Chemistry 9701/42 March 2023 | Cambridge AS Level Past Papers With Mark Scheme

1. Electron configuration of zinc(II) ion and completion of the Born–Haber diagram for ionic solid ZnS.
2. Explanation of the trend in electron affinity for Group 16 elements and comparison of lattice energies of ZnO and ZnS.
3. Entropy change prediction for the reaction of zinc oxide with carbon and the calculation of entropy for step 2.
4. Calculation of Gibbs free energy (ΔG) for the reduction of ZnS by carbon and the discussion on thermal decomposition of zinc nitrate.
5. Redox properties of hypophosphorous acid, including calculation of cell potential and the analysis of electrode reactions.
6. Chemical mechanisms, ligand exchange reactions, and equilibrium calculations for metal ion complexes, including the effect of buffer solutions on reaction rates.