economy are considered in the production of materials to ensure minimum toxicity and impacts on human health and the environment. The investigation draws on key knowledge and key science skills from Area of Study 1 and/or Area of Study 2.

Area of Study 1

How do the chemical structures of materials explain their properties and reactions? 

In this area of study students focus on elements as the building blocks of useful materials. They investigate the structures, properties and reactions of carbon compounds, metals and ionic compounds, and use chromatography to separate the components of mixtures. They use metal recycling as a context to explore the transition in manufacturing processes from a linear economy to a circular economy.
The selection of learning contexts should allow students to develop practical techniques to investigate the properties and reactions of various materials. Students develop their skills in the use of scientific equipment and apparatus. Students may conduct flame tests to identify elements in the periodic table. They may model covalent, metallic and ionic structures using simple ball-and-stick models and may use computer simulations of the three-dimensional representations of molecules and lattices to better understand structures. They use solubility tables to experimentally identify unknown ions in solution. They respond to challenges such as developing their own reactivity series by reacting samples of metals with acids, oxygen and water.

Outcome 1
On completion of this unit the student should be able to explain how elements form carbon compounds, metallic lattices and ionic compounds, experimentally investigate and model the properties of different materials, and use chromatography to separate the components of mixtures.
To achieve this outcome the student will draw on key knowledge outlined in Area of Study 1 and the related key science skills on pages 11 and 12 of the study design.

Elements and the periodic table

• the definitions of elements, isotopes and ions, including appropriate notation: atomic number; mass number; and number of protons, neutrons and electrons
• the periodic table as an organisational tool to identify patterns and trends in, and relationships between, the structures (including shell and subshell electronic configurations and atomic radii) and properties (including electronegativity, first ionisation energy, metallic and non-metallic character and reactivity) of elements
• critical elements (for example, helium, phosphorus, rare-earth elements and post-transition metals and metalloids) and the importance of recycling processes for element recovery

Reactivity of metals

Introduce the concept of core charge before discussing trends in the periodic table.

Relative atomic mass (A_r) as the weighted average of the isotopic masses.

Flame testing

Covalent substances

• the use of Lewis(electron dot) structures), structural formulas and molecular formulas to model the following molecules: hydrogen, oxygen, chlorine, nitrogen, hydrogen chloride, carbon dioxide, water, ammonia, methane, ethane and ethene
• shapes of molecules (linear, bent, pyramidal, and tetrahedral, excluding bond angles) as determined by the repulsion of electron pairs according to valence shell electron pair repulsion (VSEPR) theory
• polar and non-polar character with reference to the shape of the molecule
• the relative strengths of intramolecular bonding intermolecular forces and (covalent bonding) and (dispersion forces, dipole-dipole attraction and hydrogen bonding)
• physical properties of molecular substances (including melting points and boiling points and non-conduction of electricity) with reference to their structure and bonding
• the structure and bonding of diamond and graphite that explain their properties (including heat conductivity and electrical conductivity and hardness) and their suitability for diverse applications

Predicting the shape of a molecule given its formula.

Covalency

Symmetrical molecules

Asymmetrical molecules

Assignment on molecules Solutions

Worksheet 1 Solutions - molecular shape, intermolecular and intramolecular bonding.

Reactions of metals

• the common properties of metals (lustre, malleability, ductility, melting point, heat conductivity and electrical conductivity) with reference to the nature of metallic bonding and the existence of metallic crystals
• experimental determination of a reactivity series of metals based on their relative ability to undergo oxidation with water, acids and oxygen
• metal recycling as an example of a circular economy where metal is mined, refined, made into a product, used, disposed of via recycling and then reprocessed as the same original product or repurposed as a new product

Reactivity of group 1 metals

Demonstration of an alloy.

Annealing

Experiment -copper processing.

Extraction of copper from an ore.

Reactions of ionic compounds

• the common properties of ionic compounds (brittleness, hardness, melting point, difference in electrical conductivity in solid and molten liquid states), with reference to the nature of ionic bonding and crystal structure
• deduction of the formula and name of an ionic compound from its component ions, including polyatomic ions (NH₄⁺, OH^-, NO₃^-, HCO₃^2-, CO₃^2-, SO₄^2- and PO₄^3-)
• the formation of ionic compounds through the transfer of electrons from metals to non-metals, and the writing of ionic compound formulas, including those containing polyatomic ions and transition metal ions
• the use of solubility tables to predict and identify precipitation reactions between ions in solution, represented by balanced full and ionic equations including the state symbols: (s), (l), (aq) and (g)

Lesson 4 Solutions - chemical and ionic equations

Derive the chemical formula of ionic compounds given the valencies of ions and be able to name the compounds given their formula.

