Chemistry 9701/52 May June 2021 | Cambridge AS Level Past Papers With Mark Scheme

1. Enthalpy change for reaction between anhydrous and hydrated magnesium sulfate; calorimetric method; temperature measurement; enthalpy calculations.

2. Determination of acid dissociation constant (Ka) for butanoic acid using buffer solutions; pH measurement of acid-salt mixtures; relationship between pH and concentration ratio.

3. Preparation of 2.00 mol dm⁻³ solutions of sodium butanoate and butanoic acid; calculation of required volumes; systematic buffer preparation.

4. Graphical analysis of pH versus logarithmic concentration ratio; identification of anomalous points; determination of pKa from the graph.

5. Effect of temperature on pKa; inference about the enthalpy of dissociation for butanoic acid; correlation of thermodynamic and experimental data.

6. Application of calorimetry, buffer solution theory, and acid-base equilibria for evaluating thermodynamic and equilibrium properties of chemical systems.