Chemistry Unit 2: How do chemical reactions shape the natural world?

Prerequisites

Students are advised to complete the Year 10 Chemistry course and Chemistry Unit 1 before undertaking Chemistry Unit 2. Mathematical Methods is strongly recommended.

Course Description

Society is dependent on the work of chemists to analyse the materials and products in everyday use. In this unit students analyse and compare different substances dissolved in water and the gases that may be produced in chemical reactions. They explore applications of acid-base and redox reactions in society.

Students conduct practical investigations involving the specific heat capacity of water, acid-base and redox reactions, solubility, molar volume of a gas, volumetric analysis, and the use of a calibration curve.

Throughout the 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-adapted or student-designed scientific investigation is undertaken in Area of Study 3. The investigation involves the generation of primary data and is related to the production of gases, acid-base or redox reactions, or the analysis of substances in water. It draws on the key science skills and key knowledge from Unit 2 Area of Study 1 and/or Area of Study 2.

Areas of Study

How Do Chemicals Interact with Water?

In this area of study students focus on understanding the properties of water and investigating acid-base and redox reactions. They explore water’s properties, including its density, specific heat capacity and latent heat of vaporisation. They write equations for acid-base and redox reactions, and apply concepts including pH as a measure of acidity. They explore applications of acid-base reactions and redox reactions in society.

Key Knowledge:

Water as a unique chemical
Acid-base (proton transfer) reactions
Redox (electron transfer) reactions

How are chemicals measured and analysed?

In this area of study students focus on the analysis and quantification of chemical reactions involving acids, bases, salts and gases. They measure the solubility of substances in water, explore the relationship between solubility and temperature using solubility curves, and learn to predict when a solute will dissolve or crystallise out of solution. They quantify amounts in chemistry using volumetric analysis, application of the ideal gas equation, stoichiometry and calibration curves.

The selection of learning contexts should allow students to develop practical techniques to investigate substances that may be dissolved in water or found in soils, particularly salts, acids and bases, as well as gases. Students develop their skills in the use of scientific equipment and apparatus. They use precipitation reactions to purify water: for example, by using iron or aluminium compounds to precipitate and remove phosphorus from wastewater. They perform acid-base titrations, such as comparing the ethanoic acid concentrations of vinegar, mayonnaise and tomato sauce. They construct calibration curves to analyse unknown concentrations of substances, such as the amount of nitrates or phosphates in water or soil samples. Students respond to challenges such as determining the set of standards required in setting up a calibration curve in colorimetry. 

Key Knowledge

Measuring solubility and concentration.
Analysis for acids and bases.
Measuring gases
Analysis for salts.

How do quantitative scientific investigations develop our understanding of chemical reactions?

In this area of study students adapt or design and then conduct a scientific investigation related to chemical equations and/or analysis, which must include the generation of primary data. They develop a research question related to the production of gases, acid-base or redox reactions or the analysis of substances in water, and adapt or design and then conduct a scientific investigation to generate appropriate quantitative data. Students organise and interpret the data and reach a conclusion in response to their research question.

Research questions may relate to different scientific methodologies. Pattern seeking may be utilised in investigating questions such as ‘Is there a relationship between salinity concentration and the rate of rusting of iron?’. Controlled experiments may be designed to investigate questions such as ‘Why is isopropyl alcohol measured as %(v/v) while chlorine bleach is measured in ppm, and what concentrations of isopropyl alcohol and chlorine bleach are required to disinfect surfaces?’. Students may also investigate product, process or system development, such as formulating a UV-stable natural indicator.

Assessment

Outcomes	Assessment Tasks
Outcomes	(school-assessed coursework)
How do chemicals interact with water?	Tasks are selected by the teacher from the following: a report of a laboratory or fieldwork activity, including the generation of primary data comparison and evaluation of chemical concepts, methodologies and methods, and findings from at least two student practical activities reflective annotations of one or more practical activities from a logbook a summary report of selected practical investigations critique of an experimental design, chemical process or apparatus analysis and evaluation of generated primary and/or collated secondary data a modelling or simulation activity a media analysis/response problem-solving involving chemical concepts, skills and/or issues a report of an application of chemical concepts to a real-life context analysis and evaluation of a chemical innovation, research study, case study, socio-scientific issue, secondary data or a media communication, with reference to sustainability (green chemistry principles, sustainable development and/or the transition to a circular economy) an infographic a scientific poster.
How are chemicals measured and analysed?
How do quantitative scientific investigations develop our understanding of chemical reactions?	a report of a student-adapted or student-designed scientific investigation using a selected format, such as a scientific poster, an article for a scientific publication, a practical report, an oral presentation, a multimedia presentation or a visual representation

Overall Final Assessment

Overall Final Assessment

End of Semester Examination – 1.5 hours.