Chemistry 9701/43 Oct Nov 2014 | Cambridge AS Level Past Papers With Mark Scheme

1. Chlorine isotopes and their mass spectral peaks; abundance ratios. Strontium chloride's lattice energy calculation via Born-Haber cycle. Equations for the preparation and thermal decomposition of strontium nitrate. Thermal stability trends in Group II nitrates.

2. Ionic equation for bromate(V) and bromide reaction in acid. Determination of reaction orders, rate equation formulation, rate constant calculation with units.

3. Properties of d-block elements: degeneracy, d-orbital splitting in octahedral complexes. Reaction pathways and color changes in Cu²⁺ complexes. Mechanism and role of copper in reduction reactions. Explanation for CuCl's lack of visible light absorption. Visible light absorption and color prediction for [Cr(H₂O)₆]³⁺.

4. Comparison of conductivity in HCl and CH₃CO₂H solutions. Buffer solution definition and preparation using ethanoic acid. Buffer action illustrated by amino acid equations. Dissociation constants for tartaric acid and stereoisomeric forms.

5. Benzene bonding and shape description. Chemical reactivity of L-DOPA and vanillin with reagents, products, and structural interpretations.

6. Methoxetamine functional groups, molecular formula, chiral centers. Reaction mechanisms and product identification with LiAlH₄, HCl, and CH₃COCl.

7. Partition coefficient determination for ethoxyethane-water systems. Mass extraction calculations for sequential extractions. Role of mobile and stationary phases in chromatographic separations. Spot identification in non-polar solvent chromatograms.

8. DNA base pairing percentages from guanine content. Impact of chiral drug mixtures on dosage and potential adverse effects. Structural isomers of C₅H₁₀O and their NMR spectral predictions.

9. Polymerisation methods for nylon, PVC, and Terylene. Structural formula for Nomex polymer and protein primary structure definition. Stabilisation of α-helix secondary structure in proteins. Protein denaturation causes: alkali, Hg²⁺, and heat effects.