Students may like a more visual approach to deriving ionic formulae.

Naming ionic compounds

Precipitates

- precipitation worksheet
- naming the precipitate
- writing equations
- experiment (equations)

-ionic formulae
-ionic formulae exercise
-naming ionic formulae

Exercises - Predicting precipitates and writing chemical and ionic equations.

Precipitation experiment

Separation and identification of the components of mixtures

• polar and non-polar character with reference to the solubility of polar solutes dissolving in polar solvents, and non-polar solutes dissolving in non-polar solvents
• experimental application of chromatography as a technique to determine the composition and purity of different types of substances, including calculation of Rf values

Area of Study 2

How are materials quantified and classified?

In this area of study students focus on the measurement of quantities in chemistry and the structures and properties of organic compounds, including polymers.

On completion of this unit the student should be able to calculate mole quantities, use systematic nomenclature to name organic compounds, explain how polymers can be designed for a purpose, and evaluate the consequences for human health and the environment of the production of organic materials and polymers.
To achieve this outcome the student will draw on key knowledge outlined in Area of Study 2 and the related key science skills on pages 11 and 12 of the study design.

Quantifying atoms and compounds

• the relative isotopic masses of isotopes of elements and their values on the scale in which the relative isotopic mass of the carbon-12 isotope is assigned a value of 12 exactly
• determination of the relative atomic mass of an element using mass spectrometry (details of instrument not required)
• Avogadro’s constant as the number
  6.02 × 10²³ indicating the number of atoms or molecules in a mole of any substance; determination of the amount, in moles, of atoms (or molecules) in a pure sample of known mass
• determination of the molar mass of compounds, the percentage composition by mass of covalent compounds, and the empirical and molecular formula of a compound from its percentage composition by mass

Empirical formula
Quiz 1 Solution Empirical formulae
Quiz 2 Solution Empirical formulae
Quiz 3 Solution Empirical formulae
Quiz 4 Solution Empirical to molecular formulae

Empirical formula test Solutions

Revision 1 Solutions - ionic and metallic bonding and mole calculations.

-numbers to mol exercises
-mass to mol exercises
-mol to mass exercises
-numbers to mass exercises
-mixed exercises
-mol ratio (empirical formula)
-molecules to atoms
-formula mass and the mol
-atomic volume and the mol

Empirical formula of :
hydrated copper sulfate,
magnesium oxide

Calculating atomic radii.

Determination of the molecular mass of a compound (CO₂)

Families of organic compounds

• the grouping of hydrocarbon compounds into families (alkanes, haloalkanes, alkenes, alcohols, carboxylic acids based upon similarities in their physical and chemical properties, including general formulas and general uses based on their properties
• representations of organic compounds (structural formulas, semi-structural formulas) and naming according to the International Union of Pure and Applied Chemistry (IUPAC) systematic nomenclature (limited to non-cyclic compounds up to C8, and structural isomers up to C5)
• plant-based biomass as an alternative renewable source of organic chemicals (for example, solvents, pharmaceuticals, adhesives, dyes and paints) traditionally derived from fossil fuels
• materials and products used in everyday life that are made from organic compounds (for example, synthetic fabrics, foods, natural medicines, pesticides, cosmetics, organic solvents, car parts, artificial hearts), the benefits of those products for society, and the health and/or environmental hazards they pose

Quiz 1 Solutions Naming organic compounds

Test Solutions (Naming organic compounds, structural, semistructural formulae,esters)

Quiz 2 Solutions (determination of molecular formula from empricial formula)

Quiz 3 Solutions (Nmaing organic compounds)

Quiz 4 Solutions - (naming organic compounds with more than one functional group)

Exercise (converting structutral into semi-structural formulae).

Polymers and society

Video introduction to polymers.

• the differences between addition and condensation reactions as processes for producing natural and manufactured polymers from monomers
• the formation of addition polymers by the polymerisation of alkene monomers
• the distinction between linear (thermoplastic) and cross-linked (thermosetting) addition polymers with reference to structure and properties
• the features of linear addition polymers designed for a particular purpose, including the selection of a suitable monomer (structure and properties), chain length and degree of branching
• the categorisation of different plastics as fossil fuel based (HDPE, PVC, LDPE, PP, PS) and as bioplastics (PLA, Bio-PE, Bio-PP); plastic recycling (mechanical, chemical, organic), compostability, circularity and renewability of raw ingredients
• innovations in polymer manufacture using condensation reactions, and the breakdown of polymers using hydrolysis reactions, contributing to the transition from a linear economy towards a circular economy

Plastics

Chemistry of plastics

Making of thermosetting plastic.

