Chemistry 9701/21 Oct Nov 2021 | Cambridge AS Level Past Papers With Mark Scheme

1. Explanation of terms like "volatile," and analysis of the bonding and properties of carbon disulfide (CS2) compared to carbon dioxide (CO2), including bond angles and physical state differences.
2. Calculations for the enthalpy change of combustion of CS2 using given data, including definitions and thermochemical equations.
3. Analysis of hydrogen sulfide (H2S) as a weak acid and its redox reactions with oxygen, including oxidation number changes.
4. Calculation of the volume of gas produced from the decomposition of arsenic sulfide (As2S3) and the environmental consequences of releasing SO2.
5. Study of calcium reactions, including thermal stability trends, solubility properties of calcium and barium compounds, and required mass calculations for producing ammonia.
6. Description of hybridization and bonding in calcium carbide (CaC2) and the structure of calcium cyanamide (CaCN2), with relevant reaction equations.
7. Understanding phosphorus allotropes and their differing structures, oxidation states, and reaction mechanisms, including the formation of red phosphorus from white phosphorus.
8. Calculation of oxidation states and chemical equations for phosphorus reactions, and analysis of Wittig reaction mechanisms and organic synthesis pathways.
9. Reactions of phenol derivatives, including substitution and nucleophilic reactions, and identifying products in reactions with bromine.
10. Synthesis and identification of organic products in the preparation of butylamine from different starting materials, and comparison of relative basicities of amines.