§-Module

Module 6: Acid/Base Reactions

8 dot points across 3 inquiry questions, in syllabus order. Each dot point has a focused answer, with exam-style questions and worked answers where available.

Inquiry Question 1: What is an acid and a base?

Investigate the properties of acids and bases and the historical development of the Arrhenius model of acids and bases

Properties of acids and bases. Observed properties, indicator colours, the Arrhenius model, limitations of Arrhenius, and the historical development that led to Bronsted-Lowry.

9 min read →

Predict and write balanced molecular, ionic and net ionic equations for reactions of acids with active metals, metal carbonates and hydrogencarbonates, and bases (including metal oxides and hydroxides)

Acid reactions. The four reaction types, balanced molecular, full ionic and net ionic equations, the activity series, gas tests, and worked HSC past exam questions.

10 min read →

Inquiry Question 2: What happens when acids react?

Investigate the enthalpy of neutralisation, including the calorimetric determination of the heat released when strong and weak acid-base combinations react

Enthalpy of neutralisation. The standard value for strong acid plus strong base, why weak acid neutralisations release less heat, calorimetric procedure with q = mcDeltaT, and worked HSC past exam questions.

10 min read →

Inquiry Question 3: It is all about hydrogen ions

Distinguish between the strength and the concentration of acids and bases, including investigation of the degree of ionisation and the relationship between ionisation, conductivity, and pH

Strength vs concentration. The degree of ionisation, Ka and Kb values, conductivity comparison, pH at equal concentration, and worked HSC past exam questions.

9 min read →

Calculate concentration changes on dilution using c1v1 = c2v2 and predict the effect of dilution on pH for strong and weak acid and base solutions

Dilution. Concentration units (mol/L, percent w/v, ppm), the dilution equation c1v1 = c2v2, how pH changes on dilution for strong and weak acids, and worked HSC past exam questions.

10 min read →

Investigate quantitatively the relationship between the strength of conjugate acid-base pairs, including the relationship Ka times Kb equals Kw

Conjugate acid-base pair strength. The inverse relationship between conjugate strengths, the Ka times Kb equals Kw identity, salt hydrolysis predictions, and worked HSC past exam questions.

9 min read →

Investigate the application of buffer systems in natural and industrial contexts, including the bicarbonate buffer in blood and the Henderson-Hasselbalch description of buffer pH

Buffer applications. Buffer action revisited, the Henderson-Hasselbalch equation, the bicarbonate buffer in blood (HCO3/H2CO3), respiratory and renal compensation, and worked HSC past exam questions.

11 min read →

Analyse titration curves for strong-strong, strong-weak and weak-strong combinations to identify the equivalence point, distinguish it from the end point, and justify indicator selection

Titration curves. The four curve shapes, equivalence point vs end point, pH at equivalence for each combination, indicator selection rules with pKa matching, and worked HSC past exam questions.

11 min read →