Chemistry 9701/23 May June 2016 | Cambridge AS Level Past Papers With Mark Scheme

1. Determination of the percentage of iron in iron wire through sulfuric acid reaction, titration with potassium dichromate(VI), calculation of moles, mass, and percentage iron using stoichiometric relationships.
2. Haber process for ammonia synthesis, including Boltzmann energy distribution, impact of higher temperatures on reaction rates, catalyst usage, temperature-pressure trade-offs, and redox reactions in nitric acid production from ammonia.
3. Fractional distillation of crude oil, structural and property trends in hydrocarbon fractions, cracking reactions of hydrocarbons, applications of products, and environmental issues including acid rain and nitrogen oxide emissions from combustion.
4. Conversion of acetoin to diacetyl using oxidation reactions, interpretation of IR spectra for functional group identification, stereoisomerism in acetoin derivatives formed with concentrated acids or HBr.
5. Bonding in iron(III) chloride influenced by electronegativity differences, hydrolysis reactions with water, and implications for ionic-covalent character in bonds.
6. Environmental impact of ammonium nitrate overuse, including eutrophication, river contamination, and nutrient imbalance, with molecular explanations tied to nitrogen cycles and aquatic ecosystems.