NSW Syllabuses

# Chemistry Stage 6 - Year 12 - Module 6: Acid/Base Reactions Module 6: Acid/Base Reactions

## Outcomes

#### A student:

• CH11/12-1

develops and evaluates questions and hypotheses for scientific investigation

• CH11/12-2

designs and evaluates investigations in order to obtain primary and secondary data and information

• CH11/12-3

conducts investigations to collect valid and reliable primary and secondary data and information

• CH11/12-5

analyses and evaluates primary and secondary data and information

• CH12-13

describes, explains and quantitatively analyses acids and bases using contemporary models

## Content Focus

Students analyse how and why the definitions of both an acid and a base have changed over time, and how the current definitions characterise the many chemical reactions of acids. Acids react in particular ways to a variety of substances. These reactions follow a pattern that students identify and explore in detail.

Acids and bases, and their reactions, are used extensively in everyday life and in the human body. The chemistry of acids and bases contributes to industrial contexts and the environment. Therefore, it is essential that the degree of acidity in these situations is continually monitored. By investigating the qualitative and quantitative properties of acids and bases, students learn to appreciate the importance of factors such as pH and indicators.

## Working Scientifically

In this module, students focus on developing questions and testing hypotheses through designing, evaluating and conducting investigations to process and analyse data from acid/base reactions. Students should be provided with opportunities to engage with all the Working Scientifically skills throughout the course.

## Content

• ### Properties of Acids and Bases

• Inquiry question: What is an acid and what is a base?
• Students:
• investigate the correct IUPAC nomenclature and properties of common inorganic acids and bases (ACSCH067)
• conduct an investigation to demonstrate the preparation and use of indicators as illustrators of the characteristics and properties of acids and bases and their reversible reactions (ACSCH101)
• predict the products of acid reactions and write balanced equations to represent:
• acids and bases
• acids and carbonates
• acids and metals (ACSCH067)
• investigate applications of neutralisation reactions in everyday life and industrial processes
• conduct a practical investigation to measure the enthalpy of neutralisation (ACSCH093)
• explore the changes in definitions and models of an acid and a base over time to explain the limitations of each model, including but not limited to:
• Arrhenius’ theory
• Brønsted–Lowry theory (ACSCH064, ACSCH067)
• ### Using Brønsted–Lowry Theory

• Inquiry question: What is the role of water in solutions of acids and bases?
• Students:
• conduct a practical investigation to measure the pH of a range of acids and bases
• calculate pH, pOH, hydrogen ion concentration ($$\left[\text{H}^+\right]$$) and hydroxide ion concentration ($$\left[\text{OH}^-\right]$$) for a range of solutions (ACSCH102)
• conduct an investigation to demonstrate the use of pH to indicate the differences between the strength of acids and bases (ACSCH102)
• write ionic equations to represent the dissociation of acids and bases in water, conjugate acid/base pairs in solution and amphiprotic nature of some salts, for example:
• sodium hydrogen carbonate
• potassium dihydrogen phosphate
• construct models and/or animations to communicate the differences between strong, weak, concentrated and dilute acids and bases (ACSCH099)
• calculate the pH of the resultant solution when solutions of acids and/or bases are diluted or mixed
• ### Quantitative Analysis

• Inquiry question: How are solutions of acids and bases analysed?
• Students:
• conduct practical investigations to analyse the concentration of an unknown acid or base by titration
• investigate titration curves and conductivity graphs to analyse data to indicate characteristic reaction profiles, for example:
• strong acid/strong base
• strong acid/weak base
• weak acid/strong base (ACSCH080, ACSCH102)
• model neutralisation of strong and weak acids and bases using a variety of media
• calculate and apply the dissociation constant ($$K_a$$) and $$pK_a\,\left(pK_a=-\log_{10}\left(K_a\right)\right)$$ to determine the difference between strong and weak acids (ACSCH098)
• explore acid/base analysis techniques that are applied:
• in industries
• by Aboriginal and Torres Strait Islander Peoples
• using digital probes and instruments
• conduct a chemical analysis of a common household substance for its acidity or basicity, for example: (ACSCH080)
• soft drink
• wine
• juice
• medicine
• conduct a practical investigation to prepare a buffer and demonstrate its properties (ACSCH080)
• describe the importance of buffers in natural systems (ACSCH098, ACSCH102)