Chemistry 9701/42 May June 2015 | Cambridge AS Level Past Papers With Mark Scheme

1. Electronic configurations, bond energies, and thermal stabilities of hydrogen halides with comparisons of electronegativity and bond polarity effects on molecular properties.
2. Sulfur fluorides and oxides, including SF4 and SF6, their molecular geometry, dipole moments, and bonding differences compared to oxygen compounds.
3. Acid-base reactions of tin and lead oxides, relative atomic mass calculations from isotopic abundances, and thermal decomposition behavior in air.
4. Trends in solubility of Group II sulfates, precipitation reactions involving sodium sulfate and calcium sulfate, and electrolysis calculations for chromium deposition.
5. Buffer solutions involving phosphate ions, their pH control mechanisms, solubility product calculations for sparingly soluble salts, and redox equilibria involving phosphoric acids.
6. Organic reaction pathways including hydrogenation of aromatic compounds, isomerization to optically active forms, and multi-step synthesis of substituted benzene derivatives.
7. Structural and functional roles of DNA and RNA in protein synthesis, molecular-level impacts of amino acid substitution, and implications for genetic disorders like sickle cell anemia.
8. NMR and X-ray spectroscopy applications for structural analysis, including hydrogen invisibility to X-rays, group identification from chemical shifts, and spectral interpretation for compound identification.
9. Polymerization mechanisms (addition vs. condensation), environmental persistence of polyethene, biodegradable polymers like PLA, and the role of intermolecular forces in polymer melting points.