Chemistry 9701/43 Oct Nov 2021 | Cambridge AS Level Past Papers With Mark Scheme

1. Calculation of the number of hydrogen molecules, total electrons transferred, charge quantity, and current during the electrolysis of water using sulfuric acid.
2. Calculation of entropy change (∆S) and Gibbs free energy (∆G) for the reaction of water splitting, and analysis of how temperature affects reaction spontaneity.
3. Identifying the acid dissociation constant (Ka) of 4-chlorobutanoic acid and calculating pH, the ratio of acid concentrations, and the required mass of sodium propanoate for a buffer solution.
4. Explanation of the behavior of buffer solutions and the influence of sulfuric acid addition on pH.
5. Definitions and equations related to electron affinity, ionization energy, and bond energy calculations.
6. Explanation of why calcium and barium carbonates decompose at different temperatures and related mass calculations.
7. Structural analysis of complex ions such as [MnCl4]2- and [Co(H2O)6]2+, including bond angles, isomerism, and the effect of ligands.
8. Chemical equations for reactions involving copper, iodine, and sulfate, including redox processes, and the explanation of results based on electrode potentials.
9. Proton NMR analysis and identification of organic products formed in reactions of phenylamine and ethylamine with bromine.
10. Synthetic routes for phenylethanoic acid, including reagents, conditions, and mechanism explanation.