Repurposing PLA

Revision Unit 1(a) Solution

Revision Unit 1(b) Solution

Revision Unit 1(c) Solution

Revision Unit 1(d) Solution

Area of Study 3
How can chemical principles be applied to create a more sustainable future
Knowledge of the structure and properties of matter has developed over time through scientific and technological research, leading to the production of a range of useful chemicals, materials and products for society. Chemists today, through sustainable practices, seek to improve the efficiency with which natural resources are used to meet human needs for chemical products and services. Chemists also learn from Aboriginal and Torres Strait Islander peoples about the ways that they sustainably modify and process raw materials using techniques developed over millennia. Sustainability requires innovation in designing and discovering new chemicals, production processes and product management systems that will provide increased yield or performance at a lower cost while meeting the goals of protecting and enhancing human health and the environment. In this area of study students undertake an investigation involving the selection and evaluation of a recent discovery, innovation, advance, case study, issue or challenge linked to the knowledge and skills developed in Unit 1 Area of Study 1 and/or Area of Study 2, including consideration of sustainability concepts (green chemistry principles, sustainable development and the transition towards a circular economy). Examples of investigation topics and possible research questions are provided below.

Students may select a research question related to the investigation topics included below or, in conjunction with their teacher, develop their own research question related to Unit 1 Area of Study 1 and/or Area of Study 2. Possible starting points when developing a research question may include visiting a chemical laboratory, local chemical manufacturer or industrial plant; announcements of recent materials science research findings; an interview with an expert involved in materials science or sustainability; an expert’s published point of view; a public concern about an issue related to the production of a chemical or material; ‘green field’ research leading to new technologies; changes in government funding or policy or new government initiatives, such as incentives promoting the transition from a linear economy to a circular economy; case studies related to how Aboriginal and Torres Strait Islander peoples process natural materials for particular purposes; a TED talk; a YouTube presentation; or an article from a scientific publication.
Students apply critical and creative thinking and science inquiry skills to prepare a communication to explain the relevant chemical concepts associated with their investigation, critically examine the information and data available to answer the research question, and identify the sociocultural, economic, political, legal and ethical implications of the selected investigation in terms of sustainability.

Investigation 1: Endangered elements in the periodic table
Today’s chemists are involved in many branches of chemistry, covering all 118 elements in the periodic table. Some of these elements are now considered to be critical and endangered, particularly due to the prevalence of modern technologies that rely on many different scarce minerals. It has been estimated that
44 elements will soon be, or are already, facing supply limitations, making a future of continuing technological advancement uncertain.

Questions that may be explored in this investigation include:

• Which chemicals are used in the manufacture of fireworks, what is the environmental impact of the combustion of these chemicals to produce the colourful effects seen in fireworks displays, and what alternatives are available?
• Based on their usefulness for society, how would you compare the value of lanthanoids and actinoids with the value of other metal groups in the periodic table?
• Why is helium classified as a critical and endangered element, and how can it be saved given that its atmospheric recovery is almost impossible?
• How is indium mined and used in the manufacture of products such as LCD screen televisions and computer monitors, mobile phones or photovoltaic panels, and what alternatives are available if indium becomes scarce?
• How do the properties of the metalloids (such as germanium, antimony, tellurium) differ so much to their neighbours on the periodic table, and how have these properties made them highly important for society and consequentially scarce in supply?
• How are precious metals from electronic waste (e-waste) recycled and what are the environmental and economic benefits of these recovery processes?

Investigation 2: Producing and using ‘greener’ polymers
Both natural and synthetic polymers play an important role in everyday life. The cells in animals and plants are built of, and metabolise, natural polymers. Proteins and carbohydrates in our food are both polymers. Synthetic polymers are used for a myriad of purposes in everyday life but may present challenges in terms
of the by-products resulting from their manufacture or breakdown, and their persistence in the environment. The sustainability of polymers can be considered in terms of whether these plastics can be avoided by using different products or activities, reduced through design, or replaced by different materials.

Questions that may be explored in this investigation include:

• What are plant-based biopolymers and what are the impacts of their production on the environment?
• How do biodegradable and degradable polymers, compostable polymers and recyclable polymers differ in structure, production and environmental impacts?
• What is the difference between micropolymers and nanopolymers, and how are used plastic materials and litter managed and repurposed?
• Is the recycling of packaging products containing aluminium more sustainable than LDPE polymer-based packaging products?
• Why is the sale of plastic water bottles and single-use plastics banned in many countries?
• How do animal proteins compare with non-animal proteins for different applications, such as meat substitutes and non-animal leather?
• How do the chemical structures of elastomers differ from the structures of thermosetting and thermoplastic polymers, and what are the implications of the production of elastomers for society?
• What impact does the vulcanisation of rubber have on the environment and the communities where rubber is sourced and produced?
• What are the risks and benefits to the environment of the manufacturing, production and application of synthetic fibres for the textile industry (for example, synthetic grass, active wear, shoes and single-use plastics such as takeaway cups, containers, and electrical and electronic products such as mobile phone cords and USB flash drives)?

Investigation topic 3: The chemistry of Aboriginal and Torres Strait Islander peoples’ practices
Throughout history, people all over the world have hypothesised, experimented, made empirical observations, gathered evidence, recognised patterns, verified through repetition, and made inferences and predictions to help them to make sense of the world around them and their place within it. Recent research and discussion have confirmed many Aboriginal and Torres Strait Islander groups use the environment and its resources to solve the challenges they face in the different Australian climates in ways that are more sustainable than similar materials produced in Western society. Their solutions can be explained by a variety of organic and non-organic chemical processes.

Questions that may be explored in this investigation include:

• Which plants are important to Aboriginal and Torres Strait Islander peoples for their medicinal properties, how are the plants processed before they are used, and what are the active ingredients (for example, the terpineols, cineoles and pinenes as the active constituents of tea trees and eucalyptus resin)?

• What are the chemical processes that occur when Aboriginal and Torres Strait Islander peoples detoxify poisonous food items: for example, the preparation of nardoo as a food source by heating, and the detoxification of cycad seeds through the removal of cycasins?
• How do Aboriginal and Torres Islander peoples utilise animal fats, calcination and plant pigments to vary the properties of the paints they make, and how does this compare to Western paint production processes and materials?
• How do binders and fixatives work to allow Aboriginal and Torres Islander peoples’ paintings to be preserved for thousands of years?
• How do Aboriginal and Torres Islander peoples’ glue formulations parallel the use of modern epoxy resins, and how sustainable are the chemical processes involved in producing these materials?
• How are plant-based toxins such as saponins used in Aboriginal and Torres Strait Islander peoples’ fishing practices, and how is this similar to other First Nation Peoples’ fishing practices around the world?
• Kakadu plums have long been a component of Aboriginal and Torres Islander Peoples diets. What active ingredients do they contain that may make them a ‘super food’?

Investigation 4: The sustainability of a commercial product or material
In Australia, new materials that are useful for society tend to be produced through a linear economy in which products are purchased, used and then thrown away. Increasingly, manufacturing companies are moving towards a circular economy, which seeks to reduce the environmental impacts of production and consumption while enabling economic growth through more productive use of natural resources and creation of less waste.

Research questions that may be explored in this investigation include:

• What is ‘green steel’ and what are the implications of its production for human health and the environment?
• Research a metal mined in Australia: for example, gold, copper or lithium. How is the metal processed and what are its useful properties? To what extent has the metal production and use moved towards a circular economy over the last decade? What innovations have led to the production of the metal being more sustainable over time?
• Select a commercial product that is available in different formulations: for example, vinegar (fermented, synthetic); salt (river salt, sea salt, iodised salt, Himalayan salt); cleaning products (soaps and detergents); oil (fish oil, coconut oil, olive oil); or milk (whole milk, skim milk, low-fat milk, A2 milk, plant milks such as almond, soy and coconut). What ingredients are in the product? How do the ingredients compare in the different product formulations? How is the product made? To what extent does the production of the product involve a linear economy or a circular economy? How does the production and use of the product impact human health and the environment?
• Select a product whose composition has changed over time: for example, hair comb (tortoiseshell to polymer); dental fillings (from silver amalgam and gold to porcelain and composite resin fillings); contact lenses (glass to polymers); paints (lead-based to oil-based and water-based); and tennis racquet strings (from cat gut to nylon and polyester). How have the properties and efficacies of the products changed over time? To what extent have the manufacturing processes become ‘greener’?
• Examine the life cycle of a new product or material: for example, unbreakable glass inspired by seashells; new nanomaterials for the treatment of skin infections; and ultra-thin self-healing polymers to make water-resistant coatings. What is the relationship between the properties, structure and the nature and strength of the chemical bonding in the product or material? What are the raw materials used to make the product or material? How is the product or material manufactured? How are the by-products of production treated and managed? Is the product recyclable? Can any wastes during production or at the end of the product’s use be repurposed into a useful product or material?